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r <br />30 <br />1. SUMMARY AND CONCLUSIONS <br />In response to the problems of continued air pollution throughout California's urban areas, <br />i some local air pollution control officials have proposed or enacted bans on the use of <br />drive -thru service lanes at locations such as banks and convenience restaurants. <br />Proponents of such a measure argue that drive -thru lanes generate more air pollution than <br />park -and -stop activities. <br />-4 <br />A detailed analysis of the effect of a ban on drive -thru lanes in the'Lake Tahoe region <br />" tt , fs hat.eWonn'Qa g %lt8 rit pah in tit lea- o�ild rgs'r�lt 14 ii deage`� e <br />r ain, o }e _ s of cubpn nonoxid 0• rid s.Mo f. CO emissions for an average trip to <br />a convenience restaurant would decrease by 10% if the ban were eliminated. Emissions of. <br />gases.(Ris?Cs, one of the two main ingredients of smog) would decrease <br />3 by 13% in the summer. and 19% in the winter. Respective decreases of 18% and 15% in <br />summer and winter emissions of oxides ofnitrogen (NOx) would also be realized.. (NOx <br />emissions are the second main ingredient of smog) The results of the analysis for a <br />typical convenience restaurant in the Lake Tahoe region are shown in Figure 1. <br />These results are consistent with a 1991 study of the effect of banning drive -thru service <br />lanes at convenience restaurants in Southern California.'* Previous analyses that have led <br />to other conclusions have suffer om two rinoipal errors. First, none of the earlier <br />i yses looked at the evaporative emissions from cars. These emissions, which consist of <br />gasoline vapors coming from the gas tank and fuel system, ar6 responsible for the majority <br />of the ROO emissions in convenience restadrhtt parking lots, Second, none ofthe earlier <br />analyses used an accurate method for evaluating minute-by- minute emissions of cars in <br />restaurant parldng lots and for a short time after they leave the restaurant. <br />In this analysis, both "hot soak" and "running loss" evaporative emissions were included in <br />the calculations. in addition, existing motor vehicle emissions models were supplemented <br />with a more accurate technique to predict parking lot-arid drive -off emissions ort a minute - <br />by- minute basis. This technique is described in detail in Section 4 of this report <br />In conclusion, there are no emission benefits being realized by the etuient ban on drive- <br />- lint windows ai diher existing or new c6tiveii16nce i estauaants Tn fact, th6rd ill likeeTY id <br />be a slight decrease in emissions of all pollutants if the current ban on drive -tluu windows <br />is eliminated We this analysis is based on Lake Tahoe ambient conditions and data <br />validated for convenience restaurants in this region, the some general conclusions are <br />likely to hold true for shaar restaurants in other locations and under different ambient <br />conditions. It thus appears that efforts in California and other states to prohibit drive -thm <br />windows for air quality purposes are. counterproductive and may result in higher rather <br />than lower emissions. <br />Superscripts denote ret'ereaees provided in Secdon 7. <br />4- <br />