TR News - Transportation Research Board

SEPTEMBER–OCTOBER 2009NUMBER 264TR NEWSDemographic ChangesDriving ChangeEnsuring Mobility for All—Safely, Efficiently, Equitably

TRANSPORTATION RESEARCH BOARD2009 EXECUTIVE COMMITTEE*National Academy of SciencesNational Academy of EngineeringInstitute of MedicineNational Research CouncilThe Transportation Research Board is oneof six major divisions of the NationalResearch Council, which serves as anindependent adviser to the federal governmentand others on scientific andtechnical questions of national importance,and which is jointly administeredby the National Academy of Sciences, theNational Academy of Engineering, andthe Institute of Medicine. The mission ofthe Transportation Research Board is toprovide leadership in transportationinnovation and progress throughresearch and information exchange, conductedwithin a setting that is objective,interdisciplinary, and multimodal. TheBoard’s varied activities annually engageabout 7,000 engineers, scientists, andother trans portation researchers andpractitioners from the public and privatesectors and academia, all of whom contributetheir expertise in the public interest.The program is supported by statetransportation departments, federalagencies including the componentadministrations of the U.S. Departmentof Transportation, and other organizationsand individuals interested in thedevelopment of transportation.The National Research Council was organizedby the National Academy ofSciences in 1916 to associate the broadcommunity of science and technologywith the Academy’s purposes of furtheringknowledge and advising thefederal government. Functioning inaccordance with general policies determinedby the Academy, the Council hasbecome the principal operating agencyof both the National Academy ofSciences and the National Academy ofEngineering in providing services to thegovernment, the public, and the scientificand engineering communities.www.TRB.orgChair: Adib K. Kanafani, Cahill Professor of Civil Engineering, University of California, BerkeleyVice Chair: Michael R. Morris, Director of Transportation, North Central Texas Council of Governments,ArlingtonExecutive Director: Robert E. Skinner, Jr., Transportation Research BoardJ. Barry Barker, Executive Director, Transit Authority of River City, Louisville, KentuckyAllen D. Biehler, Secretary, Pennsylvania Department of Transportation, HarrisburgLarry L. Brown, Sr., Executive Director, Mississippi Department of Transportation, JacksonDeborah H. Butler, Executive Vice President, Planning, and CIO, Norfolk Southern Corporation, Norfolk,VirginiaWilliam A. V. Clark, Professor, Department of Geography, University of California, Los AngelesDavid S. Ekern, Commissioner, Virginia Department of Transportation, RichmondNicholas J. Garber, Henry L. Kinnier Professor, Department of Civil Engineering, University of Virginia,CharlottesvilleJeffrey W. Hamiel, Executive Director, Metropolitan Airports Commission, Minneapolis, MinnesotaEdward A. (Ned) Helme, President, Center for Clean Air Policy, Washington, D.C.Randell H. Iwasaki, Director, California Department of Transportation, SacramentoSusan Martinovich, Director, Nevada Department of Transportation, Carson CityDebra L. Miller, Secretary, Kansas Department of Transportation, Topeka (Past Chair, 2008)Neil J. Pedersen, Administrator, Maryland State Highway Administration, BaltimorePete K. Rahn, Director, Missouri Department of Transportation, Jefferson CitySandra Rosenbloom, Professor of Planning, University of Arizona, TucsonTracy L. Rosser, Vice President, Regional General Manager, Wal-Mart Stores, Inc., Mandeville, LouisianaRosa Clausell Rountree, CEO–General Manager, Transroute International Canada Services, Inc., PittMeadows, British ColumbiaSteven T. Scalzo, Chief Operating Officer, Marine Resources Group, Seattle, WashingtonHenry G. (Gerry) Schwartz, Jr., Chairman (retired), Jacobs/Sverdrup Civil, Inc., St. Louis, MissouriC. Michael Walton, Ernest H. Cockrell Centennial Chair in Engineering, University of Texas, Austin (PastChair, 1991)Linda S. Watson, CEO, LYNX–Central Florida Regional Transportation Authority, Orlando (Past Chair, 2007)Steve Williams, Chairman and CEO, Maverick Transportation, Inc., Little Rock, ArkansasThad Allen (Adm., U.S. Coast Guard), Commandant, U.S. Coast Guard, Washington, D.C. (ex officio)Peter H. Appel, Administrator, Research and Innovative Technology Administration, U.S. Department ofTransportation (ex officio)J. Randolph Babbitt, Administrator, Federal Aviation Administration, U.S. Department of Transportation (exofficio)Rebecca M. Brewster, President and COO, American Transportation Research Institute, Smyrna, Georgia (exofficio)George Bugliarello, President Emeritus and University Professor, Polytechnic Institute of New York University,Brooklyn; Foreign Secretary, National Academy of Engineering, Washington, D.C. (ex officio)James E. Caponiti, Acting Deputy Administrator, Maritime Administration, U.S. Department of Transportation(ex officio)Cynthia Douglass, Acting Deputy Administrator, Pipeline and Hazardous Materials Safety Administration,U.S. Department of Transportation, Washington, D.C. (ex officio)LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior,Washington, D.C. (ex officio)Edward R. Hamberger, President and CEO, Association of American Railroads, Washington, D.C. (ex officio)John C. Horsley, Executive Director, American Association of State Highway and Transportation Officials,Washington, D.C. (ex officio)Rose A. McMurray, Acting Deputy Administrator, Federal Motor Carrier Safety Administration, U.S.Department of Transportation (ex officio)Ronald Medford, Acting Deputy Administrator, National Highway Traffic Safety Administration, U.S.Department of Transportation (ex officio)Victor M. Mendez, Administrator, Federal Highway Administration, U.S. Department of Transportation(ex officio)William W. Millar, President, American Public Transportation Association, Washington, D.C. (ex officio)(Past Chair, 1992)Peter M. Rogoff, Administrator, Federal Transit Administration, U.S. Department of Transportation (ex officio)Joseph C. Szabo, Administrator, Federal Railroad Administration, U.S. Department of Transportation (exofficio)Polly Trottenberg, Assistant Secretary for Transportation Policy, U.S. Department of Transportation (ex officio)Robert L. Van Antwerp (Lt. General, U.S. Army), Chief of Engineers and Commanding General, U.S. ArmyCorps of Engineers, Washington, D.C. (ex officio)* Membership as of October 2009.

TR NEWSNUMBER 264 SEPTEMBER–OCTOBER 2009DEMOGRAPHIC CHANGES DRIVING CHANGE43 INTRODUCTIONChanging Demographics Change the Transportation SystemJoseph F. Coughlin, Robin Kline, and Katherine F. TurnbullAge, income, gender, ethnicity, household size, and automobile availability are some of thevariables that influence travel behavior and transportation demand for different modes.Articles in this issue highlight information presented at a 2008 conference on the Impact ofChanging Demographics on the Transportation System.4 Travel Demand in the Context of Growing Diversity:Considerations for Policy, Planning, and ForecastingHeather Contrino and Nancy McGuckinAs U.S. society increases in diversity in the next few decades, a significant portion of growthin travel demand will come from minority populations. The authors explore differences intravel behavior that can have wide-reaching consequences for short- and long-term policydevelopment, planning, and travel demand forecasting.9 Preparing the Transportation System for Demographic Changes:Conference Explores Research NeedsKatherine F. Turnbull10 Changes in Travel Characteristics by Gender:U.S. Commuting Trends from a National Sample, 1985–2005Randall CraneWomen’s travel is changing more than men’s, with the increased participation of women inthe workforce. Data from the American Housing Survey indicate, for example, that thegender gap for commute trip length is converging, although slowly. The author exploresrelated trends and their implications for transportation policy and planning and identifiestopics for further research.13 Focusing on Demographic Changes and the Transportation System:TRB Activities Under WayKatherine F. Turnbull101914 Key Issues in Transportation and Aging:Ensuring Safe Mobility for Older AdultsDavid W. EbyBaby boomers are expected to bring a culture of “automobility” into older adulthood, holdingonto licenses longer and driving more than previous generations. The author reviewsapproaches to help those who are able to drive safely continue to do so, through drivingevaluation, education and rehabilitation, vehicle design and modification, advancedtechnology, and roadway design.19 The Safety and Mobility Patterns of Older Women in 2030:Defining and Meeting the ChallengesSandra Rosenbloom and Susan HerbelOlder women today must make a complicated choice—to continue to drive and face anincreased risk of serious injury or death or to restrict or cease driving and face the greater riskof social and emotional isolation. Examining differences in the travel behavior of olderwomen and men, the authors explore mobility and safety options to allow older people,particularly women, to maintain their independence and access in safety.COVER: Demographic changesbring changes in travel needs andpreferences—researchers arestudying the trends to prepare foradjustments to transportationsystems and services. (Photo: JohnA. Rizzo, Getty Images)

INTRODUCTIONJOSEPH F. COUGHLIN, ROBIN KLINE, AND KATHERINE F. TURNBULLThe face of the UnitedStates of America isundergoing change. Thepopulation is more ethnicallydiverse, is getting older, andis increasing in numbers.These trends are forecast tocontinue. The U.S. CensusBureau projects that thenation’s population will growto 438 million by 2050, anearly 43 percent increasefrom today’s population ofapprox imately 307 million.The Census Bureau estimatesthat 80 percent of thisincrease will come fromimmigrants and their descendants.At the same time, moreAmericans are living inmegaregions; telecommutingand alternative workarrangements are gaining adoption; and one-person householdsare increasing. With dynamic changes in national andglobal economic activity, uncertainty about the availabilityand cost of energy, and rapid advances in technology, a differentpicture emerges of the United States in 2050.All of these factors have significant implications for thetransportation system. The sociodemographic and economiccharacteristics of the population influence transportationdemand for different modes. Age, income,gender, ethnicity, household size, and automobile availabilityare some of the variables that influence travel behavior.Providing safe mobility for the aging baby boomgeneration, for a more ethnically diverse population, andfor a larger population is critical for the nation’s economicvitality and quality of life.The Transportation Research Board (TRB) is at the forefrontof examining the potential impacts of demographicchanges on the transportation system. TRB technicalstanding committees are sponsoring specialty conferences,workshops, and Annual Meeting sessions on a range ofrelated topics. Committees also are developing researchproblem statements and areassisting in the disseminationof results from current studies.TRB’s National CooperativeHighway ResearchProgram is launching a majorresearch project on the effectsof sociodemographics ontravel behavior.This issue of TR News highlightsinformation presentedat the 2008 conference on theImpact of Changing Demographicson the TransportationSystem, sponsored by theResearch and Innovative TechnologyAdministration of theU.S. Department of Transportation,and organized byTRB. Articles on the changingracial and ethnic mix andtransportation, gender differencesand transportation,aging and transportation, and the mobility and safety ofolder women highlight current research. TRB continues topursue activities to improve understanding—and to predictthe influence—of sociodemographic changes on thetransportation system.The authors served on the Planning Team for the 2008Impact of Changing Demographics on the TransportationSystem Conference, chaired by Coughlin, who is Director ofthe New England University Transportation Center and Age-Lab at the Massachusetts Institute of Technology, Cambridge.Kline is a University Program Specialist with theResearch and Innovative Technology Administration, Washington,D.C. Executive Associate Director of the Texas TransportationInstitute, College Station, Turnbull chairs the TRBPlanning and Environment Group.EDITOR’S NOTE: Appreciation is expressed to TRB Senior ProgramOfficer Thomas R. Menzies, Jr., for his contributionsin developing this issue of TR News.TR NEWS 264 SEPTEMBER–OCTOBER 20093

Driving ChangeTravel Demand in theContext of Growing DiversityConsiderations for Policy, Planning, and ForecastingHEATHER CONTRINO AND NANCY McGUCKINContrino is TravelSurveys ProgramManager, Office ofHighway PolicyInformation, FederalHighway Administration,Washington, D.C.McGuckin is a TravelBehavior Analyst in SouthPasadena, California.The United States is experiencing a periodof change—the economy is struggling,fuel prices are erratic, environmentalissues are prominent, roadway capacityhas reached a peak in large urban areas, and demographicsare undergoing major shifts. In the past fivedecades, changes in travel volumes and behavior havecoincided with dramatic changes in the economy, culture,development patterns, and technology (1).The growth in travel since the 1960s is a productof demographic and economic changes, includingincreases in vehicle ownership, the entrance of babyboomers—especially women—into the workforce,and growth in personal income (2). Recent data fromthe Highway Performance Monitoring System, TrafficVolume Trends, and preliminary results from the 2008National Household Travel Survey, however, indicatethat demand is slowing and occasionally declining.Whether or not this is a continuing trend has yetto be determined, but the economic slowdown, anUnderstanding the interaction of household size,automobile availability, and travel demand, and thedifferences and needs across specific populationgroups, is critical in assessing trends, the viability ofprograms, and the impacts of projects and policy.aging population, an influx of new immigrantgroups, the saturation of vehicle ownership, concernsabout the environment, and unpredictable fuelTR NEWS 264 SEPTEMBER–OCTOBER 20094A naturalizationceremony at MountVernon, Virginia.According to the 2005 U.S.Census, immigrants makeup about 12.1 percent ofthe country’spopulation—the highestproportion in nearly 100years. New immigrants’travel patterns differ atfirst from those of theU.S.-born population.PHOTO: U.S. CITIZENSHIP AND IMMIGRATION SERVICES

costs could have an impact on travel demand in theUnited States. Some of these phenomena may exertmore influence than others, but the growing diversityof the U.S. population and changes in the socialnorms of travel play important roles in shaping traveldemand.Highway finance, congestion, land use planning,air quality, fuel costs, oil dependency, global warming,the virtual marketplace, and infrastructureinvestment are some of the issues challenging theperformance and use of the U.S. transportation system(3). Understanding the people who travel—especially the differences in travel demand and theneeds across specific population groups—is criticalin assessing current and future trends, the viability ofprograms, and the impacts of projects and policy onsystem users.Household Travel in ContextHousehold travel generates more than 80 percent ofthe total vehicle miles of travel in the United States;freight and commercial vehicles produce the remainder.Historically, when the rate of growth in travelexceeds the rate of population growth, several influencesare at work, including the age distribution ofthe population, the levels of automobile ownership,licensure rates, household size, participation in thelabor force, and real personal income per capita (4).African-American, Hispanic, and—to someextent—Asian households vary from white householdsin terms of these key factors. Minority groupscommonly have less ownership of automobiles,lower household income, greater household size,lower levels of participation in the labor force, lowerrates of licensure, and a concentration of populationin urban areas.Population Growth and AgeDistributionThe white population in the United States is projectedto remain relatively stable over the next 40years; the current minority groups will be the maincontributors to population growth. The number ofHispanics is expected to grow by 188 percent; theAsian population to grow by 213 percent, and theblack population—Hispanic and non-Hispanic—isexpected to grow to 61.4 million in size (4).Significantly larger percentages of African-Americans,29.2 percent, and of Hispanics, 31.9 percent,are under the age of 16, compared with 20.6 percentof whites and 21.6 percent of Asians. Minority populationstherefore will have an increasing influenceon travel needs, preferences, volumes, and behaviorin the future as they enter the workforce and startfamilies (3).Household travel—such as supermarket trips (above) and picking up children fromschool (below)—generates more than 80 percent of the total vehicle miles of travelin the United States.Vehicle Availability andLicensure RatesPeople in poorer households without a reliable vehicle,or with no vehicle at all, have a greatly reducedlevel of mobility. When they have vehicles, the vehiclesare more likely to be older models, which oftenrequire more maintenance; moreover, the lower vehicleefficiency increases the cost of travel for thehousehold.A high percentage of African-American, Hispanic,and Asian households have no vehicle (Table 1). InTABLE 1 Zero-Vehicle Households (5)White 7.3%African-American 23.8%Hispanic 17.2%Asian 12.7%All 10.3%PHOTO: DAN BURDENPHOTO: DAVID PARISI, PARISI ASSOCIATES TRANSPORTATION CONSULTINGTR NEWS 264 SEPTEMBER–OCTOBER 20095

