Vehicle Aggressivity

Aggressivity& IncompatibilityDangers Associated with Sport Utility Vehicles,Light Trucks, and VansFACT or FICTIONthefirmwww.vehiclesafetyfirm.cometoddtracy@vehiclesafetyfirm.com5473 Blair Rd - Dallas, Texas 75231214-324-9000

Introduction“Clearly [vehicle aggressivity] has the attention of the industry. It’stalked about in board meetings. It’s talked about in engineeringmeetings. It’s even talked about in sales and marketing meetings. Ican’t think of any engineers right now that are not interested in orconversant with this issue.”Jerry Hirshberg, President of Nissan NorthAmerica Design Operations.New York Times, May 22, 1998Motor vehicle crashes in the United States killed 41,821 individuals and injured 3,189,000others in six million crashes in 2000. In addition to the terrible personal toll, these crashes makea huge economic impact on our society with an estimated annual cost of $230.6 billion dollars inmedical and lost earnings. Most of these fatalities and catastrophic injury victims wereoccupants in smaller vehicles that were impacted by a sport utility vehicle, light truck or van(LTV's). The question that must be asked is: Why are so many people being killed or maimedfollowing an impact with an LTV? The short answer is due to the aggressivity andincompatibility of LTV's with smaller vehicles.About the Cover:Hidden underneath most LTV’s is a roaringlion in the form of a full frame structure that isheavier, taller and more structurally robustthan a passenger car. LTV’s are the lion ofour roadways because they leave a trail ofblood and devastation. Just like theinnocent gazelle has no chance whenattacked by a lion, smaller cars are preyedupon by LTV’s with catastrophic results.Page 2thefirm

LTV’s Market DominanceIn 1975, LTV's were about 16 percent of the US vehicle population. By 1995, 36 percent of allregistered vehicles in the US were LTV's.Since 1980, when LTV's captured 18 percent of the light vehicle market share, there has been asteady increase in LTV sales. By 1996, LTV's had captured 44 percent of the light vehicle marketshare.Vehicle Type Weight(Pounds)% of vehicleregistrations1975 1995Cars< 2500 13 162500- 28 393500+ 43 9TOTAL 84 64Passenger vans vans0 8Cars and Pass. vans Vans84 72Pickups< 3500 1 53500- 9 54000+ 4 6TOTAL 14 16Utility Vehicles < 3500 0 23500- 1 54000+ 1 5TOTAL 2 12Pickups and & LTVs SUV 16 28Market Share (%)50.045.040.035.030.025.020.015.010.05.001980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996YearU.S. Sales of LTV’s from 1980-1996 expressed asa fraction of light vehicle market share(Automotive News Market Data Book)RankMake/Model1 Ford F-Series Pickup2 Chevy Silverado-C/K Pickup3 Toyota Camry4 Dodge Ram Pickup5 Ford Explorer6 Honda Accord7 Ford Taurus8 Honda Civic9 Dodge Caravan10 Chevrolet Cavalier11 Chevy Trail Blazer12 Ford Ranger Pickup13 Ford Focus14 Jeep Grand Cherokee15 Toyota Corol la16 Chevrolet Impala17 Chevrolet Tahoe18 GMC Sierra Pickup19 Chevrolet Malibu20 Pontiac Grand AmTo demonstrate the market dominanceof LTV’s, 10 out of the 20 best sellingvehicles in the US were LTV’s in 2002Page 3thefirm

