Characterization of driving patterns and emissions from light-duty vehicles in California. Final report

The project had two primary objectives. The first objective was to develop a computer model capable of characterizing vehicle exhaust emissions over various driving cycles. The second objective was to construct a driving cycle which would be more representative of typical California driving patterns. The contractor accomplished the first task by developing two computer models (VEHSIM and VEHSIME). These models estimate vehicle exhaust emissions based on user supplied speed versus time traces. For the second task, the contractor equipped a chase car with a laser range finder which allowed the chase car to determine the speed of each vehicle being followed. The contractor collected speed-time profile data of hundreds of vehicles along randomly selected road routes in the Greater Metropolitan Los Angeles area in southern California. This was analyzed and used to construct the new driving cycle. When the new driving cycle is compared against the existing Federal Test Procedure (FTP) using the computer models developed by the contractor, emissions of carbon monoxide and oxides of nitrogen are projected to be over twice as high on the new cycle than on the FTP, while the hydrocarbons remained nearly the same over both cycles.