Teens take a driver’seducation class. Driverlicensure rates amongAfrican-American andAsian women are lowcompared with the ratesfor their malecounterparts; licensureoften is affected bycultural and economicfactors.PHOTO: AAA FOUNDATION FOR TRAFFIC SAFETYTR NEWS 264 SEPTEMBER–OCTOBER 20096the United States, 10.3 percent of all households haveno vehicle; for African-American households, however,the rate is 23.8 percent and for Hispanic households,17.2 percent. The availability of safe,alternative modes of travel will gain importance intransportation planning as these populations grow.Licensure rates reveal age and gender differences.As shown in Table 2 (below), African-American andAsian women have very low rates of licensure comparedwith the rates for their male counterparts.Income constraints and cultural norms often influencelicensing, especially for immigrant women, andmust be considered when predicting the travel needsof minority populations (5).TABLE 2 Gender, Race, and Licensure Rates (5)White Black Asian OtherMale 91.8% 77.9% 87.2% 82.3%Female 88.8% 72.0% 76.6% 70.3%Total 90.2% 74.4% 81.9% 76.2%TABLE 3 Annual Trip Rates, Vehicle Ownership, and Vehicle OccupancyHousehold Size and Travel RatesThe interaction of household size, automobile availability,and travel demand is fundamental. For example,Table 3 (below) shows that Hispanic householdsproduce the greatest amount of travel annually—5,000 trips per household per year—but the numberof trips per person is among the lowest. This is aresult primarily of higher-than-average householdsize.Hispanic households also have the highest vehicleoccupancy at 1.8 persons per vehicle trip. A largeinflux of new immigrants, combined with lower levelsof vehicle ownership, concentration in urban centers,larger households, and lower incomes,contributes to the car sharing that is common amongHispanic households—a unique characteristic oftheir travel behavior.Mode UseBlacks, Asians, and Hispanics are more frequentusers of alternative modes of transportation than arewhites (6). For example, Asians travel 6.5 times moreTrips per Trips per Vehicles per VehicleHousehold Person Household OccupancyWhite Non-Hispanic 3,693.9 1,525.2 1.99 1.51Black Non-Hispanic 3,609.5 1,318.9 1.38 1.55Asian Non-Hispanic 3,868.6 1,342.5 1.74 1.58Hispanic 4,979.5 1,327.9 1.69 1.80Source: 2001 National Household Travel Survey, FHWA Office of Highway Policy Information

PHOTO: DAN BURDENMiles per Annum1600140012001000800600400200Per person, Hispanics walk 75 percent more miles onaverage than all other ethnic groups.0WhiteAfrican-AmericanAsianPublic TransitWalkSource: 2001 National Household Travel Survey, FHWA Office of Highway Policy InformationHispanicWhiteAfrican-AmericanAsianHispanicmiles on transit per person per year than whites do.Hispanics walk 75 percent more miles on average perperson than all other groups. The differences in transitand walk miles per person per year are shown inFigure 1 (above right).Time spent commuting is often considered anindicator of quality of life, because more time spentin travel takes away from other home activities. Commutingtime is a function of distance, congestion onthe route, and mode of transportation. Of all races andethnic groups, whites are the least likely to spendmore than 1 hour commuting to work; only 10.6 percentof blacks, 10.3 percent of Asians, and 9.1 percentof Hispanics have commuting times of 1 hour or less(Table 4, below).TABLE 4 Commuting Time, All Modes (5)60 minutesWhites 48.3% 7.1%African-Americans 39.0% 10.6%Asians 38.6% 10.3%Hispanics 44.0% 9.1%Race, Ethnicity, and ImmigrationIn the United States, discussions of race and ethnicityoften involve immigration. Although the recenteconomic downturn has slowed the pace of immigration,the U.S. Census showed in 2005 that an estimated12.1 percent of the U.S. population wereimmigrants—the highest percentage since 1920 (Figure2, page 8). This historic influx of new races, ethnicities,and cultures will have an impact on thedemographic makeup of the U.S. population and onthe distribution and characteristics of travel demand.Policy and program plans therefore should incorporatean understanding of the different travel experiences,options, and needs of new immigrants. Atfirst, immigrants travel differently from the populationborn in the United States, relying to a greaterextent on transit, walking, and carpooling. As immigrantsassimilate into society, their travel patternsassimilate and become more dependent on personalvehicles (7–11). Asian immigrants make a faster transitionto automobile use than other immigrantgroups. Even after 20 years as residents, however,Hispanic immigrants remain more likely to use transitthan the population born in the United States; thismay result from many factors, including lower automobileavailability (Figure 3, page 8).PHOTO: TIM ADAMS, TRANSITPEOPLEFIGURE 1 Annual milestraveled via transit andon foot.Two girls ride a LosAngeles bus. Blacks,Asians, and Hispanics aremore frequent users ofalternative modes oftransportation than arewhites.TR NEWS 264 SEPTEMBER–OCTOBER 20097

TR NEWS 264 SEPTEMBER–OCTOBER 2009MillionsPercent4035302520151001900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2005YearFIGURE 3 Immigranthouseholds with zerovehicles, by years of U.S.residency.25201510503 yearsor less4-6years7-8years9-10yearsYears of Residency Hispanic> 10yearsresident15.0%13.0%11.0%9.0%7.0%5.0%3.0%1.0%-1.0%Source: Decennial Census for 1990 to 2000, Center for Immigration Studies and Analysis of March2005 Current Population Survey DataFIGURE 2 Immigrants inthe United States,1900–2005. AllU.S.bornPercent of PopulationProspects for the FutureThe United States historically has been characterizedas a melting pot, and if trends continue, currentracial and ethnic minorities will fuel much of thefuture growth in travel demand. On average, minoritiesare more dependent on transit, have higher occupancylevels in automobiles, and have lower levels ofvehicle ownership. Initiatives that focus on tolling,infrastructure development, land use planning, andhighway finance can benefit from information aboutthe travel behavior, options, and needs of minoritygroups.Understanding the differences in travel behaviorand the possible explanations for these differencescan help in modeling travel demand, in finding thepolicies best suited for the travel needs of all populationgroups, and in addressing concerns aboutenvironmental justice (12). As U.S. society increasesin diversity in the next few decades, a significantportion of growth in travel demand will come fromminority populations. The differences in travelbehavior have wide-reaching consequences for shortandlong-term policy development, planning, andtravel demand forecasting.References1. Polzin, S., and X. Chu. Exploring Long-Range U.S. TravelDemand: A Model for Forecasting State-Level Person Milesand Vehicle Miles of Travel for 2035 and 2055. Prepared forthe Office of Policy, Federal Highway Administration,Washington, D.C., 2007.2. Polzin, S., X. Chu, and L. Toole-Holt. Forecasts of FutureVehicle Miles of Travel in the United States. In TransportationResearch Record: Journal of the TransportationResearch Board, No. 1895, Transportation Research Boardof the National Academies, Washington, D.C., 2004, pp.147–155.3. Polzin, S. The Case for Moderate Growth in Vehicle Miles ofTravel: A Critical Juncture in U.S. Travel Behavior Trends.U.S. Department of Transportation, Washington, D.C.,2006.4. Sun, S. Analysis of Changing Relationships Among PopulationGrowth, Passenger Travel Growth, and Vehicle Miles ofTravel Growth for Different Modes. Prepared for theNational Surface Transportation Policy and Revenue StudyCommission, Washington, D.C., 2007.5. Pisarski, A. NCHRP Report 550–TCRP Report 510: Commutingin America III: The Third National Report on CommutingPatterns and Trends. Transportation Research Boardof the National Academies, Washington, D.C., 2006.6. Duthie, J., K. Cervenka, and S. T. Waller. EnvironmentalJustice Analysis: Challenges for Metropolitan TransportationPlanning. In Transportation Research Record: Journalof the Transportation Research Board, No. 2013, TransportationResearch Board of the National Academies,Washington, D.C., 2007, pp. 8–12.7. Contrino, H. Implication of Alternative Assumptions ConcerningFuture Immigration on Travel Demand for DifferentModes. Prepared for the National Surface TransportationPolicy and Revenue Study Commission, Washington,D.C., 2007.8. PSC Research Report No. 02-5208. Population StudiesCenter, University of Michigan, Ann Arbor.9. McGuckin, N. Mobility and the Melting Pot. NHTS Brief,National Household Travel Survey, Federal HighwayAdministration, Washington, D.C., January 2006.10. Contrino, H., and N. McGuckin. Travel Characteristics ofNew Immigrants. NHTS Brief, National Household TravelSurvey, Federal Highway Administration, Washington,D.C., August 2006.11. Blumenberg, E., and K. Shiki. Transportation Assimilation:Immigrants, Race, and Ethnicity, and Mode Choice. Presentedat 85th Annual Meeting of the TransportationResearch Board, Washington, D.C., 2006.12. Tal, G., and S. Handy. The Travel Behavior of Immigrantsand Race/Ethnicity Groups: An Analysis of the 2001 NationalHousehold Travel Survey. Institute of Transportation Studies,University of California, Davis, 2005.8Source: U.S. Census, Public Use Microdata Sample

Preparing the Transportation System for Demographic ChangesApproximately 110 researchers,practitioners, and policy makersgathered in Washington, D.C.,in October 2008 to discuss theimplications that a range of demographicchanges may have for theU.S. transportation system. Supportedby the U.S. Department ofTransportation’s Research andInnovative Technology Administration(RITA), organized by theTransportation Research Board(TRB), and oriented to universitytransportation centers, the Impactof Changing Demographics on theTransportation System Conferencefocused on the impact of fourdemographic forces on transportationover the next 20 years:u Aging and demographic transition,u Immigration internally and from abroad,u Changing racial and ethnic mix, andu Gender differences.Conference Explores Research NeedsKATHERINE F. TURNBULLHeather Contrino, FHWA, speaks at a plenary session of theImpact of Changing Demographics on the TransportationSystem Conference, October 2008, at the Keck Center of theNational Academies, Washington, D.C.; her subject was“Demographics Matters: Travel Demand, Options, andCharacteristics Among Minority Populations.”The program featured keynote speakers, breakoutsessions, and an interactive poster session on the effectsof the four demographic forces on transportation systemdemand and on safe mobility. Speakers highlightednational trends and recent studies from urban and ruralareas throughout the country.During the discussion sessions, participants identifiedknowledge gaps and issues for research. One criticalknowledge gap is the scarcity of data on key demographicand transportation characteristics. Developingand maintaining these data at the national and local levelsemerged as a priority for researchers, public agencies,and policy makers.The breakout groups extensively discussed the effectsof the aging of the baby boom generation on the transportationsystem. The actions and activities of this agegroup will have significant impacts on housing and landuse patterns, use of travel modes, and safety. Manyresearch ideas were identified to track the travel behaviorof baby boomers and the changes that develop in theirbehavior over time and to obtain information on boomers’preferences for housing, social services, and cultural andrecreational amenities that can influence travel patterns.Participants identified a variety of research needs toimprove understanding of the relationship among familycharacteristics, age, social networks, and travel behaviorin different population groups. The impacts ofone-person households, nonwork travel, informal transportationservices, and the driver safety risks associatedwith different groups were cited as other topics for furtherresearch.Many participants favored a multidisciplinaryapproach in the research to address these and otherquestions. Several emphasized the need to provideelected and appointed officials with information to assistin decision making for public policy.The conference proceedings will be released as aTransportation Research Circular on the TRB website;many presentations are posted online at http://onlinepubs.trb.org/onlinepubs/archive/conferences/2008/ImpactDemographics/pdf/Program.pdf.The author is Executive Associate Director, TexasTransportation Institute, Texas A&M University, CollegeStation, and Chair of the TRB Planning andEnvironment Group.TR NEWS 264 SEPTEMBER–OCTOBER 20099

Driving ChangeChanges in Travel Characteristicsby GenderU.S. Commuting Trends from a National Sample, 1985–2005RANDALL CRANEThe author is Professorand Vice Chair, UrbanPlanning, and AssociateDirector, Institute ofTransportation Studies,University of California,Los Angeles.Researchers are fundamentally interestedin how demographic characteristics areassociated with different kinds of travel,travel modes, and travel outcomes. Docertain demographic characteristics generate moretravel, or do they restrict travel—and what is themagnitude of these changes? Which demographiccharacteristics have the most and the least influenceon transportation demand, and which are changingthe most and the least?Gender and the CommuteOne topic for focus is the association between genderand the commute. The commute anchors manyother travel purposes and is the basic tie between thelabor and the housing markets. Female behaviors inboth markets are changing more than those ofmales—taking stock of these trends for the purposesof transportation policy therefore is timely.For several years, women’s rates of participationin the workforce have gained on those of men. Theliterature nevertheless continues to document a gendergap in commuting distances and times, with menhistorically commuting farther and longer. The mostpopular explanation is that women traditionally havea greater share of home- and child-centered responsibilities.A second explanation notes the concentrationof women in part-time and lower-wage jobs,which intuitively do not justify long commutes.Both these in-home and out-of-home labor explanationsare subject to change in changing times—although how the trends vary by place and byPHOTO: DAN BURDENTR NEWS 264 SEPTEMBER–OCTOBER 200910Women’s travel ischanging more thanmen’s.

personal characteristics also matters. Yet women’sincreased participation in the workforce and theirincreased orientation to careers in their educationand their work plans—a so-called “quiet revolution”—mightbe expected to reduce the gender gapfor commutes. Recent data for San Francisco, California,and for Quebec City in Canada indicate thatthe gap is closing for some groups of men andwomen.Data from a national survey that covers the pasttwo decades also can be applied. Every 2 years, theCensus Bureau conducts the American Housing Survey(AHS) for the U.S. Department of Housing andUrban Development. Residents of many of the same50,000 housing structures, considered nationallyrepresentative, have been sampled for each surveysince 1985, and details have been gathered on theindividuals. This has produced cross-sectional databy year and a longitudinal panel over time. The AHSasks basic questions about the commute trip, includingthe mode used, the distance traveled, and thetravel time. Some interesting trends emerge from theAHS commute data for 1985 to 2005.Distances and Travel TimeThe AHS data indicate that all commutes are lengtheningon average, with travel distances increasing 1percent per year, and travel times increasing at abouthalf that rate. From 1985 to 2005, the commute distancefor women increased by 30 percent, to 11.8miles; and the commute distance for men increasedby 22 percent, to 14.1 miles (Figure 1, below). Thissuggests that the gender gap for commute trip lengthis converging, although slowly.The average travel time for a commute, however,increased slightly more for men than for women overthe two decades recorded by the survey. The averagetravel time for women’s commutes increased approximately9 percent, to 21.1 minutes; the average traveltime for men’s commutes increased approximately 10percent, to 23.5 minutes.Gender and RaceDifferences between travelers cannot be reduced togender only—the interactions of other demographicfactors should be examined also and can prove criticalover time. An examination of the growth in distancecommuted in personal vehicles, by gender andrace, reveals that the commute distance of whitemales changed little over the two decades, but commutedistance for Hispanic women, black females,and Hispanic males increased. The details of thesepatterns remain understudied, and the factors thatinfluence the patterns need more research.The AHS data on mode use for one-way commutetravel indicate that men and women havehigher average travel times on public transit. Thetravel times by transit for men and women, however,are similar, suggesting less of a gender gap amongtransit riders than among commuters using personalvehicles.Examining mode split by gender and race indicatesthat white males and females have low levels oftransit use on commute trips. Blacks have the highestuse of transit, yet from 1985 to 2005, use by blackwomen declined dramatically, by approximately 50percent. Transit use by black males also declined,Women and a childwaiting at a Portland,Oregon, bus stop. Traveltimes on public transitare similar for men andwomen.From 1985 to 2005, theuse of transit by blackwomen declined byapproximately 50percent.PHOTO: LAURA SANDT15131011.69.1WomenMen12.810.91985 1995 200514.111.8FIGURE 1 Commute distances for women and men,1985–2005 (in miles).TR NEWS 264 SEPTEMBER–OCTOBER 200911

