Since the terrorist attack of September 11, 2001, getting into the LJ.S. became more difficult, and hence slower for Canadian cars and trucks at border crossings. This resulted in long lineups. One such case occurred on the Ambassador Bridge connecting Windsor to Detroit.5 There were nine U.S. customs booths at the Detroit side of the bridge. Each truck took approximately two minutes to get cleared. During the busy hours, about 300 trucks (i.e., one every 12 seconds) arrived at the booths. Assuming that tire standard deviation of getting cleared is I minute per truck and the standard deviation of inter-arrival durations is 6 seconds, how many more U.S. Customs Booths were needed at the Ambassador Bridge to provide a reasonable average wait time (e.g., less than 10 minutes)?