A comparative life-cycle energy and emissions analysis for intercity passenger transportation in the U.S. by aviation, intercity bus, and automobile. (October 2016)

• Record Type: Journal Article
• Authors: Liu, Haobing; Xu, Yanzhi "Ann"; Stockwell, Nicholas; Rodgers, Michael O.; Guensler, Randall
• Is Part Of: Transportation research. Volume 48(2016)
• Page Start: 267
• Page End: 283
• Publication Date: 2016-10
• Subjects: Transportation energy analysis -- Life-cycle assessment -- Intercity travel -- Long-distance travel -- Fuel consumption -- Greenhouse gas emissions -- Air pollutants; Transportation -- Research -- Periodicals; Transportation -- Environmental aspects -- Periodicals; 354.76
• DOI: 10.1016/j.trd.2016.08.027
• Languages: English
• ISSNs: 1361-9209

Abstract

Highlights: Energy and emission from vehicle manufacturing and infrastructure cannot be ignored. Each mode can operate efficiently with low emissions in different distance ranges. Compared to air and automobile, intercity bus is the most fuel efficient mode. Air is less fuel efficient than ground modes in short trips for airport activities. High fuel efficiency at air cruise period makes it more efficient for long trips. Abstract: Intercity passenger trips constitute a significant source of energy consumption, greenhouse gas emissions, and criteria pollutant emissions. The most commonly used city-to-city modes in the United States include aircraft, intercity bus, and automobile. This study applies state-of-the-practice models to assess life-cycle fuel consumption and pollutant emissions for intercity trips via aircraft, intercity bus, and automobile. The analyses compare the fuel and emissions impacts of different travel mode scenarios for intercity trips ranging from 200 to 1600 km. Because these modes operate differently with respect to engine technology, fuel type, and vehicle capacity, the modeling techniques and modeling boundaries vary significantly across modes. For aviation systems, much of the energy and emissions are associated with auxiliary equipment activities, infrastructure power supply, and terminal activities, in addition to the vehicle operations between origin/destination. Furthermore, one should not ignore the embodied energy and initial emissions from the manufacturing of the vehicles, and the construction of airports, bus stations, highways and parking lots. Passenger loading factors and travel distances also significantly influence fuel and emissions results on a per-traveler basis. The results show intercity bus is generally the most fuel-efficient mode and produced the lowest per-passenger-trip emissions for the entire range of trip distances examined. Aviation is not a fuel-efficient mode for short trips (<500 km), primarily due to the large energy impacts associated with takeoff and landing, and to some extent from the emissions of ground support equipment associated with any trip distance. However, aviation is more energy efficient and produces less emissions per-passenger-trip than low-occupancy automobiles for trip distances longer than 700–800 km. This study will help inform policy makers and transportation system operators about how differently each intercity system perform across all activities, and provides a basis for future policies designed to encourage mode shifts by range of service. The estimation procedures used in this study can serve as a reference for future analyses of transportation scenarios.