The gap in men’s andwomen’s commutedistances decreases forsingle-adult householdswith children but remainslarge for married-couplehouseholds with childrenand both parentsworking.In 1985, the smallest difference in male andfemale commute distances by family status was forheads of single-adult households with children; thelargest gap was for married-couple households withchildren and both parents working. This trend isconsistent with the economics of gender and ofhouseholds.The data also indicate that the gender gapincreased for single-adult households with no childrenand for married-couple households with nochildren, but decreased in single-adult householdswith children and married-couple households withchildren. Working women in households with childrenare commuting farther than they had in thepast, especially in comparison with the distancestraveled by their spouses.Marriage is associated with shorter commutesfor women, but children are not an influencing factorstatistically. Perhaps the presence of childrenincreases the income needs of the household, whichmay result in women working farther away, evenwhile their home-centered responsibilities remain.Better data and more study would clarify these relationships.TR NEWS 264 SEPTEMBER–OCTOBER 2009but not as sharply. More research is needed to examinethese trends, especially the decline in the use oftransit by black women.Age and Family TypeYounger age groups have the smallest gender gap(Figure 2, below). The largest differences occuramong men and women in the age group of 35 to 54years old. Although the commute distance forwomen in that group declines, the decline was lessin 2005 than it was in 1985.0%–13%–25%–38%–50%16-251985 200526-3435-4445-5455-6465+FIGURE 2 Women’s commute distances as percent ofmen’s, by age (via private vehicles).Substantial DifferencesGender has an influence on commuting patterns,but how this influence is changing with women’schanging participation in the workforce is complicated.Although men continue to commute fartherand somewhat longer, women are catching up. Inparticular, the commutes of married women withchildren are lengthening at a rate three times fasterthan that for the commutes of their working husbands.The gender gap is smallest for youngerwomen, and this characteristic is carrying throughas the cohort ages. The gap is most pronouncedamong whites, though the once-wide gap in modeavailability and choice among white and minoritywomen is quickly narrowing.If women are traveling more like men, does thisargue for a decreased focus on gender in transportationplanning? No, because the differencesare still substantial, especially when viewed in thecontext of other demographic factors. Men andwomen travel differently, and the variation inbehaviors and circumstances linked to genderrequires more detailed exploration.The AHS data may be hinting that the continuedrise of dual-earner families of more comparableearning levels is leading to longer commute tripsand to less reliance on transit. More detailed resultson these issues will be reported soon.12

Focusing on Demographic Changes andthe Transportation SystemIn addition to organizing the 2008 conference on theImpact of Changing Demographics on the TransportationSystem, the Transportation Research Board(TRB) has undertaken many other activities to improveunderstanding and to anticipate the influence ofsociodemographic changes on the transportation system.These activities include other specialty conferences,sessions at the TRB Annual Meeting, committee efforts,and a National Cooperative Highway Research Program(NCHRP) project.TRB Activities Under WayKATHERINE F. TURNBULLu Other specialty conferences. The TRB Women’sIssues in Transportation Committee has sponsored fourinternational conferences. The 2009 InternationalConference on Women’s Issues in Transportationaddressed a range of topics on women’s travel needs andtravel patterns—from driving to “fampooling” to bicyclingto walking to riding the bus and even to racecardriving. Cosponsored by several federal, state, university,and international organizations, these conferences havebecome a focal point for the discussion of women’sissues in transportation in the United States and othernations and for the advancement of needed research.u Annual Meeting sessions. Sessions at TRB AnnualMeetings have elevated the importance of identifyingthe impacts of sociodemographic changes on the transportationsystem. A session at the 2009 Annual Meetinghighlighted presentations by key speakers at the Impactof Changing Demographics on the TransportationSystem Conference. The National Transportation DataRequirements and Programs Committee is sponsoring aworkshop at the 2010 Annual Meeting on the results ofthe 2008 National Household Travel Survey and a sessionon the links among walking and bicycling, socioeconomicsand demographics, and mobility and livability.u Committee activities. TRB Technical Activities committees,sections, and groups are pursuing a variety ofactivities to advance the understanding of the impact ofsociodemographic changes on travel behavior and thetransportation system. The topic is one of the crosscuttingissues taken up by the Policy and OrganizationGroup. Data Section committees have several effortsunder way to maximize use of the 2010 Census andrelated surveys. The Transportation Education andTraining Committee has sponsored Annual Meetingworkshops on the impact of sociodemographic changeson the transportation workforce.u NCHRP project. NCHRP Project 20-83(06), Effects ofSociodemographics on Travel Demand, is starting up inspring 2010 to assess the possible effects of sociodemographicfactors on travel demand over the next 50 years.The second objective is to identify strategies and actionsto assist state departments of transportation and otheragencies to plan and prepare for plausible future scenarios.The research will enhance understanding of therelationship between social, demographic, and economicfactors and travel demand.More information on these activities is available atwww.TRB.org.TR NEWS 264 SEPTEMBER–OCTOBER 200913

Driving ChangeKey Issues in Transportation and AgingEnsuring Safe Mobility for Older AdultsDAVID W. EBYThe author is ResearchScientist and Head,Social and BehavioralAnalysis Division,University of MichiganTransportation ResearchInstitute, and Director,Michigan Center forAdvancing SafeTransportationThroughout the Lifespan,Ann Arbor.During the past decade, research and educationalefforts have focused on maintainingsafe mobility for older adults—arecent book on the topic cites nearly 900references (1). The attention is appropriate, yet theproblems are far from solved. The populations ofmost Western nations are aging with the aging ofthe baby boomers, who are expected to bring a cultureof “automobility” into older adulthood, holdingonto licenses longer and driving more than previouscohorts.Age-related medical conditions and the medicationsto treat these conditions, however, can make safe drivingdifficult for some older adults. Several recent studieshave confirmed that as a group, adults 70 years oldand older are at a higher risk for a fatal crash, and thatcrashes involving this age group tend to occur at timesand places typically considered safe (2).Driving cessation, however, has been linked tomany negative outcomes, and nondriving mobilityoptions are limited in most areas. Society therefore isfacing a serious community mobility problem.The many issues of aging and mobility have threecomplementary and interdependent goals (1):u To understand and manage the effects of medicalconditions and medications on the skills neededfor safe driving;u To help those who are able to drive safely continueto do so; andu To identify and provide community mobilitysupport to those who are no longer able to drive.Medical Conditions andDriving SkillsConcerted research efforts have examined the relationshipbetween older driver crash risk, specificmedical conditions, and the medications used to treatthem. Excluding vision-related problems, theresearch has not found strong links between medicalTR NEWS 264 SEPTEMBER–OCTOBER 200914The aging baby boomgeneration is expected tocontinue driving longerand driving more thanolder adults in previousgenerations.PHOTO: AAA FOUNDATION FOR TRAFFIC SAFETY

conditions and older adult crash risk (1, 3, 4).Several researchers have pointed out the difficultiesof linking crash risk with medical conditions,noting that crash risk is influenced by many factors.Not all medical conditions influence crash risk to thesame degree, and individuals with the same conditiondiffer greatly in how they are affected (3, 4).Individuals also vary in their approaches andresources to compensate for declining functionalabilities. In addition, some chronic conditions mayinvolve acute episodes, drastically increasing crashrisk and complicating any judgments about fitness todrive.Many chronic medical conditions are progressive,such as Parkinson’s disease. A medical condition inits early stages may not affect driving safety but maycompromise it at a later stage. Some older driversmay have comorbid medical conditions—that is,more than one—making it difficult to determine thespecific condition that may influence driving performanceand crash risk.Similar difficulties arise in establishing the relationshipbetween medication use and crash risk.Medications can impair driving for any age group,but medication use may have a greater effect on olderdrivers. Older people are more likely to use severalmedications, may not metabolize a medicinal compoundquickly, and may experience adverse changes(5). Their use of medications also may be inappropriate—under-and overutilization of medicationsare common among older adults.Older adults also frequently consume over-thecountermedications, herbal supplements, and alcoholalong with their prescription medications. Themedical conditions and the timing and strength of adose can complicate the task of relating trafficcrashes to medication use.Reformulating the ProblemResearchers have begun to reformulate the problem,as shown in Figure 1 (1, 6). According to this model,all driver behavior is influenced by individual characteristicsand functional abilities. Individual characteristicsencompass a range of factors, including a driver’stolerance for risk, behavioral adaptations, preferences,personality, and driving history. Functional abilitiesrefer to the perceptual, cognitive, and psychomotorabilities needed for everyday activities (7).The interaction between medical conditions andthe medications used in treatment—both the therapeuticeffects and the side effects—have an impact ona driver’s functional abilities. A driver’s health conditions,treated or untreated, also influence functionalabilities. Properly treated conditions canimprove functioning, but untreated or mistreatedPHOTO: SULPHUR SPRINGS SENIOR CITIZENS CENTER, TEXASconditions can have deleterious effects.The levels of functional abilities affect the skillsneeded for safe driving. Individual characteristics andthe ability to perform critical driving skills influencecrash risk. This formulation does not require specificinformation about medical conditions or medications,but about the levels of functional abilities.Continuing Safe DrivingLike most drivers, older people tend to prefer a personalautomobile for their mobility needs; few satisfactorynondriving options are available in mostlocations. Five promising approaches for meetingthis goal include driving evaluation, education andrehabilitation, vehicle design and modification,advanced technology, and roadway design.Driving EvaluationTo help older adults continue to drive safely, knowingwhich drivers are at increased risk for a crash iscritical. Driving evaluation consists of screening andassessment.Screening is the first step, identifying potentiallyhigh-risk drivers by revealing major functionalDriver BehaviorIndividualCharacteristicsFunctional Abilities• Medical Conditions• MedicationsCritical DrivingSkills• Life Goals• Strategic• Tactical• OperationalResearchers acknowledgedifficulties in deter -mining the effects ofmedical conditions andmedications on crashrisk—not all conditionsinfluence crash risk to thesame degree, andindividuals with the samecondition differ greatlyin how they are affected.FIGURE 1 How medicalconditions andmedication can influencecrash risk [adapted fromEby et al. (1)].CrashRiskTR NEWS 264 SEPTEMBER–OCTOBER 200915

likelihood, they often lack the information necessary tomake informed fitness-to-drive decisions; they do notwant to breach physician–patient confidentiality; andthey do not want to develop a reputation for reportingdrivers, which could lead to a loss in patients; moreover,state laws on physician reporting and immunity areinconsistent.TR NEWS 264 SEPTEMBER–OCTOBER 200916Driving simulators can beused to improve, refine,extend, and test drivingskills.Programs such as CarFit,which helps seniors find avehicle that fits theircomfort level and drivingability, assist the olderperson in continuing todrive by focusing onindividual capabilities.impairments. Screening also can prompt an in-depthdriving assessment but should not be used alone todetermine driving fitness. Driver assessment is anin-depth, professional investigation to determine thelevel and cause of an observed impairment and isnecessary to support decisions about whether someoneshould continue driving and under what conditions.Screening and assessment contribute to a comprehensive,multidisciplinary approach for identifyingolder drivers who may be at risk. The drivingevaluation can take place in the home or community,in a clinical setting, or at a licensing agency; each settinghas unique issues.Home and CommunityThe home and community are an ideal setting fordriver screening. Many problems with driving arefirst identified by a family member, the driver, or apolice officer. Self-screening tools are available foruse by drivers; educational programs and materialshelp families screen and talk with their older adultmembers; and educational materials help policeinteract with older drivers. Few of these packages,however, have been evaluated, and none has beenshown to improve traffic safety.Clinical SettingsPhysicians and other health professionals can assessdriving-related problems as part of general medicaltreatment and care. Identifying declines in functionalabilities early on can facilitate opportunities for treatmentand rehabilitation.If clinical testing indicates that functional abilitieshave declined to the point of compromising drivingsafety, many older drivers will stop driving voluntarilyat the advice of their physician (8). Many physicians,however, indicate that they are uncomfortable withmaking fitness-to-drive decisions and with reportingthe decisions to licensing agencies. Physicians cite severalreasons: without a test battery that predicts crashLicensing AgenciesLicensing agencies can screen and assess for fitnessto drive because older drivers must renew theirlicenses; the licensing agency has authority to denyor restrict a person’s license to drive. Drivers’ licenserenewal policies vary from state to state in terms ofthe renewal cycle, the requirements for acceleratedrenewal for older drivers, and other provisions.These policies are not based on empirical evidence,and many questions remain about an optimal policy.In addition, licensing agencies must weigh practicalityand cost, along with the potential benefits ofagency screening and assessment. For example, conductingan in-depth assessment of every driver whoreaches a certain age—as suggested by some advocatesof age-based driver evaluation—would beimpractical and expensive.Educational ProgramsEducational programs are available for older driversbut vary in scope, format, and content. Most programsfocus on awareness of functional declines andwhat they mean for safe driving. Some programscombine educational content with training—whether by computer, simulator, or on the road—tohelp participants overcome some functional decline.Other programs target an individual’s capabilities, toassist the older person in continuing to drive; theCarFit program, for example, helps people fit morecomfortably into their personal vehicles.Despite the range of programs, most have notundergone formal evaluations for improving driverskills, reducing traffic citations, or reducing crashes.By keeping fit and staying active, older drivers maybe able to extend their driving lifetimes.PHOTO: DAN BURDEN

