PRELIMINARY ON-ROAD MEASUREMENT OF THE EFFECT OF OXYGENATED FUEL ON CO EMISSIONS NEAR LAS-VEGAS, NEVADA

A preliminary measurement of an oxygenated fuel effect for in-use vehi cles travelling at freeway speed was conducted near Las Vegas, NV, in January 1991 and May 1992. The experimental design was based on two pr incipal factors: (I) the large volume of traffic that visits Las Vegas from Southern California on three-day holiday weekends and (2) the fa ct that, at the time of the study, the Las Vegas area used oxygenated fuels in the winter and Southern California did not. Measurements were conducted at carefully selected sites 20 km southwest of Las Vegas ne ar Sloan, NV, and were accomplished with the Fuel Efficiency Automobli e Test (FEAT) remote sensor developed at the University of Denver. The January 1991 measurements were made during the Las Vegas oxyfuel seas on, while the May 1992 control measurements were made outside the oxyf uel season. Over 24,500 individual CO concentrations were measured; re gistration data from over 5,500 of these vehicles were obtained from t he license plate numbers. After corrections for differences in velocit y and mean age, the Las Vegas outbound (oxyfuel) CO emissions on Monda y morning of the January holiday weekend showed a difference of -18% /- 11% compared to the inbound (non-oxyfuel) CO emissions on Friday ev ening preceding the holiday weekend.