Annual Report Year 2004 - Civil and Environmental Engineering

Antonio Trani (right), with research scientistNick Hinze (left) and the team inthe Air Transportation Systems laboratorybuilt a model to analyze both technicaland socio-economic factors oftransportation. The model is being usedby NASA to answer questions regardinga personal air taxi system.changed—for SATS services to operate with just one pilot,SATS costs could be reduced to $1.20 per seat/mile, increasingdemand to 3.5 percent of business trips.NASA is also developing technology that would allowhigher volume operations at airports that do not have controltowers or terminal radar and to allow pilots to land safely inlow visibility conditions at minimally equipped airports. Thesedevelopments were shown to significantly improve the safetyand capacity at all uncontrolled airports, and could save millionsof dollars at low-volume towered airports, according toTrani. “However, the technology showed just a moderateincrease in demand for SATS,” he said.Trani’s team is currently using the model to analyze theimpact of incorporating rail and other transportation modes,along with as-yet-unavailable aircraft that have short take-offand landing requirements.“The power of this model is that it can answer questionsand show the impact on many factors in the transportationsystem,” Trani said. “We expect this model will be an importanttool for decision makers. NASA and the FAA can use themodel to determine whether different technologies will makesense and what they need to do to bring those systems intobeing,” he said.RESEARCH NEWSAnalyzing human and technical factorsBy mixing what they call “mathematics,economics,andcommon sense” with decades of experience in transportationsystems, Antonio Trani, along with HojongBaik and a team at the Air Transportation Laboratory havedeveloped a rigorous model that can be used to analyzeboth national and county-level transportation systems.Developed to provide decision support for the small aircrafttransportation system (SATS) [see above], the model isthe first to bundle socio-economic factors, such as demandand pricing, with technical performance specifications.Combining issues like how travelers choose their mode oftravel with specifications of speed, fuel consumption, andeven noise generated can help engineers and planners bettermatch the technology to the need, according to Trani.The model analyzes several layers of overlapping inputs,including the national airspace system, the American travelsurvey, Eurocontrol data, the Woods & Poole EconomicModel, census data, the official airline guide, and vehicle andaircraft cost and performance data. “The model is genetic(self-adapting), so that we can add new datasets and constraints,to help us predict and optimize future technolo-gies,”Trani said. A combination of socioeconomic models anddata sources was used so that predictions can be as accurate aspossible,Trani said.A variety of metrics and constraints can be evaluated,including mobility benefits, such as reduced travel time, economicbenefits, environmental impacts, energy and fuelimpacts and airspace capacity impacts.“Every choice in transportationinvolves a cost/benefit tradeoff,” Trani explained.“Perhaps getting to a destination sooner will cost more dollars,or have a higher environmental impact regarding fuel use ornoise,” he said.Although the model was developed to answer questionsrelated to NASA’s small aircraft effort,Trani’s team is using it toanalyze other transportation modes.“As long as you can tell usthe performance of the vehicle, the routes, and the economicsinvolve, we can accommodate other technologies,”Trani said.In addition to Trani, the modeling team included researchscientists Hojong Baik and Howard Swingle, and graduateresearch assistants S.Ashiabor, N. Hinze, X.Yue,A. Seshadri andK. Murthy.9