The few educational programs that have been evaluated,however, have increased the driver’s knowledgeand awareness (9, 10); increased self-reported safedriving behaviors (11); and improved on-the-roaddriving evaluation scores (10); however, they did nothelp to prevent roadway injuries and crashes (12).RehabilitationRehabilitation may slow or reverse some functionaldeclines experienced by older adults. Fitness and cognitiverehabilitation programs, in particular, showpromise. Fitness programs that improve range ofmotion, strength, and stamina may help older driversextend their driving lifetimes. Proper and intensivecognitive training may improve cognitive functioning(13). Whether these programs can improve the cognitiveabilities to have a positive effect on critical drivingskills or to reduce older driver crash risk is not known.Vehicle Design and AdaptationCurrent vehicle designs do not take into accountmany of the functional declines associated withaging; this may not change for many years becauseof the beleaguered state of the industry. Nevertheless,little research specifically has addressed designs thatoptimize vehicles to account for age-related functionaldeclines.People who are experiencing functionaldeclines, however, can make aftermarket changes toa vehicle to ease operation. Vehicle adaptations canhelp drivers with disabilities or aging-related concernsto get in and out of the car, fasten and unfastensafety belts, and operate the vehicle more easily.Because adaptive equipment must be customized tomeet individual needs, the driver should work withan occupational therapist, who can recommend thecorrect equipment, and with a professional installer.Although custom vehicle adaptations shouldimprove traffic safety, no research has demonstratedthe benefits. Research has indicated a lack of awarenessof the options for vehicle adaptation not onlyamong many older drivers who could benefit butalso among the professionals who work with them.Advanced TechnologySeveral technologies are now available or soon willbe to help older drivers extend their safe drivingcareers. The most promising technologies includeroute guidance, night vision enhancement systems,collision warning systems, and automatic crashnotification.To be successful for older drivers, these technologieswill need to be affordable, easy to use, andenhance safe driving. Poorly designed technologiescould increase distractions for older users, leadingto a higher risk of crashes. Systems designed forolder drivers, however, would likely benefit driversof all ages.Research shows that older drivers use advancedtechnologies differently from younger drivers andthat older drivers take much longer to learn how touse the technologies (14, 15). Whether this is aneffect of not growing up with computer technologiesor of aging per se is not known. Nevertheless,the acceptance of advanced technologies by olderdrivers will depend on the quality of the trainingthey receive.Roadway DesignAnother way to enhance the safety of older drivers isto design the roadway environment to accommodatecommon age-related functional declines—for example,by adding protected left-turn signals and improvingroadway channeling, stop signs, and signal timing.Well-maintained roadway markings—such as paintededge lines and lane control marking—can enhancesafety by providing visual cues to help drivers knowwhich lane to use and to stay within the lane.In addition, design improvements at intersectionscan benefit older pedestrians who are more likelythan younger pedestrians to be killed by automobiles.Where appropriate, roundabout intersectiondesigns show promise. The circular, nonsignalizeddesign of roundabouts allows all traffic to move inthe same direction around the center of the inter-PHOTO: AVENUE INNOVATIONS INC.Research engineers atNissan test the controlsof a model; the driverwears a special restrictivesuit and other geardesigned to simulate theeffects of physical aging.Aftermarket vehicleadaptations such as theHandybar®, which fitsinto the striker plate of avehicle’s door frame andassists drivers in gettingout of their cars, canmake some aspects ofdriving easier for olderadults.TR NEWS 264 SEPTEMBER–OCTOBER 200917

Driving ChangeThe Safety and Mobility Patternsof Older Women in 2030Defining and Meeting the ChallengesSANDRA ROSENBLOOM AND SUSAN HERBELRosenbloom is Professorof Planning, Universityof Arizona, Tucson, anda member of the TRBExecutive Committee.Herbel is a Principalwith CambridgeSystematics, Inc.,Heathrow, Florida.Research shows thatwhen riding in a privatevehicle, older women aremuch less likely to bedriving than are oldermen.Older women are the most likely travelersof any age to die in car or pedestriancrashes. The National Highway TrafficSafety Administration has concludedthat unless something is done, these fatality rateswill double or triple by 2030 (1). In addition, thedriving restrictions that older women adopt are farmore likely to have a negative impact on their mobility.Even when they are healthy and continue to besafe drivers, older women are substantially morelikely than comparable men to stop driving completely.More than three-fourths of all older people live insuburban and rural areas—the vast majority of olderwomen therefore are living in places in which a caris a necessity. Older women also are substantiallymore likely to live alone, to be poor, and to lackretirement income other than Social Security.Older women today must make a complicatedchoice—to continue to drive and face an increasedrisk of serious injury or death or to restrict or ceasedriving and face the even greater risk of social andemotional isolation. If these trends continue, whatcan be done so that no one has to face this intolerabledilemma? Examining the many differences in thePHOTO: AAA FOUNDATION FOR TRAFFIC SAFETYtravel behavior of older women and men can help indeveloping needed policies.Differences in Travel BehaviorAt all ages, women today have patterns of licensing,trip-making, and modal choices that differ fromthose of comparable men. Some of the gender gap isclosing among younger generations of travelers butis far from disappearing. Many of the differences seenbetween older people today may continue into thenext two decades.In 2006, almost 30 million Americans over 65years of age had a driver’s license. Older women,however, were far less likely to be licensed than comparablemen; in the over-65 age group, 91 percent ofall men but only 71 percent of all women had alicense. Many women now over the age of 80 neverlearned to drive. But the licensing gap betweenyounger cohorts of older people may reflect thegreater likelihood that older women will stop drivingat younger ages than comparable men.Many studies have associated increased licensingwith substantial increases in all aspects of travel forolder and younger travelers alike. Between 1983 and2001, licensing rates for older women increased by50 percent, compared with only a 7 percent increasefor men. Although men and women traveled substantiallymore in 2001, the increases were generallygreater among women than among men.Older women and older men drivers make theoverwhelming portion of all their trips in a car, eitheras the driver or as the passenger. Neither groupmakes more than negligible use of public transit orof other modes of travel.But riding in a private vehicle and driving thevehicle are two different activities. In 2001, whenolder women drivers traveled in a private vehicle,they were substantially less likely to be driving thanwere comparable men. The tendency to be the passenger,not the driver, was highest at the oldest ages.Almost two-thirds of male drivers over the age ofTR NEWS 264 SEPTEMBER–OCTOBER 200919

TR NEWS 264 SEPTEMBER–OCTOBER 200920AARP offers an onlineDriver Safety program.Some research has found,however, that olderwomen responddifferently fromcomparable men to olderdriver training programs.85—but only one-fourth of comparable womendrivers—drove the vehicle in which they were riding.Self-Regulation and FeelingsAbout DrivingOlder people are not risk-takers—they recognize thatas they age, they may experience problems in driving,and they change their behavior in response. Butolder men and women exhibit substantial differencesin almost every aspect of self-regulation.Women and men find different kinds of situationsto be problematic. Women are far more likelyto find that driving situations have become difficultand to change their travel behavior; they are also farmore likely to say that the change in their travelbehavior has affected their mobility negatively. Themost common form of self-regulation among olderwomen is to cancel a trip when problems arise.Women drivers are substantially more likely tofind driving stressful and to express a lack of confidencein their driving abilities, even if they are objectivelygood drivers. This leads them to drive lessoften, which in turn reduces their confidence andincreases their levels of stress—to which theyrespond by driving even less.Paradoxically, driving less may have a negativeimpact on driving safety as well as mobility. Crashrates are related to the amount of driving. Whencrash data are controlled for level of exposure, mostresearchers find that the age effect in crash rates disappears.Crashes are overrepresented among peoplewho do not drive very much, regardless of age.This finding reinforces the dangers associatedwith women reducing their driving significantly.Although baby boomer women may drive morewhen younger, and therefore be more confident asdrivers when older, the Federal Highway Administrationhas predicted that if 2001 patterns continue,the mileage gap between older women and men willwiden over the next four decades (2).Response to Safety andEducational MessagesNHTSA found that women younger than 65responded differently to messages about drivingsafety than did comparable men; the study concludedthat younger women needed different safetymessages from those addressed to middle-agedwomen (3). Tuokko et al. concluded that educationalmaterials for older drivers had to be targeted differentlyfor women and men, because women weremore willing to change their behavior, more consistentin their attitudes toward regulations, and usedsafer driving practices (4).Some research has found that older womenrespond differently from comparable men to olderdriver training programs. A study of the AARP DriverSafety Program found that women participants weremore likely to report that their driving skills hadimproved (5). Rosenbloom found that 1 year afterparticipating in a variety of safety education programsin Tucson, Arizona, older women were more likely torespond that they did not engage in as much self-regulationas comparable men or as a control group ofwomen who did not participate in the programs (6).At a minimum, these findings suggest that thesafety messages and educational techniques currentlyin use may have different impacts on women andmen. But the findings also may suggest that olderdriver education programs may give competentwomen drivers a better idea of the strength of theircurrent skills.Driving CessationMost research shows that older women give up drivingvoluntarily at younger ages than comparable menand for less serious reasons. When older womencease to drive, they are much less likely than men tocite medical or health reasons. In a Tucson study,more than 90 percent of men, but only 46 percent ofwomen, who stopped driving during the studyreported the causes as serious medical or vision problems.Almost 18 percent of the women who stoppeddriving said that they “couldn’t deal with the stress.”None of the men gave that answer.Married people are more likely to stop drivingthan those who live alone—but the effect is far morepronounced among women, who constitute theoverwhelming number of unmarried older people.This suggests that older women who have a spousewho drives are more likely to cease driving.The long-term implications of this decision can betragic. In several studies, women who had ceaseddriving but subsequently lost their driving spouse todeath or disability expressed regret that they hadgiven up driving. Johnson found that older rural res-

idents who voluntarily stopped driving often had toresume because their social networks were not ableto meet their mobility needs (7).Driving cessation among older women is aresponse to a complicated set of factors, including alack of confidence and the stresses of driving. Evidenceis growing, however, that older women also arefar more responsive to criticism of their drivingskills—whether the criticism is valid or not—thanare comparable men. Older women may lack confidencein their driving because their spouse directlyor indirectly disparages their driving performance;several studies have reported many situations inwhich older women were discouraged from drivingby their partners (3, 8–10).Safety Statistics and TrendsOlder drivers consistently have lower fatal crash ratesper capita than those 21 to 64 years old. When thecrash rates are based on exposure, however—thatis, on the number of miles traveled—the crash riskincreases for older drivers. Those 85 years old andolder have the same crash rates per mile driven asthose 20 to 24 years old (11). These travel indicatorsalso reveal important differences between olderwomen and men.On a per capita basis per 100,000 of the population,older women were one-third as likely as oldermen to be involved in a fatal crash, according toupdated 2005 data (12). In 2005, older men were alarger component of fatalities in the age group of 65and older than in 1995. In contrast, between 1995and 2005, the absolute number of crash fatalitiesamong older women fell—often significantly—although the total population of women over age 65increased by almost 12 percent.Despite some positive trends in the data, olderwomen and men constituted a larger share of crashesthan they did of the U.S. population. In 2006, womenover 65 accounted for 13.6 percent of all women butrepresented 20.8 percent of all female crash fatalities—thehighest proportion of fatalities for any populationgroup.Ferguson and Braitman found that total crashinvolvement—whatever the outcome—and fatalcrash involvement move in opposite directions (13).On a per capita basis, the fatal crash rate increases aspeople age; however, at all ages, the rate of total crashinvolvement was lower for women than for men. In2003, almost 50 fatal crashes per 100,000 driversinvolved men who were 85 years old or older, butonly 20 involved comparable women.Controlling for exposure, or miles driven, however,fatal crash involvement for drivers rises sharplyafter age 70 for men and women, with little difference.By age 85, both men and women drivers hadthe highest rate of fatal crash involvement among alldrivers per 100 million miles traveled. Ferguson andBraitman found that total crash involvement per millionmiles traveled also rose after age 65, but far fasteramong men than among women (13). Althougholder women had fewer crashes per capita than oldermen, older women were far more likely to die in thecrashes in which they were involved.Research and Policy ImplicationsMost experts agree that developing a range of policiesand programs to improve the safety and themobility consequences of an aging society is necessary,by addressing the following:u The driving and pedestrian environment,including a focus on the driver, the vehicle, and theroad network;u The public transit network, including initiativesto improve the quality and to increase the quantity;to modify as appropriate the serviceprovided—encompassing new or less traditional serviceand better travel information, personal security,safety, and accessibility; and to improve the vehiclesand the training of drivers;u Alternative transportation systems, includingenhancements to the quality and the quantity of service,to the coordination between and amongproviders, and to dispatching programs, geographicinformation systems applications, driver training,vehicles, the effective use of volunteers, andexpanded use of voucher systems; andu Neighborhood design, including the developmentof intergenerational and elderly-friendly citiesthrough community design, land use regulations,traffic enforcement, enhancement of personal security,and education, as well as alternative housingoptions for aging-in-place populations, new communities,and formal and informal active adult retirementcommunities.Women make up amajority of transit andspecial transportationusers; suggestions forimprovements totransit and specialtransportation orparatransit alternativesmay address the needs ofwomen.TR NEWS 264 SEPTEMBER–OCTOBER 200921

PHOTO: ITNAMERICAmen differ in how they receive and process educationalmessages about safety and safe driving behavior,more research is needed to investigate ways totarget safety programs to older women. Researchbasedguidance is needed on the most effective waysto prepare training and education programs, mediamessages, and incentives to encourage women tokeep driving safely as long as possible.TR NEWS 264 SEPTEMBER–OCTOBER 200922Many community-basedprograms provide ridesfor seniors but are notable to meet the fullscope of needs, accordingto a study; Martha Giles(left), a volunteer withthe Portland, Maine,affiliate of the nonprofitIndependentTransportation Network,has logged more than70,000 miles on localassignments.The extent to which these types of improvementswould meet either the differential or special safety ormobility needs of older women is unknown. The differencesidentified between women and men in somany aspects of travel and transportation, however,lead to questions about the applicability of one solutionto meet the needs of women and men equally.Improving the DrivingEnvironmentMost research on improving the skills of older driversand pedestrians does not distinguish betweenfemales and males. Almost everything that improvessafety and mobility for all older travelers will workfor older women. Nonetheless, older women mayhave safety and mobility needs that are increased ordifferent compared with those of older men.Research and policy analysis therefore need to focuson these differences, as well as on measures that havea positive effect on women and men as they age.Strategies to improve the driving environment orthe vehicle often draw no distinction between thesexes. Older people have trouble with lane markings,signs, and directional messages; whetherwomen and men exhibit important differences inthese tasks is not known; if differences are found,programs need to respond and adapt accordingly.Similarly, information is lacking on how womenand men respond to different kinds of safety belts,crash avoidance systems, and other in-car equipment.Older women experience more stress whendriving and are more vulnerable in crashes, but studieshave yet to determine specific vehicle componentsthat may improve crash protection forwomen—who tend to be of smaller stature and havedifferent body characteristics—or that may contributeto a less stressful driving experience.Although some research shows that women andPublic Transit andSpecial AlternativesA large body of research has outlined the improvementsneeded in traditional public transit systems andspecial services for older adults. Since almost 9 out of10 transit and special transport users over age 65 arewomen, many of the research or policy suggestions forimproving transit and special transportation or paratransitalternatives may address women’s specific publictransit needs, which range from improved personalsecurity at stops and on board to the restructuring ofroutes to serve preferred origins and destinations. Theextent to which women and men may differ in theirresponses to specific improvements or services, however,is not known.Many older women and men live far from publictransit services, and if available, the services often aredesigned for commuters. Substantially increasing thequantity and the quality of public transit servicesand of alternative services is important. Many federalprograms fund special services, and every communityhosts different kinds of providers—some programsfacilitate volunteers providing rides, and somelarge systems offer special vehicles and paid drivers.A study for the Institute of Medicine, however,found that even taken together these providers wereunlikely to offer an average of more than three tripsa year to each older person with disabilities in theircommunity (14). Moreover, many of these providerstended to limit severely the kinds of trips theyserve—for example, allowing only medical trips oragency trips—so that eligible older people must findother means for social, recreational, or grocery trips.Neighborhood DesignMany different kinds of land use and planningchanges could create communities that facilitatewalking or using public transit instead of relying onthe car, thus enhancing older people’s health, as wellas their mobility. Some research, however, suggeststhat these land use changes also may make communitiesbusier and more active in ways that can bedetrimental to older people, and particularly to olderwomen; moreover, that women and men perceivemany design components of the environment differentlyand therefore modify their travel patterns dif-

