The purpose of this study is to measure the costs of the perceived safety threat from triple trailer operation in Oregon. This is done using the political referendum model of a common non-market valuation technique, contingent valuation. Specifically, the average cost of allowing triples will be found so that comparison with previously estimated benefits will provide a measure of net social welfare associated with triple trailer use. The data were collected through in-person interviews conducted in five regions in Oregon. Questions relating to the respondents' attitudes toward triple trailer trucks, driving experience, education and other demographics were asked. The empirical model estimates the probability that respondents will vote to ban triple trailers. The results of this study suggest that there are concerns about the safety of triple trailer operation. However, there seem to be still greater benefits; a result which is consistent with the recent ballot measure. / Graduation date: 1995