Aggressivity, What is It?Vehicle manufacturers have been studying the concept of vehicle aggressivity for decades. In 1972, aRenault engineer introduced the idea of vehicle aggressiveness in an ESV (Experimental Safety Vehicle)paper - "taking account of all of the people in an accident, not just those in one of thevehicles." Hence, the concept of vehicle aggressivity focuses on the bullet or striking vehicle, whereasvehicle crashworthiness focuses solely on the occupants of the struck vehicle.AggressivityFatalities / Injuries Causedby Striking VehicleCrashworthinessMaintain Survival SpaceControl EnergyRestrain & Prevent EjectionPackagingFire PreventionAlso in 1972, Enzo Franchini of Fiat presented several papers at international conferences arguing thatmanufacturers should make certain their vehicles were compatable with each other as well as withroadside features.In 1974, Jerry Kosser of the NHTSA wrote that "we must give attention not only to the safety of theoccupant of our vehicles but also to the safety of the human cargo aboard the vehicle withwhich they collide.”Carl Ragland with the NHTSA (National Highway Traffic Safety Administration) wrote in 1979 that"vehicle aggressivity in frontal collisions has long been considered a safety problem." Thatsame year, the NHTSA concluded in its special study of multi-purpose vans that it planned a 5 yearresearch effort to develop "a non-aggressive, crashworthy full-size car." The NHTSA definedvehicle aggressiveness in 1980 to mean "the characteristics of a particular motor vehicle whichdetermines the design to which injury is inflicted upon the occupants of another vehicle withwhich it collides in a particular crash configuration.”In 1984 Calspan published its “Study of Light Truck Aggressivity” paper and concluded that "lighttrucks are more aggressive, on average, than passenger cars."LTV aggressivity issuch a well-knownphenomenon thatcomic strip artistshave lampoonedthem.Page 4thefirm

What is Vehicle Incompatibility?The compatibility of a vehicle is a combination of its crashworthiness and its aggressivity when involved incrashes with other members of the vehicle fleet. When a vehicle is incompatible, that vehicle does not offeran equal level of protection in vehicle-to-vehicle collisions.As a group, LTV's are heavier, built with more rugged construction and have a higher ground clearance thanpassenger cars. Research has shown that LTV’s will oftentimes override the front structural support of thepassenger vehicle’s front bumper in a frontal impact, the rocker panel/sill in a side impact or the rearbumper in a rear impact.Note: Virtually no displacementof rear bumperAs can be seen, the ride heightof an LTV is much higher thanfor a passenger carThis vehicle struck by a Chevy TahoeIn the early 1970's, the NHTSA ran a series of tests to evaluate vehicle compatibility as it relates to frontalimpact override.Vehicle manufactures like Ford Motor Company also began test programs in the early 1980's to addressvehicle compatibility. Vehicle manufacturers also routinely conduct 30-35 mph override testing.Page 5Once a passenger car's front, side or rear structure iscompromised, principles of crashworthiness are defeated and thelikelihood of fatality or serious injury increase dramatically.of fatality or serious injury increase dramatically.thefirmCrashworthiness DestroyedSurvival space is lostEnergy distrubution is lostEnergy disssipation is lostFuel tanks can ruptureOverride Impacts Destroya Vehicle’s Crashworthiness

