Traffic safety evaluations: design, implementation, and use
Authors: Frederick M. Streff
Evaluation is a critical, often overlooked component in the development and implementation of traffic safety programs. This is especially true for community traffic safety efforts, which are generally operated with volunteer staffers and small budgets. Effective evaluation of traffic safety programs provides information necessary to help concentrate available resources where they will be most beneficial. Evaluation is also important for the formulation of policy affecting traffic safety. Policy makers require information provided through evaluation for both political and programmatic decision making. It is important to determine policy needs and the political environment surrounding existing or future policies. Such information is invaluable in the political process that surrounds policy formulation. Once policies have been established, evaluations provide information about policy effectiveness. This information is required to determine if policies have accomplished their desired goals and to determine if midcourse adjustments are neccessary for policies to achieve their full potential. Effectiveness evaluations also help to inform policy makers in other regions about the potential for policies to provide desired (or undesired) effects within their own region. Thus, evaluations can help to support the dissemination of useful policies, or halt the spread of harmful or unproductive policies in new regions. In order for evaluations to achieve their maximum potential, they must be designed with the specific needs of the program or policy being evaluated in mind. Rather than try to fully detail evaluation design, implementation, and use, a review of 3 evaluation programs conducted by the UMTRI Injury Analysis and Prevention division is used in this report to illustrate traffic safety evaluations in general. The 3 evaluations focus on (1) behavioral effects of Michigan's compulsory safety belt use law, (2) effects of increasing Michigan's speed limit on rural interstates (and other rural highways built to interstate standards) on crashes and crash injuries, and (3) the biannual telephone survey of public opinions and behaviors regarding traffic safety policy in Michigan.