SPECIAL FEATURECommunicating Transportation, Energy,and Climate Change Conceptsto the PublicTRB Contest Identifies Exemplary EffortsJUDY A. MEYER AND JENNIFER L. WEEKSTR NEWS 264 SEPTEMBER–OCTOBER 2009Meyer owns and operatesPublic InformationAssociates, Allen, Texas.Weeks is a ProfessionalAssociate and SeniorSupervising Planner,Parsons Brinckerhoff,Baltimore, Maryland,and chairs the TRBPublic Involvement inTransportationCommittee.The contest-winningentry, Transportation-Town.com, features aninteractive game thatfacilitates collaborativedevelopment of a visionfor transportation, landuse, and growth inWhatcom County,Washington.Transportation professionals often find thatcommunicating critical transportationconcepts to a nontechnical audience is achallenge. Some have assembled tools,graphics, or the right words to convey their message,but opinion research indicates that transportationprofessionals face a largely uninformed public.Communicating and building relationships withthe people who rely on a variety of transportationmodes to live, work, and play is a relatively new task.The Roman builders of the famous roads and aqueductsmay not have spent a lot of time communicatingwith senators, nobility, or common citizens todetermine a project’s need, location, or design. Whenthe Wright brothers took their first flight, the conceptsof a Part 150 noise study or of airspace minimumsdid not yet exist.Today, expectations are different. The transportationsystem is a complex network of roads, bridges,railroads, airports, services, ports, and more, affectingeverything from the economy to the environment.Federal transportation law and regulationsrequire state departments of transportation (DOTs),metropolitan planning organizations, and transitagencies to consult with and involve a variety ofstakeholders in decision making. Federal decisionmaking about transportation is littered with laws andregulations that affect technical decisions about thedelivery of transportation improvements and services.Successfully engaging stakeholders requiresthe effective communication of a myriad of issuesand relationships throughout the entire decisionmakingprocess—from the initiation of a long-rangesystem plan to project construction to system operationsand maintenance.Not only have the rules become more complex,but the public’s levels of education, sophistication,and engagement with the world have increased. Thepublic expects the effective communication of theconcepts, principles, and purposes of transportation—communicationis critical for the community’sunderstanding and acceptance of transportationdecisions.Seeking Successful MethodsIn 2007, the Planning and Environment Group ofthe Transportation Research Board (TRB) launched acompetition to stimulate fresh and creative methodsof communicating technical transportation issues andconcepts to John and Jane Q. Public and to share themethods that have proved successful. The target audiencesfor the communications range from elementaryschool children to adults living in retirement communities,as well as elected officials, business owners,and commuters. To ensure that entries meet theambitious objective of communicating with all possibleaudiences, the competition judges are drawnfrom a range of professional backgrounds, includingschool teachers, journalists, administrative assistants,and transportation professionals.The contest has proved a great success. More than70 entries were submitted to TRB in a range of communicationmedia. TRB Executive Director Robert E.Skinner, Jr., presented awards to 11 entries in a specialposter session at the 2008 TRB Annual Meetingin Washington, D.C. With the overwhelmingresponse from contest participants and the interest24

piness of the citizens and allow players to monitortheir progress and see the effects of their decisions.The entry was developed by the Whatcom CountyCommunity Advisory Group, represented at theAnnual Meeting poster session by Melissa Miller,Whatcom Council of Governments, Bellingham,Washington. The website is located at www.transportationtown.com.Melissa Miller, Whatcom Council of Governments,Bellingham, Washington, with the poster display ofTransportationTown.com, which included acomputer demonstration.shown by attendees, TRB has made the contest anannual event, addressing a different transportationissue or theme each year to provide variety for thecontest and to appeal to different groups within thetransportation industry.This past year’s competition focused on energyand climate change in transportation, the spotlightthemes of the TRB 2009 Annual Meeting. The selectionof a hot topic within the transportation industryyielded a small, but focused, set of entries,ranging from a book to multimedia presentationsand interactive online games.The quality of the entries demonstrates the talentwithin the industry for communicating complextechnical concepts to the layperson. The entries epitomizedthe goal of communicating complex informationin an uncomplicated manner. TRB designatedone winner and four finalists.Contest WinnerTransportationTown.com: A Regional TransportationWebsite, the winning entry, aims to engage andeducate visitors about transportation in WhatcomCounty, Washington. The site targets citizens seekinginformation about various modes of transportation,with links provided for each mode. The homepage presents regionally relevant information aboutland use, transportation, and multimodal planning.An interactive game invites visitors to build a cityby placing icons on a map. Within a set amount oftime—representing 1 year—players make decisionsabout relationships between land use and transportation;the results are then displayed. The gamevisually demonstrates how the player’s decisionsaffect air quality, mobility, and city appeal; the relativevalues of investment in transportation modesalso are shown.The goal of the game is to build a prosperous citythrough land use and transportation decisions thatkeep mobility high, pollution low, and the citizenshappy. Dials track pollution, mobility, and the hap-FinalistsTransport Revolutions: Moving People andFreight Without OilTransport Revolutions: Moving People and FreightWithout Oil, a 2008 book by Richard Gilbert andAnthony Perl, traces out several revolutions—defined as major changes in how people and freightmove—in the coming decades in transportation.These changes will be the result of declines in worldoil production and rises in the prices of oil products.The authors, who are with the Urban Studies Programat Simon Fraser University, Vancouver, BritishColumbia, Canada, examine past revolutions anddescribe transportation and its impacts today. Theynote that the United States and China can accommodateoil depletion without reducing mobility. Forexample, by 2025 electric traction of various kindscould propel more than 30 percent of surface transportationin the United States. The book alsodescribes the coming revolutions in aviation andmarine transportation.Drive $marter ChallengeThe Drive $marter Challenge, an interactive websiteof the Alliance to Save Energy, Washington, D.C.,served as a call to action as part of a multimediacampaign to promote fuel efficiency. The website,assembled by Ronnie Kweller and Rozanne Weissmanat www.drivesmarterchallenge.org, shows howhuman actions have a ripple effect on fuel consumptionand emissions.Drivers can find out immediately how muchmoney they can save—often hundreds of dollars—through six driving and maintenance actions ontheir own vehicles, by specificmake, model, and year. Driversthen can decide whether totake the challenge and committo any one of six actions,and they can challenge othersto make the commitment aswell.Individual savings—dollars,gallons, and carbon dioxideemissions—are added tothe running total, recorded onCover of the paperbackedition; the bookexplores the worldwidetransition from oil-basedfuels.The Drive $marterChallenge website allowsparticipants to enterinformation about theircar make, model, andyear, obtain an annualsavings total by applyingsix maintenance actions,and receive energysavingtips on driving andautomobile maintenance.TR NEWS 264 SEPTEMBER–OCTOBER 200925

the home page, of all who have taken the challenge.The website also offers money-saving gas tips in Englishand Spanish, related resources, and mythbusters—objective information that contradicts popularmisconceptions.TR NEWS 264 SEPTEMBER–OCTOBER 2009A screen from the CD-ROM developed by NewJersey DOT and ParsonsBrinckerhoff depictsoptions and outcomesfor work-to-store travelunder smart growthand sprawl; thedemonstration illustratesthe complex relationshipsbetween land use andtransportation.Your Community—Smart Growth Versus Suburban SprawlNew Jersey DOT and Parsons Brinckerhoff developedthe interactive CD-ROM demonstration, YourCommunity—Smart Growth Versus SuburbanSprawl, to support the agency’s educational efforts tointegrate transportation and land use. Part of NewJersey DOT’s Long-Range Plan 2030 outreach program,the demonstration consists of a series of tripsthrough two hypothetical communities. One communityreflects smart growthapproaches, with integratedland use and a multimodaltransportation system; theother reflects suburbansprawl, with isolated landuses that require travel by privateautomobile.Trips to school, work, andother destinations are showngraphically, with a summaryof miles traveled by automobile,transit, or walking, plusa comparison of time spentfor each commute. Points areawarded for efficiency and qualitative health andenvironmental benefits. The interactive programdemonstrates the potential environmental, health,convenience, and time advantages of smart growth,educating people to make choices that reduce theircarbon footprint.The project team included James B. Lewis andDanielle Graves, New Jersey DOT; Jerome Lutin, formerlyof New Jersey Transit; and Pamela M. Lebeauxand Marc Steuben, Parsons Brinckerhoff.BWC and Climate Change:Making the ConnectionThe Best Workplaces for Commuters (BWC) designationis the national emblem representing outstandingcommuter benefits. Millions of commuterswho work at BWC-designated worksites leave theircars at home, easing congestion and air pollutionand reducing greenhouse gas (GHG) emissions.The interactive program, BWC and ClimateChange: Making the Connection, assembled by IanTodreas of ERG, Boston, Massachusetts, aims to helpemployers make and broadcast the connectionbetween transportation demand managementThe Best Workplaces for Commuters (BWC)campaign shows employers how commuter benefitscan play a significant role in mitigating some of thecauses of climate change. Ian Todreas, ERG, Boston,Massachusetts, provided a review of the BWCwebsite and its features at the TRB 2009 AnnualMeeting.(TDM) and climate change. Users leverage newopportunities to position BWC—and more generally,commuter benefits—as a near-term, cost-effectivesolution to climate change.The website features national and state-specificinformation about climate change; state-specificinformation on climate and TDM policies, players,and funding sources; local, state, regional, andnational climate and transportation organizations;and funding sources that might be available to supportTDM as a climate change solution. The websitecontains messages and talking points on how to promotelocal and regional BWC programs as a climatefriendlyTDM solutions and how the climate benefitsof BWC compare with those from other transportationstrategies. The website also has links to tools tomeasure the impact of climate change strategies.What’s on Tap for 2010The contest to be featured at the TRB 89th AnnualMeeting, January 10–14, 2010, focuses on communicatingabout issues related to providing and operatingpublic transportation. The purpose is to tacklethe challenges of communicating the role of transitin the larger transportation system, as well as uniquetechnical issues such as transit operations and maintenance,costs and financing, and transit projectdelivery, including the Federal Transit Admini -stration’s complex New Starts process. The entriesshould help agencies remove the mystery from publictransit for everyone from elected officials to thetraveling public.26

RESEARCHPAYS OFFService Life ModelingSelecting Repair and Rehabilitation Optionsfor Bridge StructuresALI AKBAR SOHANGHPURWALA AND IVAN R. LASASohanghpurwala is President,CONCORR, Inc.,Sterling, Virginia; andLasa is Corrosion Mitigationand RehabilitationTechnologist, CorrosionResearch Laboratory,Florida Department ofTransportation,Gainesville.View of one of the examinedbridges on I-95 nearBangor, Maine, showingcracking caused by reinforcementcorrosion. Conditionevaluation includeda delamination survey,cover depth measurements,chloride ion contentanalysis, andpetrographic analysis.Evaluating the corrosion condition of areinforced concrete structure is essentialin developing a strategy for repair andrehabilitation after corrosion-induceddamage. Several destructive and nondestructive testmethods and techniques are available to ascertainthe corrosion condition of the reinforcement in portionsthat do not yet show concrete damage. Most ofthese techniques, however, require significantresources to implement and then additionalresources to interpret the data and make the decisionsabout repair and rehabilitation.The National Cooperative Highway Research Program(NCHRP) therefore initiated a project todevelop a protocol for evaluating the condition ofbridge superstructure elements, for estimating theremaining service life, and for identifying the optionsfor mitigating the corrosion. The project findings,published in 2006 in NCHRP Report 558, Manual onService Life of Corrosion-Damaged Reinforced ConcreteBridge Superstructure Elements, produced a conditionsurvey protocol, a model for remaining servicelife, and a susceptibility index to designate the likelihoodof corrosion.ProblemThe National Bridge Inventory database, maintainedby the Federal Highway Administration, contained atotal of 587,964 bridges as of 2002. The average ageof the bridge structures in the database is 40 years;41 percent of the bridges are at least 40 years old.The condition of the nation’s aging highwaybridge infrastructure has gained significant attentionin the past two decades. Several independent evaluationsof the condition of the nation’s infrastructurehave used the ratings in the database. These studiesascertained that 14 percent of the bridges were ratedstructurally deficient and that the primary cause ofthe deficiency was corrosion of the reinforcing steel.For the 20-year period from 1999 to 2019, the estimatedcost of maintaining the nation’s bridges is $5.8billion per year, and the estimated cost of improvingthe same bridges and eliminating their deficiencies is$10.6 billion.To address deterioration from corrosion, a bridgeowner must decide whether to maintain, repair, orreplace the structure, considering its present conditionand its expected condition. The owner also mustidentify the materials and methods that are mostappropriate to the task. Because of the lack of standarddecision-making processes, most owners havemade these complex decisions by relying on localexperience and expertise. These decision-makingprocesses often have resulted in inefficient, costly,nonstandard, and nonoptimal solutions.A protocol capable of determining the optimalcourse of action—maintenance, repair, or replacement—andof assisting in the selection of the bestmaterials and methodology was urgently needed.SolutionDetermining the optimal course of action requiresinformation about the present condition of the structureand its expected deterioration. The present conditiondetermines the quantity and the type of repairsnecessary. The owner can use the expected futuredeterioration to determine the efficacy of alternativerepairs and to assist in selecting a repair-and-TR NEWS 264 SEPTEMBER–OCTOBER 200927