Does LTV Vehicle Aggressiveness &Incompatibility Lead to More Harm?Vehicle Architecture Rank (AM)Full-size vans 2.47Full-size pickups 2.31Sports-utility vehicles 1.91Small pickups 1.53Minivans 1.46Large cars 1.15Midsize cars 0.70Compact cars 0.58Subcompact cars 0.45To determine whether LTV aggressivity andincompatibility have an increased potential to harmoccupants of the struck vehicle, the NHTSA derived anaggressivity metric.Aggressivity =Driver Fatalities in Collision PartnerNumber of Crashes of Subject VehicleFull-size vans are most aggressive followed by pickups and sport-utility vehicles. Pickups and SUV’s as agroup are 1.66 times more aggressive than cars and passenger vans. It is obvious that weight is not theonly factor dictating aggressivity. Mid-sized cars and small pickups have about the same weight (3000lbs.), however small pickups are over twice as aggressive as mid-sized cars.Another way to evaluate the role aggressiveness and incompatibility plays in vehicle performance is tostudy fatality rates in real world accidents. Although LTV's only account for one-third of all registeredvehicles, traffic crashes between LTV's and passenger cars now account for the majority of fatalities invehicle-to-vehicle collisions. The following statistics suggest that LTV's and passenger cars areincompatible and that LTV's are more aggressive.Year19801996Car-Car6506 (61%)4013 (38%)LTV-Car3580 (34%)5259 (50%)LTV-LTV510 (5%)1225 (12%)TOTAL1059610497Crash pair Ratio of driver fatalities(Frontal collisions), 1992-96Full-size van Car 1 : 6.0Full-size pickup Car 1 : 5.3Utility vehicle Car 1 : 4.1Minivan Car 1 : 3.3Small Pickup Car 1 : 1.6Crash pairRatio of driver fatalities(Side impacts), 1992-96Car (bullet) Car 1 : 6.0Full-size van (bullet) Car 1 : 23Full-size p'up (bullet) Car 1 : 17Utility vehicle (bullet) Car 1 : 20Minivan (bullet) Car 1 : 16Small pickup (bullet) Car 1 : 11Fatalities500045004000350030002500200015001000LTV-to-LTVLTV-to-CarCar-to-LTVCar-to-CarTo determine whether LTV's are more likely to cause a fatal or seriousinjury due to aggressivity and incompatibility one should also comparedriver fatality rates in vehicles with different weight and architecture.These charts demonstrate that in a frontal impact a driver is about sixtimes more likely to be killed in a car, than if he were in a full size vanthat was his crash partner.In a side impact, the driver of the struck vehicle is more than ten timeslikely to be killed than the driver of a truck that T-boned his vehicle.As is evidenced by the crash statistics, the fatality toll in car-LTV frontaland side crashes is disproportionately shouldered by the drivers ofpassenger cars. This conclusion begs the question - Why is there such adisparity?The short answer is due tovehicle mass, vehiclestiffness and vehiclegeometry.Fatalities600050004000300020001000LTV-to-LTVLTV-to-CarCar-to-LTVCar-to-Car5000Page 61980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996YearDistribution of Side Impact Fatalities(FARS 1980-96)thefirm01980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996YearDistribution of Frontal-Frontal Impact Fatalities(FARS 1980-96)

Vehicle WeightIn 2001, IIHS (Insuarance Institute for Highway Safety) tabulated all deaths where both vehicles were1990-1995 models. IIHS concluded that as the weight of the other car increases, the relative risk ofdying increases. If one car weighs less that 2500 lbs, and the colliding car weighs more than 3500 lbs,you are 3.1 times more likely to die than the person in the heavier car. An occupant in a less than 2500 lbcar is 6.7 times more likely to get killed, if hit in the side by another 2500 lb or less car. If hit by a carweighing 2500-3500 lbs., the risk is 12.4 times greater for fatality. Overall, the risk increase for peoplein the side-struck car to die relative to those in the front-striking car is 6.4 times. The relative risksassociated with the lightest cars is 10.8 times and 3.5 times for the heaviest cars.Aggressivity as a function of vehicle massAggressivity Metric4.54.03.53.02.52.01.51.00.50.0750Subcompact CarsCompact CarsMidsize CarsLarge CarsSUVPickup TrucksMinivansFull-Size Vans1,000 1,250 1,500 1,750 2,000 2,250 2,500 2,750 3,000Vehicle Mass (kg.)Crash Type Car Weight (Pounds) Car Weight (Pounds)All

