Energy and Emissions Impacts of Operating Higher-Productivity Vehicles

The American Transportation Research Institute and Cummins, Inc. teamed up to investigate the energy and emissions impacts from operating commercial vehicles at weights equal to or greater than existing federal limits. Six vehicle configurations and four gross vehicle weights (GVWs) were modeled over a representative route to estimate fuel usage and corresponding tailpipe emissions. The results provide a comparative estimate of the potential energy and emission impacts from operating different vehicle configurations at various weights. When six configurations were modeled over a representative route with the Cummins, Inc., vehicle mission simulation model and a simplified algorithm to estimate emissions, fuel consumption and emissions generally decreased for each ton-mile of freight transported when compared with two standard configuration vehicles at 80,000 lb GVW. With the exception of one configuration, decreases in fuel consumption and emissions per ton-mile were 4% to 19% at 100,000 lb GVW, 15% to 22% at 120,000 lb GVW, and 27% at 140,000 lb GVW. The lone exception was for the heaviest vehicle, which experienced an increase in fuel consumption and emissions per ton-mile at a GVW of 100,000 lb when compared with the two standard configurations. At this weight, the added payload weight was insufficient to offset the additional fuel consumption demands of the heavier vehicle. Other than this exception, operating higher-productivity vehicles to accommodate higher GVWs can be expected to decrease fuel consumption and emissions on a ton-mile basis when compared with standard configuration vehicles at 80,000 lb GVW.