TR NEWS 264 SEPTEMBER–OCTOBER 200928prevention strategy to minimizethe cost of maintenancefor the period of service lifedesired from the structure.The future corrosion activitycan be projected either fromthe estimated remaining servicelife of the structure or as afunction of the concrete deteriorationcaused by the corrosionof the reinforcement. Theremaining service life methodrequires the owner to formulatea criterion to define theend of the service life. Theother approach, applying afunction of concrete deteriorationover time, provides theowner with scientific data onthe progression of damage andfacilitates identifying the typesand timing of the most appropriate actions. TheNCHRP project chose the second approach, which ismore flexible. For simplicity and to conform to thenaming convention in the literature, the projecttermed the process “service life modeling.”Although several mathematical methods havebeen proposed to model the corrosion processaccording to the extent of deterioration and the presenceor absence of deleterious agents, none has beenfound to be comprehensive, verified scientifically, orstandardized for the bridge community. The modeldeveloped in the NCHRP project, however, was statisticallyvalidated on three bridge structures in Kentucky,Ohio, and Maryland.The model requires results from a delaminationsurvey, a few cores for chloride profile analysis, andclear concrete cover data. A susceptibility index, basedon the distribution of chloride ions in sound concrete,narrows the options available for corrosion control.Manual DescribesProtocolsNCHRP Report 558, Manualon Service Life of Corrosion-Damaged Reinforced ConcreteBridge SuperstructureElements, presents the findingsof a research project conducted by CON-CORR, Inc. The manual offers step-by-stepprocedures to assess the condition of corrosiondamagedbridge elements. Also included areprocedures for estimating the expected remainingservice life of reinforced concrete bridgesuperstructure elements and to determine theeffects of maintenance and repair options on astructure’s service life. The report is availableonline at http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_558.pdf.ApplicationsFlorida has applied the model on several bridgestructures. On the I-75 bridges over the CaloosahatcheeRiver and the Tidal Marsh in Fort Meyers,Florida, a consultant used the results of service lifemodeling to recommend widening of the bridgeswith repairs instead of a complete replacement, producinga considerable savings for the state. The servicelife modeling provided confidence in the optionof widening and repairs by providing a clear view ofexpected future damage.The model also was used on the Courtney CampbellBridge in Tampa to ascertain the magnitude of thecorrosion problem and the options available for repairand rehabilitation. The model was applied recently forthe historic North Torrey Pines Road Bridge, in DelMar, California, to determine the best options forrepair and rehabilitation of the substructure elementswhile maintaining the historical characteristics.Other applications include the substructure elementsof four bridges on I-95 near Bangor, Maine;piers of the Military Ocean Terminal, Sunny Point,North Carolina; piers of the Port of Moorehead City,North Carolina; and the terminal used by Alcoa inCharleston, South Carolina. In each instance, use ofthe model has resulted in the optimal design ofrepairs and of corrosion control systems.BenefitsThe model and the susceptibility index provide astreamlined mechanism for performing the corrosioncondition survey and applying the survey resultsto determine the future progression of damage andto select the optimal repair and corrosion controlsystem. The service life model allows the owner toperform life-cycle cost analyses of various optionsaccording to estimates of the progression of damage.Service life modeling offers another advantage,by reducing the amount of field data collection andsampling. The model requires only the results of thedelamination survey, chloride profile analyses, and aconcrete clear cover survey.The condition evaluation protocol of this modelcan be integrated easily into the routine bridgeinspection. In addition, the model can be used toascertain future susceptibility to corrosion-induceddamage and the magnitude of the damage, so that theoptimal corrosion control systems can be installed toreduce or stop corrosion and increase the remainingservice life.For more information, contact Ivan R. Lasa, CorrosionResearch Laboratory, Florida Department of Transportation,50057 NE 39th Avenue, Gainesville, FL32609; 352-955-2902; ivan.lasa@dot.state.fl.us; or AliAkbar Sohanghpurwala, CONCORR, Inc., 45710 OakbrookCourt, Sterling, VA 20166; 571-434-1852;ali@concorr.com.EDITOR’S NOTE: Appreciation is expressed to AmirHanna, Transportation Research Board, for his effortsin developing this article.Suggestions for “Research Pays Off” topics are welcome.Contact G. P. Jayaprakash, TransportationResearch Board, Keck 488, 500 Fifth Street, NW,Washington, DC 20001 (telephone 202-334-2952,e-mail gjayaprakash@nas.edu).

C A L E N D A RTRB MeetingsNovember12–13 Developing a ResearchAgenda for TransportationInfrastructure Preservationand RenewalWashington, D.C.16–18 5th National Transit GISConference*St. Petersburg, FloridaThomas PalmerleeDecember13–15 Transportation Policy andFinance Summit*Washington, D.C.13–18 12th InternationalConference on TravelBehavior Research*Jaipur, IndiaKimberly Fisher2010January10–14 TRB 89th Annual MeetingWashington, D.C.www.TRB.org/AnnualMeetingMarchTBDAprilRoad Safety on FourContinents Conference*Abu Dhabi, United Arab Emirates12–16 1st International Conferenceon Pavement Preservation*Newport Beach, California27–29 High-Speed and IntercityPassenger Rail Systems andStrategies Joint RailConference*Urbana, IllinoisElaine KingAdditional information on TRB meetings, including calls for abstracts, meeting registration, and hotel reservations, is available atwww.TRB.org/calendar. To reach the TRB staff contacts, telephone 202-334-2934, fax 202-334-2003, or e-mail lkarson@nas.edu.Meetings listed without a TRB staff contact have direct links from the TRB calendar web page.*TRB is cosponsor of the meeting.May5–7 1st International Conferenceon Nanotechnology inCement and ConcreteIrvine, California9–12 Innovations in Travel DemandForecasting: 2010Tempe, Arizona13–14 Innovations in Pricing ofTransportation Systems:Workshop and Conference*Orlando, Florida19–21 Transportation Finance:Forging a SustainableFuture—NowNew Orleans, Louisiana30– Safety and Mobility ofJune 2 Vulnerable Road Users:Pedestrians, Motorcyclists,and Bicyclists*Jerusalem, IsraelRichard PainJune2–4 TRANSED 2010: 12thInternational Conference onMobility and Transport forElderly and Disabled People*Hong Kong, China2–5 4th International Symposiumon Highway GeometricDesign*Valencia, Spain3–5 GeoShanghai 2010International Conference*Shanghai, China6–10 Environment and Energy inTransportation Summit*Raleigh, North Carolina21–24 North American TravelMonitoring Exposition andConference (NATMEC):Improving Traffic DataCollection, Analysis, and UseSeattle, WashingtonThomas PalmerleeJuly11–14 49th Annual Workshop onTransportation LawNewport, Rhode Island11–14 TRB Joint Summer MeetingMinneapolis, Minnesota11–15 5th International Conferenceon Bridge Maintenance,Safety, and Management*Philadelphia, PennsylvaniaSeptemberTBDOctoberInternational Conference onSustainable ConcretePavement Technologies:Practice, Challenges, andDirections*California10–13 9th National Conference onAccess Management*Natchez, Mississippi25–27 6th International Conferenceon Visualization inTransportationTBDRichard Pain26 Using National HouseholdTravel Survey Data forTransportation PolicyDecisionsWashington, D.C.TR NEWS 264 SEPTEMBER–OCTOBER 200929

P R O F I L E S. . . . . . . . . . . . . . . . . . .Johanna ZmudNuStats, LLC“Our data assetsmust align to currentconditions and, moreimportantly,anticipate emergingchallenges.”All transportation researchers will be involved, atsome point, in data collection. As president ofNuStats, LLC—a survey science consultancy basedin Austin, Texas—Johanna Zmud spends much ofher time improving data collection methods to meet transportationobjectives. “The traditional responses to the challengesof transportation safety, congestion mitigation, andenvironmental protection involve infrastructure or equipment.Improving our understanding of people’s travel behavior—thehow, why, when, and where they choose to travel—is at least asimportant for sound policy and planning,” Zmud observes.Zmud cofounded NuStats 25 years ago to bring rigorous andcutting-edge survey research techniques to the study of transportation,health, education, the environment, and public safety.In the late 1980s, she perceived a need for a solution to travelbehavior measurement challenges within the survey science tradition,and guided NuStats to fill that gap. Zmud sought toimprove the quality of the data available for decision making,with a focus on linking transportation planning and sound surveyscience. NuStats is now the largest producer of primarytravel behavior data in the United States.In a 2007 TRB transportation data needs assessment withJoseph Schofer, Tim Lomax, and Tom Palmerlee, Zmud coinedthe phrase “data as an asset.” Because of increasing requests frompolicy makers and new legislative reporting requirements, thedemand for data exceeds the supply. The value of the data assetmust be recognized, invested in, and prudently managed, Zmudobserves: “Our data assets must align to current conditionsand—more importantly—anticipate emerging challenges suchas climate change or new technology, changing demographics,land use, or different options for financing transportation.”Zmud notes, however, that the transportation data infrastructureis “the most neglected asset in our transportation balance sheet,despite its potential for improving people’s lives.”Although Zmud’s training is in the social sciences, almost allof her professional career has been in the transportation researcharena. Zmud received a bachelor’s degree in foreign languagesfrom East Carolina University, with master’s degrees specializingin educational statistics from the University of Maryland andin communication management and policy from the Universityof Southern California (USC). She received a PhD in communicationresearch from USC’s Annenberg School.Zmud’s theoretical and technical social science backgroundcomplements a growing expertise in transportation policy andplanning issues. In addition to her responsibilities as presidentof NuStats, Zmud continues to direct large-scale travel surveysas a way to monitor and refine her firm’s performance and leadershipin the field. As Zmud explains, “NuStats operates with thevision of continual improvement—reinventing research techniquesand approaches dynamically as circumstances change.”She has been instrumental in leading the practice in applyingnew technologies to capture an expanding set of data requirementsmore quickly and cheaply. New data capture technologiesare necessary investments; then, as systems are institutionalizedand standard operating procedures are refined, new technologiesoften result in cost efficiencies, notes Zmud.Zmud has a history as a serial entrepreneur. In 2000, Zmudand Jean Wolf founded GeoStats, a firm focused on technologyapplications in transportation research. Almost 10 years later,NuStats is a partner to Mygistics, a firm creating a detailed, contiguousmodel of the entire United States, Canada, and Mexico,simulating all travelers on the network to accurately predictcurrent and future traffic volumes and travel times. NuStatsbrings a survey research component that will use Mygistics technologyto create the first nationwide transportation panel.Zmud credits her long history of active engagement in TRBactivities for her continued focus on emerging needs for, andsources of, passenger and freight data. Currently, she chairs theData and Information Systems section of the Technical ActivitiesCouncil’s Policy and Organization Group, presiding over 11committees that work to raise awareness about weaknesses orgaps in transportation data and to highlight effective techniquesfor strengthening the nation’s transportation data infrastructure.Before this, Zmud chaired the TRB Travel Survey MethodsCommittee. Outside of the data section, she is an active friendof the travel behavior, road pricing, and public transit committees,and a member of the TRB–National Research CouncilCommittee on Equity Implications of Alternative TransportationFinance Mechanisms, the National Cooperative FreightResearch Program Project Panel for the Truck Idling ScopingStudy, and planning committees for the Innovations in TravelModeling Conference and the Freight Data Research Road Map.Zmud’s other activities include cochair of the InternationalSteering Committee on Travel Survey Conferences, and memberof the Regional Infrastructure and Development Committeeof the Greater Austin Chamber of Commerce.TR NEWS 264 SEPTEMBER–OCTOBER 200931

TRB HIGHLIGHTSSHRP 2 RESEARCH UPDATE—Jim Sayer, University of MichiganTransportation Research Institute (at podium), relates recent newsabout data manipulation and integrity as part of the Fourth SafetyResearch Symposium sponsored by the Second Strategic HighwayResearch Program (SHRP 2) at the Keck Center of the NationalAcademies in Washington, D.C., on Thursday, July 23. Sayer joinedTrent Victor of Volvo, Sweden (seated, facing audience); WuHongbo of China; Fred Wegman of the SWOV Institute for RoadSafety Research, Netherlands; and Tom Dingus of Virginia TechTransportation Institute, at the session to present updates onSHRP 2 international research.CREATIVE TRANSIT TECHNOLOGY—Gordon Drukier of AdvancedFuel Research, Inc. (left), describes the second phase of a projectusing security cameras to detect radioactivity in transit stations toTransit Innovations Deserving Exploratory Analysis (IDEA) programpanel members (from left:) Greg Hull, Michael Taborn, John Walsh,Gregory Cook, Mike Flanigon, and Henry Nejako, on Thursday,August 6, at the Keck Center. The prototype system explored inDrukier’s project would integrate the transit security camerasalready installed in subway stations with newly developed softwarethat could detect radioactive materials nearby.IN MEMORIAMTR NEWS 264 SEPTEMBER–OCTOBER 200932Wayne Shackelford1933–2009GEORGIA DOTWayne Shackelford, 75, formerCommissioner of the GeorgiaDepartment of Transportation (DOT)and past TRB Executive CommitteeChair, died Tuesday, September 1, inSnellville, Georgia. As Georgia DOTCommissioner from 1991 to 2000,Shackelford presided over an era of swiftgrowth and transportation developmentin the state, and supervised such projects as the transportation managementprogram for the 1996 Olympic Games in Atlanta. In 1996,he became a member of the TRB Executive Committee, serving aschair in 1999 and as a member until 2002.Born in Carroll County, Georgia, in 1933, Shackelford graduatedfrom Berry College in Rome, Georgia, and took graduate courses atthe University of Georgia in Athens. He worked as a HaralsonCounty extension agent, and in 1960 began a long career in theGwinnett County administration. After several decades with GwinnettCounty, Shackelford became a real estate developer; his projectsincluded the Town Center Mall in Kennesaw, Georgia, and GwinnettPlace Mall. His vision of growth and establishment of infrastructureset the precedent for the rapid expansion of the Atlantasuburbs in the 1980s and 1990s.In 1991, Governor Zell Miller nominated Shackelford—knownto friends as “Shack”— as Commissioner of the state DOT. DuringShackelford’s 9-year tenure, the state’s population grew by 1.5 millionand the budget for the 3-year list of approved transportationprojects expanded from $2.6 billion to $5.1 billion. He also wasinvolved in the creation of the Transportation Management Centerin Atlanta, and played a vital role in implementing intelligent transportationsystems (ITS) in preparation for the 1996 Olympics.After returning to the private sector in 2000, Shackelford continuedhis work as a community advocate, lobbying for a commuterrail line linking the Atlanta campuses of Emory University andGeorgia Tech—nicknamed the “Brain Train.” In 2007, the new interchangebetween SH-316 and I-85 was named in Shackelford’s honor.From 1995 to 1999, Shackelford served on the TRB StrategicHighway Research Program (SHRP) Committee, which advised theFederal Highway Administration and the American Association ofState Highway and Transportation Officials (AASHTO) on the conductof a national program to implement the results of the firstSHRP. In addition to his service as member and chair of the TRBExecutive Committee, he was also a member of its Subcommitteefor National Research Council Oversight and its Subcommittee onPlanning and Policy Review.Shackelford served as President of AASHTO in 1995 and as presidentof the Southeastern Association of State Highway and TransportationOfficials in 1993. He also chaired the Board of Directorsof the Intelligent Transportation Society of America from 1998 to1999. In 2001, for his outstanding contributions to highwayprogress, Shackelford received the George S. Bartlett Award, awardedjointly by AASHTO, the American Road and TransportationBuilders’ Association, and TRB. Shackelford was a board member ofthe Georgia 4-H Foundation and of the Gwinnett County Fair Association,and a lifetime member of the Gwinnett Historical Society.