Vehicle GeometryThe front of a vehicle is designed to yield and crush in a controlled manner (through crumple zones) in afrontal collision to lengthen the duration of the crash and, thereby, allow occupants to "ride down" thecrash. If the vehicle did not crush, it would stop immediately upon impact. The occupants would continueto move forward. Therefore, only their restraint system, rather than both the structure and restraint, wouldabsorb the collision forces. The goal of crumple zones is to allow crushing vehicle components to absorbsome of the collision energy, (ride-down) lessening the effects on occupants and, ideally, keeping theoccupant compartment intact.Passengercars are proneto underridean LTVbecause theLTV's rideheight isconsiderablyhigher thanthat of apassengercar.The crumple zone cannot perform properly, however, when a car strikes a much shorter vehicle or is struckby a much taller vehicle. If the taller vehicle's bumper and other energy-absorbing components are severalinches above the passenger car's bumper or side structure, the car's primary structural elements will not beengaged by the taller vehicle. This phenomenon is known as underride/override.In side-impact collisions, override occurs because thetaller vehicle hits the passenger car high on the doorrather than on the lower sill/rocker panel, which is astronger area more likely to resist crush.In rear impact underride collisions, the heavystructural components of the taller vehicle willstrike the weaker pieces of the passenger car,such as the hood and windshield - componentsthat were not designed to absorb energy orprotect vehicle occupants.A 1970’s SAE article examined override/underride collisions between pick-up trucks and smaller cars. The article foundthat “trucks may easily override the structure of a lower profile vehicle with resultant massivedeformation. If the front structure of the truck were lowered, the mass destruction associated withoverride could be mitigated." Another study from that era concluded that "the structure-overriding tendenciesof larger vehicles in a particular collision were found to greatly influence the severity of exposure to injuryfor occupants of the smaller vehicle." The researchers also concluded that "crush-resistant qualities of thepassenger compartment can be improved by such procedure[s] as standardization of bumper heights andby providing vertically oriented frame crash guards at front and rear ends (within the body sheet metal)and by providing intrusion-resisting structures and designs to the passenger compartment doors and sidepanels."The recommendation almost 30 years ago that bumper heights be standardized is of particular interest. Federalregulations require that the height of bumpers on all passenger cars be within a specified range. (49 C.F.R. §581) Thebenefits of uniformity are obvious, considering the need for the structural components of vehicles to "match" in acollision. Pickups, SUV's, and vans are not defined as passenger cars, however, and are not subject to the sameregulation as passenger cars.Page 8thefirm

Vehicle Geometry (con’td)The chart below shows that SUV's have the highest ride height, with an average rocker panel height - the areadirectly behind the front tires - of 390 millimeters (about 16 inches). The SUV rocker height is almost 200millimeters (8 inches) higher than midsize cars "a geometric incompatibility that would readily permit theSUV to override any side structure in a car and directly strike the car occupant."Sill/Rocker panelA 1986 NHTSA study found that light truck aggressivity in side impacts was dependent on the height of thepickup’s hood. The researchers studied twelve collisions and found that a lower hood profile on the truckwould reduce the probability of serious injury to the occupant of the struck car from 97 percent to 11 percent.A Ford manager commented in a May 1998 New York Times article that "the more we can get the alignmentwith the bumpers and where the crash energies are absorbed, the more it helps the problems withthe large vehicles and the small vehicles.”Ford’s Priya Prasad reported in a 2001 article that geometric incompatability was the dominating factor in thestudied vehicle design characteristics. This conclusion reversed his earlier belief in 1997 that LTV’s posed noincreased danger to motorists.However there are those in the industry that still scoff at vehicle incompatibility. “Even if you’redriving a tank down the road, you could always be hit by a locomotive.” Robert Purcell, GMCPage 9thefirm

