Occupancy and GHG emissions: thresholds for disruptive transportation modes and emerging technologies

Document Type

Journal Article

Publication Date


Subject Area

place - north america, place - urban, mode - bus, mode - car, planning - environmental impact, technology - alternative fuels, technology - emissions, operations - capacity


Well-to-Wheel GHG Emissions, Dynamic vehicle simulation, Transit bus, Ride-share, Electric bus, Occupancy thresholds


This paper estimates the environmental impact of alternative and conventional transportation technologies across the dimensions of service mode and power source pathway. We simulate the Well-to-Wheel energy consumption and GHG emissions of eight transit buses and passenger car powertrains. Vehicles are simulated under three generalized North American operating contexts (450 operating scenarios) using Autonomie and the GREET database. All technologies are normalized by passenger-service-mode-trip-km-travelled GHG emissions to facilitate equivalent comparison. The results indicate that all simulated mobility solutions carry a large variability; however, the most environmentally competitive solutions are fuel cell electric car-share, battery electric car-share, and battery-electric bus, all powered by low-carbon intensity power sources at average occupancy (0.23–19.7 g CO2e passenger-service-mode-trip-km-travelled-1). Furthermore, transit bus technologies have the potential to reduce up to 2.3 times more GHG per passenger-trip than comparable ride-share technologies. Overall, this paper defines occupancy GHG emission thresholds for mobility solutions to inform environmental decision-making processes.


Permission to publish the abstract has been given by Elsevier, copyright remains with them.


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