The Effect of Uncertainty on US Transport-related GHG Emissions and Fuel. Consumption out to 2050

The future of U.S. transport energy requirements and emissions is uncertain. Transport policy research hasexplored a number of scenarios to better understand the future characteristics of U.S. light-duty vehicles.Deterministic scenario analysis is, however, unable to identify the impact of uncertainty on the future U.S.vehicle fleet emissions and energy use. Variables determining the future fleet emissions and fuel use areinherently uncertain and thus the shortfall in understanding the impact of uncertainty on the future of U.S.transport needs to be addressed. This paper uses a probabilistic fleet model to quantify the uncertainties in U.S.vehicle fleet emissions and fuel use for a realistic yet ambitious pathway which results in about a 50%reduction in fleet GHG emissions in 2050. The results show the probability distribution of fleet emissions, fueluse, and energy consumption over time out to 2050. The expected value for the fleet fuel consumption is about450 and 350 billion litres of gasoline equivalent with standard deviations of 40 and 80 in 2030 and 2050,respectively. The expected value for the fleet GHG emissions is about 1,360 and 850 Mt CO2 equivalent withstandard deviation of 130 and 230 in 2030 and 2050 respectively...