Interactive Forecasting Tool for Impact of New Engine Technologies on Fuel Consumption and Emissions

Recent gasoline price spikes have heightened interest in new technologies to improve vehicle fuel economy. Indeed, policies in the United States and abroad often target new vehicles as a means to improve fuel economy and reduce passenger vehicle emissions. Although fuel economy and emissions performance of new vehicles are easily compared on an individual basis to the extant vehicle stock, information about long-term aggregate effects is much more difficult to obtain. This project addresses this limitation with the development of an interactive tool that allows users to investigate how scenarios of the penetration of new vehicle technologies would affect future fleet fuel consumption and vehicle emissions (CO, HC, NO_x, PM, CO₂). The attractiveness of this approach is in the transparency of the assumptions, the ease with which input variables can be manipulated, and the incorporation of uncertainty. Users can vary a number of parameter inputs (e.g., growth of the passenger vehicle fleet, the rates of technological diffusion, and future emissions and fuel economy of these technologies) and generate instantaneous forecasts of pollution and fuel consumption compared with 2005 levels, as well as a baseline technology scenario, for the period 2005 to 2020. Currently, the tool runs as an Excel spreadsheet application with 15 variable inputs and output for four criteria pollutants, CO₂, and future fuel consumption. This paper describes the motivation for the model, explains its development as a spreadsheet application, and demonstrates its utility with a number of examples. Future work will improve the sophistication of certain default assumptions and upgrade the software from a spreadsheet application to an interactive website.