As of January, 1986, 19 states have approved mandatory safety belt use laws (MUL). Significant controversy has accompanied these legislative activities regarding the safety benefits of MUL versus the imposition of governmental regulation on personal choice. The purpose of this paper is to present a description of operational experiences of MUL in the U.S. Emphasis is placed on quantitative evidence of the effectiveness of MUL and the potential benefit of such laws in the state of Arizona. It is recognized that the public and its legislative representatives must deal with a wide range of issues associated with MUL. However, operational experiences should be considered heavily in the decision-making process. MULs have been effective in increasing safety belt use. However, without enforcement and public education, declining use rates can be expected. Preliminary estimates indicate that significant reductions in fatalities and serious injuries can be attributed to seat belt laws.