Vehicle StiffnessStiffness relates to the amount of force required to deform avehicle. LTV's, with the exception of minivans, are stifferthan passenger cars. Most light trucks and SUV's have stiff,full-frame designs, rather than a soft unibody structure likecars and most minivans.A good example of stiffness incompatibility is that of a FordTaurus passenger car compared to a Ford Ranger light truck.A Ranger must be hit with three times as much force as aTaurus to cause 200 millimeters of deformation. In acollision between the two, the Taurus and its occupants willabsorb a disproportionate amount of the crash energy eventhough the vehicles have equivalent mass and ride heights.A study found that the aggressivity effects of light trucks arepresent even when vehicle weights are equivalent"suggesting the influence of frontal structurestiffness in the light trucks."Some within the automotive manufacturing community claimfrontal stiffness is a product of government test requirements. Iffederal regulations measure vehicle safety in large part by howwell a vehicle performs when crashed into a concrete barrier,adding stiffness to the front end may improve that measure. Asstated in an article by three GM employees:The rigid barrier test, utilized in NHTSA'sMVSS [Motor Vehicle Safety Standard] 208and NCAP [New Car Assessment Program]protocols, creates a significant incentivefor manufacturers to make vehicle frontendinitial stiffness (the front 250 mm) assteep as possible. Initially stiff front endsimprove occupant performance numbers inthe U.S. consumer metric (NCAP) testing.00 100 200 300 400 500 600 700 800Deflection (mm)The NHTSA recently concluded an examinationof 175 LTV’s to answer 2 questions:1. Have LTV’s become stiffer over the14 years that NCAP has existed?2. Do stiffer LTV’s do better in theNCAP tests?NHTSA concluded that LTV's have become less stiff and therefore potentially less aggressive and that the less stiffLTV's have a higher NCAP rating.Less stiff vehicles can provide occupant protection superior to that found in SUV's built on rigid-framerails. The 1999 Mercedes M-Class SUV uses a unibody design and crumple zones designed to absorbcrush energy. Like the new VW Beetle, it has received an IIHS "best pick" rating for performance in 40-mph offset frontal-crash testing, scoring considerably better than the full frame Dodge Durango, theMitsubishi Montero and the unibody Jeep Cherokee.Force (kN)800700600500400300200100Ford Ranger (1755 kg)Ford Taurus (1764 kg)Frontal stiffness: small pickup truck(Ford Ranger) vs. Midsize car (Ford Taurus).Aggressivity as a function of vehicle massLinear Stiffness (kN / m)300025002000150010005000750Subcompact CarsCompact CarsMidsize CarsLarge CarsSUVPickup TrucksMinivansFull-Size Vans1,000 1,250 1,500 1,750 2,000 2,250 2,500 2,750 3,000Vehicle Mass (kg.)Page 10Stiffness incompatibility can be improved, even according to those in the industry. Neil Ressler, Ford's vicepresident for Advanced Vehicle Technology has said "there's a whole series of ways to make thesevehicles softer. It's pointless to be defensive about the issue. It affects all of us.” Mr.Ressler’s comments are particularly salient in light of historical design alternatives used to minimizeaggressivity and promote compatibility.thefirm

Design AlternativesIncompatibility between vehicle types is not a newproblem. The original ESV (Experimental Safety Vehicle)program in the 1970’s included a staged crash pulseintended to achieve a reduction in vehicle aggressiveness,despite requiring frontal barrier crash protection at 50MPH. General Motors' approach was to use a multi-stagefront structure with a very rigid occupant compartmentthat was well balanced. This design was ultimatelypatented by GM.Volkswagen began development of compatibility measures inthe late 1960's when they patented a device intended tomitigate the compatibility deficencies of the Microbus andsimilar VW trucks.Minicars also addressed vehicle compatibility problems inthe mid to late 1970's with its RSV (Research Safety Vehicle).The structural design of the RSV resulted in reduced injurymeasures for test dummies in both the RSV and virtually anyvehicle it collided with, or that collided into the RSV. Theseinjury measure reductions were achieved despiteremarkable performance in 50 mph barrier collisions.Minicar’s RSV success was independently confirmed byDynamic Science and JARI (Japanese Automobile ResearchInstitute).The Mercedes M-Class SUV features a bumper thatis equivalent in height to passenger car bumpers.The ML-320 has the same ground clearance as othersport utility vehicles.The 2003 Ford Expedition has a front bumperwhich is compatible in height with the height ofpassenger car bumpers “so it is friendlier toother vehicles in the event of a crash.”Page 11thefirm

Design Alternatives (con’td)The Ford Excursion, the largest SUV on themarket, has a "blocker beam" located behind andbelow the front bumper to prevent passengercars from riding under it in frontal collisions.A design that is actually being used at this timeis active suspension control that lowers the rideheight of a vehicle as the vehicle acceleratesabove a certain speed.The heavy truck industry has been plagued for decades by rear underride impact crashes. As thevideo clips demonstrate, the lack of rear underride protection is dramatic. Some may rememberthat movie star Jane Mansfield died in an underride impact.When reinforced panels are installed, the vehicle does not completely underride the rear portion ofthe heavy truck. Hence, the occupants of the much smaller vehicle have an increased chance ofsurviving even though the vehicles have substantial structural, weight and geometric differences.The reinforced panel serves as an energy absorbing barrier.Page 12thefirm

