Search Results

Transport policy research seeks to predict and substantially reduce the future transport-related greenhouse gas emissions and fuel consumption to prevent negative climate change impacts and protect the environment. However, making such predictions is made difficult due to the uncertainties associated with the anticipated developments of the technology and fuel situation in road transportation, which determine the total fuel use and emissions of the future light-duty vehicle fleet. These include uncertainties in the performance of future vehicles, fuels' emissions, availability of alternative fuels, demand, as well as market deployment of new technologies and fuels. This paper develops a methodology that quantifies the impact of uncertainty on the U.S. transport-related fuel use and emissions by introducing a stochastic technology and fleet assessment model that takes detailed technological and demand inputs.

A methodology is presented with which aggregate emissions from the in-use automobile population can be calculated for any given calendar year. The data base needed for such a calculation is discussed, and areas in which further research is needed are pointed out. Results of a series of calculations are then presented showing the effect on aggregate emissions of various control strategies. The effects of an inspection/maintenance and retrofit program, different vehicle population growth rates, catalyst deterioration in use, and various schedules of new car emission standards for post-1975 vehicles are presented. It is shown that the rate at which old, higher-polluting vehicles are retired from the in-use vehicle population is the major factor in determining the rate at which aggregate emissions will decrease in the 1970s, with the precise level of post-1975 standards only becoming important in the 1980s.