NEWS BRIEFSDrivers perceive anincrease in distracteddriving, aggressivedriving, and speeding onthe roadways.Fewer Highway Crashes,But More Danger FeltThe number of fatalities from car crashes last yearwas the fewest since 1961, the AAA Foundation forTraffic Safety reports, but many drivers say they feelless safe on the roads today than they did 5 years ago.According to the 2009 Traffic Safety Culture Index,released in July, drivers stated that distracted drivingwas a serious threat to their safety, but admitted thatthey too engaged in many of the same behaviorswhile driving—sending text messages or e-mails,talking on cell phones, and running red lights.About half of the drivers surveyed said that drivingsafety was about the same as it was 5 years ago;however, only 12 percent reported that they felt saferdriving now, and 35 percent thought they were lesssafe. About one-third of the drivers who reportedfeeling less safe cited distracted driving, along withaggressive driving and speeding, as the reasons.When respondents were asked about perceivedthreats to their safety, the top three threats—rated as“very serious”—were driving after drinking alcohol(90 percent), sending or reading text messages whiledriving (87 percent), and drivers not paying attention(79 percent), according to the report.When asked about their driving behaviors overthe past month, two-thirds of drivers stated that theytalked on a cell phone while driving; 28 percent didso fairly often or regularly. Forty-four percentreported speeding 15 mph over the speed limit onhighways, and 29 percent said they had run a redlight even when it would have been possible to stopsafely. Twenty-one percent of drivers reported textmessaging while driving. Even though 95 percent ofdrivers deemed sending text messages while drivingto be a completely or somewhat unacceptable behavior,nearly 20 percent of these drivers reported havingread or sent a text message or e-mail themselveswhile driving. Similar scenarios were found withother behaviors such as red light running, speeding,tailgating, and talking on a handheld cell phone.To see the report, visit tinyurl.com/AAAFTSreport0709.Alcohol, Drug Useby Drivers DeclinesA survey by the National Highway Traffic SafetyAdministration (NHTSA), released in July, found acontinued decline in the number of drivers impairedby alcohol on weekend nights. NHTSA’s Traffic SafetyFacts Research Note is the latest in a series of roadsidesurveys, conducted over four decades in 300locations nationwide, that have measured weekendnighttime drivers’ blood alcohol levels. The latestsurvey, from 2007, included for the first time dataabout drivers’ use of potentially impairing drugs.Since 1973, when the first of the four surveys wastaken, the percentage of sampled drivers with bloodalcohol content (BAC) over .08 has declined dramatically,from 7.5 percent to 2.2 percent. Althoughthe percentage of underage drivers in fatal crasheswith an illegal BAC increased from 1996 to 2007, the(continued on page 34)CITY OF NORCO, CACheckpoints for driveralcohol use also arereporting data on drivers’use of potentiallyimpairing drugs.TR NEWS 264 SEPTEMBER–OCTOBER 200933

NEWS BRIEFS(continued from page 33)percentage of underage drivers with an illegal BAChas decreased since 1973.Illegal drugs, as well as prescription and over-thecountermedications, were included in NHTSA’s 2007survey findings. According to the report, 16.3 percentof nighttime drivers had positive drug testresults—however, this does not necessarily indicateimpairment. The most commonly detected drugswere marijuana (8.6 percent of drivers), cocaine (3.9percent), and methamphetamine (1.3 percent).Additional research is needed to determine whichdrugs and dosage levels might impair driving.NHTSA is sponsoring a study to examine the linkbetween drug use and involvement in crashes; resultsare expected in 2012.INTERNATIONAL NEWSDetermining Crash Riskfor Older DriversAge is not the sole determining factor of driver capacity,according to a study recently released by VTI, theSwedish National Road and Transport Research Institute.Commissioned by the Norwegian Public RoadsAdministration (Statens Vegvesen) and conductedin collaboration with TØI, Norway’s Institute ofTransport Economics, the report compiled and analyzedpolice-reported accidents in Norway, a literaturestudy, and experimental studies in Norway andSweden to identify hazardous situations for driversage 65 and older and to examine visual behavior inthese situations.The VTI study found that the most frequent typeof accident among older drivers occurs when thedriver is making a left turn and is hit by anothervehicle on the right or left side. Rear-end collisions—the most frequent among all drivers—are less commonfor older drivers, according to the report.Researchers found that older drivers had proportionatelyfewer accidents than younger ones in situationsof inclement weather, poor visibility, orhazardous road conditions; this indicates that olderdrivers tend to avoid driving in these situations.The study also reconsidered the assumption thatadvanced age naturally implies risky driving behavior.According to researchers, driving risk in thesenior age group comes from two main causes—illnessand fatigue. As a group, older people had moreindividual differences in driving capacity thanyounger people; subsequent methods to determinecrash risk or unsuitable drivers must be refinedbeyond age groups, the study concluded.For more information, see www.vti.se/EPi-Browser/Publikationer/R656ASve.pdf.TR NEWS 264 SEPTEMBER–OCTOBER 200934Aviation Group SetsEnvironmental GoalsThe International Air Transport Association (IATA)has set three environment-friendly targets for theaviation industry: by 2020, a 25 percent improvementin fuel efficiency from 2005; a 10 percent useof alternative fuels by 2017; and a 50 percent reductionin aviation emissions by 2050. IATA is developinga fourth target—a “carbon-neutral growth” datebeyond which emissions will not increase, even withpopulation growth.According to IATA Director Giovanni Bisignani,aviation emissions will decline by 8 percent this year;although 6 percent of the drop is attributable to therecession, 2 percent is related to implementation ofIATA’s strategy, which incorporates technology, operations,infrastructure, and positive economic measuresto reduce aviation emissions.For more information, visit www.iata.org.Giovanni Bisignani, Director General and CEO ofIATA, opens the 65th IATA Annual General Meetingand World Air Transport Summit in Kuala Lumpur,Malaysia in June.

Integral and Semi-IntegralBridgesMartin P. Burke, Jr. Wiley–Blackwell,2009. 255 pp.; $139.99; 978-140519-418-1.This book traces the evolution ofdeck-type highway bridges fromthe early 1930s to the present,focusing on subjects of significance to the design andconstruction of integral and semi-integral bridges.Also examined are the uncontrolled growth–pressurephenomenon, the culprit of much bridge damage;the attributes and limitations of integral-typebridges to be considered in the design process; thestructure movement systems approach to highwaybridge design; and some of the problem-solving techniquesused by bridge design engineers. Real-life successstories and challenges—such as a bridgereplacement and rehabilitation project in Ohioinvolving more than 1,800 bridges—provide insight.Appendices to this volume include a critique ofa formerly published and incorrect set of concretepavement recommendations; a glossary to helpnovice engineers; and a collection of data anddescriptions pertaining to the integral and semiintegralbridges shown in photographs throughoutthe book. Author Burke is an emeritus member ofthe TRB General Structures Committee.Fragile Networks: Identifying Vulnerabilities andSynergies in an Uncertain WorldAnna Nagurney and Qiang (Patrick) Qiang. Wiley,2009. 313 pp.; $115; 978-0-470-44496-2.Using a mathematical, multivariate approach, thisbook endeavors to help policy makers, urban planners,and business strategists identify critical infrastructureinvestment needs to bolsterdisaster preparation and mitigation.Computer-based networksystems modeling and analysismethods are applied to vulnerabilitiesin congested urban transportationnetworks, logisticalnetworks, supply chains, theInternet, and other systems.The authors explore many network activities:the behavior of network users, demands forresources, resulting flows, and associated costs.Three sections address network fundamentals, efficiencymeasurement, and vulnerability analysis;applications and extensions; and network integration,mergers and acquisitions, and areas of cooperation.Potential areas for risk reduction anddisaster readiness are identified, along with possiblesynergies that can assist in disaster recovery.BOOKSHELFThe books in thissection are not TRBpublications. To order,contact the publisherlisted.The Beginner’s Guide to Aviation BiofuelsAir Transport Action Group, May 2009. Available at www.enviro.aero/biofuels.To advance the use of biofuels in aircraft, the GenevabasedAir Trans port Action Group (ATAG)has publishedThe Beginner’s Guide to Aviation Biofuels. Unlikebiofuels derived from food crops such as rapeseed andcorn that are often unsuitable for use in aircraft, “second-generation”aviation biofuels are sustainably produced,meet performance and safety standards foraviation fuels, and are derived from nonfood crop sources that can be mass-grownin many geographic regions. Several airlines have successfully tested jet fuels fromalternative sources such as camelina, jatropha, and algae. The pamphlet examines thekey safety and technical criteria in the use of aviation biofuels, outlines the testingprocess currently under way, and looks at technical and sustainability challenges.TRB PUBLICATIONSHuman Performance: Infrastructure, InformationSystems, and SimulationTransportation Research Record 2069Authors study the effects of fog on car-following performance,run-off-the-road crashes involving overcorrection,the decision dilemma zone at a signalizedintersection approach, two-way stop-controlled intersectionson divided highways, left-turn warnings,auditory road safety alerts, wireless communicationand entertainment devices’ effects on driving, warningmessages and variable speed limits, right-turningvehicles and pedestrians approaching from the rightside, traveler information delivery mechanisms, andpretrip public transport information use.2008; 92 pp.; TRB affiliates, $40.50; nonaffiliates, $54.Subscriber category: safety and human performance (IVB).Concrete MaterialsTransportation Research Record 2070Presented are papers on internal curing, impactecho scanning for void detection in posttensionedconcrete, chloride permeability and microstructureof mortars incorporating nanomaterials, autoluminescentsurfaces for concrete pavements, propertiesof concrete containing vitreous calcium aluminosilicatepozzolan, modulus contrast betweennear-surface material and deeper material in concretepavements, the influence of curing conditionson strength development, and strategies for shrinkagemitigation.2008; 67 pp.; TRB affiliates, $37.50; nonaffiliates,$50. Subscriber category: materials and construction(IIIB).TR NEWS 264 SEPTEMBER–OCTOBER 200935

BOOKSHELFTRB PUBLICATIONS (continued)TR NEWS 264 SEPTEMBER–OCTOBER 200936Highway Capacity and Quality of Service 2008Transportation Research Record 2071The 15 papers in this volume encompass subjects suchas multimodal levels of service for urban streets, theimpact of inclement weather on freeway traffic, an estimationof U-turn capacity at unsignalized intersections,delay estimation with oversaturated conditions,left-turn blockage and capacity models at a signalizedintersection, the calibration of roundabout models,performance indicators for two-lane rural highways,unsignalized intersection delay, control-type selectionat isolated intersections, driver behavior and gap acceptanceat roundabouts, and actuated signal-controlledintersection capacity analysis with pedestrians.2008; 130 pp.; TRB affiliates, $45; nonaffiliates, $60.Subscriber category: highway operations, capacity, andtraffic control (IVA).Transit: Marketing; Bus and ParatransitTransportation Research Record 2072Explored in this volume’s 15 papers are transit issues,which include a farecard passenger flow model; modeshift from transit to single-occupancy vehicles on ahigh-occupancy toll lane; an automated bus origin–destination matrix; an in-vehicle interface design forbus collision warning systems; bus rapid transit systemsin Latin America and Asia; the gap between publictransportation vehicles and platforms, which canpose a barrier for the disabled; and the assessment ofschedule qualities in paratransit.2008; 147 pp.; TRB affiliates, $48; nonaffiliates, $64.Subscriber category: public transit (VI).Pedestrians 2008Transportation Research Record 2073Video monitoring of pedestrians at signalized intersections,the characteristics and circumstances of collision-involvedpedestrians, models to measurepedestrian activity at signalized intersections, walkingspeed of older pedestrians, the marked-crosswalkdilemma, detectable warnings for visually impairedpedestrians, Segway rider behavior, and other concernsof pedestrians are studied in this volume.2008; 132 pp.; TRB affiliates, $45; nonaffiliates, $60.Subscriber category: safety and human performance(IVB).School Transportation; Bicycles; Motorcycles andMotor ScootersTransportation Research Record 2074Authors examine institutional impediments to walkingand bicycling to school; determining future schoolsites with land use data; effectiveness of school zoneflashers; an analysis of traffic hazard intensity for urbanbicyclists; child biking for nonschool purposes; bicyclefacility planning; bicycle policy in Davis, California;cycling lessons from Europe; effects of increased sales ofmotor scooters and mopeds; and powered two-wheelerand passenger car free-flow speeds in urban areas.2008; 84 pp.; TRB affiliates, $39; nonaffiliates, $52.Subscriber category: safety and human performance(IVB).Operational Effects of Geometrics and AccessManagement 2008Transportation Research Record 2075Operating speed prediction for horizontal curves onrural four-lane highways; an assessment of curve severityand design consistency; the influence of horizontalalignment on operating speed of two-lane rural roads;the safety performance evaluation of highway intersections;the safety of center two-way left-turn lanes ontwo-lane roads; and the safety impact of access controlstandards on crossroads near interchanges are studiedin this volume.2008; 52 pp.; TRB affiliates, $35.25; nonaffiliates, $47.Subscriber category: highway operations, capacity, andtraffic control (IVA).Travel Demand 2008Transportation Research Record 2076Presented are papers on the impact of route choice seton route choice probabilities, the effects of policy ontravel demand decisions under uncertain conditions,the integration of activity-based modeling and dynamictraffic assignment, a joint modeling analysis of tripchainingbehavior on round-trip commutes, an integratedanalysis of toll lanes and bus priority lanes, thesocial context of activity scheduling, integrated transportationland use models, the influence of transportationaccess and market dynamics on property values, atoll demand model, and other subjects.2008; 215 pp.; TRB affiliates, $52.50; nonaffiliates,$70. Subscriber category: planning and administration(IA).Crosscutting Techniques for Planningand Analysis 2008Transportation Research Record 2077Authors present findings on subjects such as the integrationof land use and transportation planning in theNetherlands, the statewide long-range transportationplan for Montana, best practices for traffic impact studies,public involvement in a proposed transportationproject, the relationship between the built environmentand travel behavior, transit-oriented development

TRB PUBLICATIONS (continued)BOOKSHELFin China, modeling urban growth, transit path building,solutions for the sequential travel forecasting procedureusing feedback, synthesized through-tripmodels for small and medium urban areas, and shiftingmodes of travel to national parks.2008; 181 pp.; TRB affiliates, $51; nonaffiliates, $68.Subscriber category: planning and administration (IA).Highway Safety: Planning; Young Drivers; OlderDrivers; Indian Nations; Roundabouts; Traffic LawEnforcement; and Trucks and BusesTransportation Research Record 2078Safety-conscious planning in midsized metropolitanareas, driver injury severity factors in singlevehicle–deercrashes, detection of road hazards bynovice teen and experienced drivers, the effect of passengerage and gender on fatal crash risks of youngdrivers, actual and perceived behavior of older driverson freeways, spinal rotation during a driving task, ananalysis of mobility policies for the elderly, crash reportingon Indian reservations, physical devices for slowingtraffic in rural communities, automated speed enforcementprograms, the effect of truck lane restrictions onfreeways in mountainous areas, and other topics areexplored in this volume.2008; 142 pp.; TRB affiliates, 45; nonaffiliates, $60.Subscriber category: safety and human performance(IVB).Pricing, Economics, and FinanceTransportation Research Record 2079The 18 papers in this volume include topics such aspay-as-you-drive pricing, mileage-based road usercharges, a vehicle-miles-traveled revenue collectionsystem, a new road financing system for U.S. metropolitanareas, a municipal mobility manager, concessionagreements for providing transportationinfrastructure, public–private partnerships, valuecapturemechanisms, transport project appraisal inIsrael, and making the case for funding using resultsfrom performance measures.2008; 153 pp.; TRB affiliates, $48; nonaffiliates, $64.Subscriber category: planning and administration (IA).The TRR Journal Online website provides electronicaccess to the full text of more than 9,700 peerreviewedpapers that have been published as part ofthe Transportation Research Record: Journal ofthe Transportation Research Board (TRR Journal)series since 1996. The site includes the latest insearch technologies and is updated as new TRR Journalpapers become available. To explore the TRROnline service, visit www.TRB.org/TRROnline.Traffic Signal SystemsTransportation Research Record 2080Authors examine the highway–railway interface for thepreempt trap, the effectiveness of lead–lag phasing onprogression bandwidth, the integration of real-timepedestrian performance measures into traffic signal systems,microsimulation of split-cycle offset optimizationtechnique and coordinated actuated traffic control,piecewise optimum delay estimation for improved signalcontrol, variable maximum green time to improverural traffic signal operations, traffic controller performanceof coordinated actuated signal systems duringtime-of-day transition, robust synchronization of arterialactuated signals, and other topics.2008; 119 pp.; TRB affiliates, $41.25; nonaffiliates,$55. Subscriber category: highway operations, capacity,and traffic control (IVA).Construction 2008Transportation Research Record 2081Construction management, design–build projectdelivery, a construction quality index, streamlinedstrategies for highway rehabilitation, automated realtimethree-dimensional location sensing, highway constructionwarranty specifications, the lives of deficientSuperpave® pavements, dynamic cone penetrationquality for cohesive soil embankment construction, andreconstruction of a damaged steel beam bridge are someof the subjects covered in this volume.2008; 175 pp.; TRB affiliates, $51; nonaffiliates, $68.Subscriber category: materials and construction (IIIB).Updated Test and Design Methods for ThermoplasticDrainage PipeNCHRP Report 631This report contains the findings of research performedto develop a recommended load and resistance factordesign (LRFD) specification for thermoplastic pipe usedin culverts and drainage systems for highway structures.In addition to the recommended LRFD specification,the report features a quality assurance specificationfor manufactured thermoplastic pipe.2009; 282 pp.; TRB affiliates, $54; nonaffiliates, $72.Subscriber categories: bridges, other structures, andhydraulics and hydrology (IIC); soils, geology, and foundations(IIIA); materials and construction (IIIB).An Asset-Management Framework for theInterstate Highway SystemNCHRP Report 632A framework for applying asset management principlesand practices to the management of InterstateHighway System (IHS) investments is outlined in thisTR NEWS 264 SEPTEMBER–OCTOBER 200937