Design Alternatives (con’td)Apparently realizing that LTV’s are part of our cultural fabric, vehicle manufacturers and component partmanufacturers alike are trying to devise new ways to make vehicles less aggressive and more compatible.Concept IllustrationTRW and Ford Motor Company have performed work on an airbag system that would deploy fromthe bumper of an LTV to absorb some of the impact.Ford has also considered a sinking grille that would drop when a sensor detects an imminent crash,somewhat like a cowcatcher on a railroad locomotive, to offset the override tendencies on a car.Other designs that have been considered by vehiclemanufactures to overcome aggressivity andincompatibility is the use of honeycomb aluminummounted on a strong support frame. This designwould serve as a friendly barrier. This design iscurrently used by Texas Department ofTransportation.Concept IllustrationAnother design that is being considered byGMC is hydraulic actuators, which during acollision would thrust forward six inches sothat the crash pulse is lengthened. Itshould be noted that this design was firstproposed in 1974 by a NHTSA researcher.In a recent magazine article, the author hinted that vehicles of the future would all have the sameunderbody “skateboard” configuration but with a different replaceable body. This concept makes allvehicles have identical crush zones and bumper heights which equates to perfect compatibility andequal aggressiveness.Page 13thefirm

Aggressivity and Incompatibility LitigationAuthor Keith Bradsher reported in his book High and Mighty that a retired Big Three engineerhad told him that "automakers knew that SUV's might be a problem for other roadusers, but underestimated the scope of the problem and then simply chose not todo research that might produce uncomfortable conclusions." According to theengineer "voices were heard, they just weren't listened to."If vehicle manufacturers did in fact know of potential risks, hazards and dangers of LTVaggressivity and incompatibility, and did nothing to design away, guard against or warn aboutthese known risks, hazards and dangers, manufacturers could be held accountable if theychose profits over safety.Profits should never be more important than human safety. However, LTV's have been a cashcow for the vehicle industry. Ford was making $12,000 profit per Expedition and $15,000profit per Navigator. Ford was making so much money on its SUV (Expedition and Navigatorwithout considering sales of the Explorer) program, that is was paying as much as $8,000 inprofit-sharing to each of its 100,000 UAW workers. In 1996 alone, Ford realized a $2.4billion after tax profit from sales of just the Expedition and Navigator.If marketing and management overlooked LTV design and safety concerns that were pointedout by their own engineers, then vehicle manufacturers will potentially face years oflitigation. For the time-being however, manufacturers seem content with rolling out as manyLTV's as possible to cash in on otherwise dwindling profits. As summed up by former ViceChairman of GMC on why SUV's keep getting larger and larger, Harry Pierce responded "ifpigs are big and popular, I guess we'll make pigs.”HoodClassic Bumper UnderrideThis vehicle struck the sideof a Chevy SuburbanRadiatorBumper LineRadiatorHoodDigitized vehicle (right side)Right QPLeft QPDigitized vehicle (left side)Analyzed crash test videoAnalyzed crash test videoPage 14thefirm

ConclusionBrian O’Neill, the president of IIHS, has succinctly stated what areviewed by many to be the prevailing thought on LTV aggressivity andcompatibility:Automakers should design their cars so occupantsare as safe as possible, without worrying aboutincompatibility among cars in crashes. Theprinciple focus on incompatibility improvementsneeds to be on pickups and utility vehicles.In 2001, 7,252,800 LTV's were sold in the US. Due to the sheer numbersof LTV's on US roads today, there is a safety epidemic due to LTVaggressivity and incompatibility. From Detroit to Munich to Tokyo,vehicle manufacturers should take steps immediately to decrease theaggressivity of LTV's by making them less aggressive and morecompatible with smaller vehicles. If not, thousands of people each yearwill continue to be killed and maimed by this vicious lion that is hiddenunderneath all LTV’s.If you have any questions, comments or suggestions please contact me at thenumber listed below or send an e-mail to:etoddtracy@tracycarboy.comPage 15thefirm