The study was designed to gather data from both primary and secondary states regarding investments in informational and educational messages on the use of seat belts. This investment data was correlated to seat belt usage rates. Within secondary states, the coefficient of determination was .99, indicating that most of the variability in usage rate change was due to the investments made in media and educational campaigns. While the coefficient of determination was much lower for primary states (.46 vs .99), the average seat belt usage rate is 11% higher. This suggests that the law itself as well as other variables has more to do with changes in usage rate in primary states. Although Colorado has made impressive improvements, the data points to the possibility that diminishing returns may be close at hand. In the immediate future, it appears that additional investment increments of approximately $35,000 over the current expenditures will yield about a 1% improvement in usage rates. This approximation may be diluted in its impact as rates improve and the State moves closer to the point of diminishing returns. However, continued gains among juvenile seat belt usage hold enough potential to warrant the increases in investment levels. Remaining a secondary state will require increasingly greater investments to maintain an acceptable rate of improvement in seat belt usage. As the marginal utility of each dollar invested drops, more funds will be needed to get the same results of the preceding year. To offset this decline, the Colorado Department of Transportation will need to invest very judiciously and be as knowledgeable as possible regarding the impact of various messages and media.
Abstract