BOOKSHELFTRB PUBLICATIONS (continued)TR NEWS 264 SEPTEMBER–OCTOBER 200938To order TRB titlesdescribed in Bookshelf,visit the TRB onlineBookstore, at www.TRB.org/bookstore/, orcontact the BusinessOffice at 202-334-3213.report. The IHS serves a large portion of the nation’shighway transportation demand; the development ofusable management principles and strategies for thesystem presents a challenge. The report describes thescope of this challenge and presents specific assetmanagement practices that may be adapted for theIHS.2009; 71 pp.; TRB affiliates, $34.50; nonaffiliates,$46. Subscriber category: planning and administration(IA).Impact of Shoulder Width and MedianWidth on SafetyNCHRP Report 633Of interest to transportation professionals responsiblefor geometric design and traffic operations, this reportdetails research performed to quantify the safety andoperational impacts of design element trade-offs andtheir associated risks. Recommended are specificcrash prediction models and accident modificationfactors for shoulder width and median width on ruralfour-lane roads.2009; 37 pp.; TRB affiliates, $28.50; nonaffiliates,$38. Subscriber categories: highway operations, capacity,and traffic control (IVA); safety and human performance(IVB).Guidelines for Guardrail ImplementationNCHRP Report 638Authors provide guidance on selecting the appropriatebarrier performance level for the installation oflongitudinal barriers. The report presents performance-levelselection guidelines, as well as site-specificguidelines, to help identify the guardrail testlevel that should be incorporated and to determinewhen guardrail use is not cost-beneficial. Supplementalprocedures for identifying appropriateguardrail test levels assist in expanding the applicabilityof the selection guidelines.2009; 30 pp.; TRB affiliates, $27; nonaffiliates, $36.Subscriber category: highway and facility design (IIA).Debt Finance Practices for Surface TransportationNCHRP Synthesis 395Presented are basic principles of debt issuance forpublic agencies, with a focus on the current practicesof state agencies that are responsible for surface transportationinvestment. A literature review; a comprehensivesurvey of state departments of transportation;selected interviews; and a study of selected state policies,guidelines, and documentation provide guidanceon the effective use of debt financing techniquesto fund investments in transportation infrastructure.2009; 84 pp.; TRB affiliates, $36.75; nonaffiliates,$49. Subscriber category: planning and administration(IA).Transit, Call Centers, and 511:A Guide for Decision MakersTCRP Report 134This guide explores the operational characteristics of511 systems—which disseminate traveler informationby telephone—and examines how the systemsinteract with transit system call centers. Existing 511systems throughout the country are examined, transitagency experiences with and participation in 511are documented, and guidance is presented to assisttransit agencies and 511 system administrators indetermining a strategy for transit and 511 to worktogether.2009; 89 pp.; TRB affiliates, $38.25; nonaffiliates,$51. Subscriber categories: planning and administration(IA) and public transit (VI).Controlling System Costs: Basic and AdvancedScheduling Manuals and Contemporary Issues inTransit SchedulingTCRP Report 135An update to 1998’s Transit Scheduling: Basic andAdvanced Manuals, this report addresses contemporaryissues in transit scheduling. Authors presentinformation on available scheduling tools and techniquesand their capabilities, and provide guidance totransit agencies on a variety of scheduling issues typicallyfaced in a transit operating environment.2009; 401 pp.; TRB affiliates, $41.25; nonaffiliates,$55. Subscriber category: public transit (VI).Deicing Planning Guidelines and Practices forStormwater Management SystemsACRP Report 14One of the first volumes on deicing operations, thisreport examines a wide array of practices designed toprovide for the practical, cost-effective control ofrunoff from aircraft and airfield deicing and anti-icingoperations. The report offers practical technical guidancefor airports, aircraft operators, consultants,designers, and regulators. This two-part volumeincludes as an addendum all the fact sheets listed inthe report.2009; 180 pp.; TRB affiliates, $48; nonaffiliates, $64.Subscriber categories: energy and environment (IB); aviation(V); and bridges, other structures, and hydraulicsand hydrology (IIC).

LETTERS TO THE EDITOREquity of Rail InvestmentsSandra Rosenbloom’s essay, The Equity Implicationsof Financing the Nation’s Surface Transportation System(TR News, No. 261, March–April 2009, pp. 3–9)speaks to a most current topic. She notes, however,that poor people tend to use buses, while the railmodes serve the wealthy. When rail service is availableto the poor, they use it more than they use buses.National data are misleading, because many smallercities have no rail transit. Typically, 55 percent of busriders may be low income, but only 45 percent of railriders may be low income. Annual per capita railridership may be 890 passenger-miles—as in Washington,D.C.—but bus ridership is only 278 annualpassenger-miles per capita. The poor travel 400annual passenger-miles per capita by rail, but only152 by bus (1).The article also notes that rail transit is morecostly than bus, primarily because of capital investment.This may be true for some systems, but not formost. In 2007, rail transit averaged a cost of 37.6cents per passenger-mile, and bus transit averaged 77cents. In large cities with rail transit, some bus operationscost more than $1 per passenger-mile in 2007(1). Moreover, according to accountants, capitalinvestment is not an expense, but an asset. Thecost—called depreciation—comes when the asset isused.In the national capital area, for example, roughly$11 billion has been invested in the Metrorail system,parts of which are now 33 years old. Depreciation isabout 2.5 percent, equal to $275 million per year or17 cents per passenger-mile. Added to the operatingcost, the full cost is 61 cents per passenger-mile, butbus costs were $1.17 per passenger-mile, plus depreciationof about 16 cents, for a total of $1.33 perpassenger-mile—almost equal to taxi costs (2). Saving72 cents per passenger-mile benefits rich andpoor alike.There is more to consider. The national capitalarea consumes 350 gallons of motor fuel per capita,similar to New York City with its subway and commuterrail systems. The national average is 580 gallonsper capita, similar to large cities with no railtransit (3–5). With petroleum at $2.50 per gallon,that is worth $1 billion a year per city, less $67 millionfor the electricity to run rail (1). That isabsolutely equitable for all citizens—although notpossible without public funding of capital investment.—E. L. TennysonRegistered Professional EngineerEmeritus Member, TRB Commuter RailTransportation CommitteeVienna, VirginiaReferences1. National Transit Database. Federal Transit Administration.www.ntdprogram.com.2. Figures derive from professional experience with Metrorailas consultant to the National Capital TransportationAgency; as Public Works Planning Coordinator for ArlingtonCounty, Virginia; and as Chair, Chief AdministrativeOfficers’ Metro Budget Review Committee.3. World Almanac. www.worldalmanac.com.4. Northern Virginia Transportation Commission. www.thinkoutsidethecar.org.5. U.S. Census Bureau. www.census.gov.Oregon’s Definition of EquitySandra Rosenbloom’s article, The Equity Implicationsof Financing the Nation’s Surface TransportationSystem, is informative and well done. In Oregon,we also consider equity among highway user andvehicle classes, based on the costs attributable tovehicles of differing sizes, weights, and other operatingcharacteristics.The principle of cost responsibility—that paymentsfrom transportation system users should be indirect proportion to the costs they impose on thesystem—has served as the cornerstone of Oregonhighway finance for more than 70 years. Under thisdefinition of equity, the fairness of any highway taxationstructure is measured by how well paymentsfrom each vehicle class match the costs associatedwith the use of the highway system by that class. Typicallyapplied to highways, this principle is equallyrelevant to other transportation modes.Oregon conducts periodic studies to quantify andcompare the responsibilities and revenue contributionsof light vehicles up to 10,000 pounds and heavyvehicles of 10,000 pounds or more. Since 1999, thestate constitution has required that these studies beconducted biennially and that highway user tax ratesbe adjusted, if necessary, to ensure “fairness and proportionality”between the major vehicle classes. Thistradition has served the state well by ensuring thathighway taxes and fees are levied in an equitable andefficient manner. This has provided all highway userswith a common basis to support needed increases intransportation funding.—John MerrissManager, Highway Cost Allocation StudiesOregon Department of TransportationSalem, OregonSandra Rosenbloom replies:As John Merriss notes, Oregon is a recognized leaderin addressing equity issues in highway finance. Butweight differences are not the only way in whichvehicles and drivers can have an unfair impact on thehighway system. Two federal commissions have con-TR NEWS 264 SEPTEMBER–OCTOBER 200939

TR NEWS 264 SEPTEMBER–OCTOBER 200940cluded that fuel excise taxes do not charge drivers fairlyfor the congestion or pollution costs that they imposeon others (1, 2).E. L. Tennyson covers many issues, but the most relevantis the income of rail riders versus bus riders. Thedata on which he bases his analyses, however, are notavailable from the sources he cites—for example, theNational Transit Database (NTD) does not contain ridershipinformation by income.In contrast, working from a compilation of 150 onboardsurveys taken between 2000 and 2005, the AmericanPublic Transportation Association found that morethan 43 percent of riders on roadway transit modeshad incomes under $25,000, and less than 12 percenthad incomes of $75,000 or more. Conversely, less than21 percent of rail riders had incomes under $25,000,and more than 30 percent had annual incomes of morethan $75,000 (3). National Household Travel Surveydata from 2001 show similar modal differences byincome (4).I agree that the focus should be on ridership datafrom systems with both rail and bus services, but thosedata are difficult to obtain. The Los Angeles MetropolitanTransit Authority, however, recently reported thatin 2002 the annual income of an average rail rider was83 percent more than that of its average bus rider (5).Calculating ridership costs only from annual operatingdata makes rail expenditures look far more costeffectivethan they are. For illustration, I combinedNTD capital data with operating data for 2007 to computeridership costs by mode for the 10 largest systems:Baltimore, Boston, Chicago, Houston, LosAngeles, New York City, Philadelphia, San Francisco,Seattle, and Washington, D.C. (6).In six of these systems, an average bus trip was lessexpensive than all forms of rail trips; in Houston, theaverage light rail trip cost 270 percent more than theaverage bus trip ($12.32 versus $3.33). In only four ofthe transit systems was the cost of providing a bus tripmore than that for providing some rail trips: Boston,Los Angeles, New York City, and Seattle—and the differencesoften were small. In Los Angeles, the averagebus trip was $2.55, the average heavy rail trip, $2.41,and the average light rail trip, $9.73. In New York, theaverage bus trip was $2.66 versus $2.20 for heavy rail.(Calculations are available on request.)The figures suggest that a few older rail systemstend to have average costs lower than those for busesbecause rail carries a meaningful share of total ridershipin those cities. That is rarely true of newer systems.Depending on the subsidy per trip by mode—thatis, the gap between costs and fares—poorer riders maysubsidize wealthier riders directly or receive lowerqualityservice because rail services capture a disproportionateshare of the budget. Those issues are at theheart of many lawsuits filed against proposed rail servicesby ethnic and racial groups (7–9).Even were rail investments to reduce congestion,energy consumption, or pollution, serious equity issuesremain. At a minimum, we must question (a) if andwhen providing either rail or bus services offsets anyinequities in highway financing, and (b) if it is equitableto fund rail systems at the expense of the bus serviceson which so many poor people depend.References1. Paying Our Way: New Framework for Transportation Finance.Final Report, National Surface Transportation InfrastructureFinancing Commission, 2009. http:// financecommission.dot.gov/Documents/NSTIF_Commission_Final_Report_Mar09FNL.pdf.2. Transportation for Tomorrow. National Surface TransportationPolicy and Revenue Study Commission, 2007. www.transportationfortomorrow.org/final_report.3. A Profile of Public Transportation Passenger Demographic andTravel Characteristics Reported in On-Board Surveys. AmericanPublic Transportation Association, Washington, D.C., 2007.www.apta.com/resources/statistics/Documents/ transitpassenger_characteristics_text_5_29_2007.pdf.4. Polzin, S. E., and X. Chu. Public Transit in America; Resultsfrom the 2001 National Household Travel Survey. ReportBC137-48, National Center for Transit Research, Center forUrban Transportation Research, University of South Florida,Tampa, 2005. www.nctr.usf.edu/pdf/527-09.pdf.5. Los Angeles County Metropolitan Transportation Authority.Adopted Budget, FY 2009, July 1, 2008–June 30, 2009. www.metro.net/about_us/finance/images/budget_adopted_fy09.pdf, p. 241.6. 2007 Transit Profiles: Top 50 Agencies for the 2007 ReportingYear. National Transit Database, Federal Transit Administration,2008. www.ntdprogram.gov/ntdprogram/pubs/top_profiles/2007/Transit_Profiles_Top50 Agencies.pdf.7. Bullard, R. D., G. Johnson, and A. Torres (Eds.). HighwayRobbery; Transportation Racism and New Routes to Equity.South End Press, Cambridge, Massachusetts, 2003.8. Sanchez, T., M. Brenman, J. Ma, and R. Stolz. Right to Transportation;Moving to Equity. American Planning Association,Chicago, 2008.9. TCRP Legal Research Digest 27: Civil Rights Implications of theAllocation of Funds Between Bus and Rail. TransportationResearch Board of the National Academies, Washington, D.C.,2008. http://onlinepubs.trb.org/onlinepubs/tcrp/tcrp_lrd_27.pdf.

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Transportation Research Board89th Annual MeetingWashington, D.C. • January 10–14, 2010Investing in Our Transportation Future—Bold Ideas to Meet Big ChallengesA robust and efficient transportation system is necessary to meet the economic, environmental, and security challenges ahead, including revampingtransportation finance for the 21st century; attaining zero fatalities in transportation; achieving climate change and energy security targets by2050; enhancing and preserving the nation’s transportation infrastructure; and eliminating congestion as we know it. Through more than 60 sessionsand workshops, the spotlight theme for the TRB 89th Annual Meeting will explore bold ideas to meet these challenges.Plan now to• Network with more than 10,000 transportation professionals;• Take advantage of 3,000-plus presentations in approximately 500 sessions and specialty workshops;• Learn from more than 120 exhibits showcasing a variety of transportation-related products and services;• Explore economic, environmental, and security issues from the perspectives of all transportation modes and a range of stakeholders andsubject-matter experts;• Examine how bold ideas addressing big challenges may affect transportation policy making, planning, design, construction, operations, andmaintenance; and• Discover what federal, state, regional, and local transportation agencies are doing—and can do—to address these issues.Register before November 30, 2009, to take advantage of lower fees. For more information, go to www.TRB.org/AnnualMeeting