Evaluation of the Michigan TACT Program

Abstract

This report documents the evaluation of the Michigan Ticketing Aggressive Cars and Trucks (TACT) program. The TACT program was conducted in three 2-week waves in the fall of 2013 near Grand Rapids, Michigan. Comparable sites in southeast Michigan served as a comparison area. The TACT program combined high visibility enforcement with a public information and education (PI&E) campaign focused on unsafe driving behaviors of cars and trucks near each other. An evaluation of the TACT implementation found that that the enforcement and PI&E plans were followed reasonably well. Outcomes in terms of driver behaviors, attitudes, and traffic safety were tested by means of surveys of motorists and truck drivers; an observational study of passing and merging behaviors of passenger cars near large trucks; and analysis of crash data. A before/after with comparison design was used to measure any effect in each outcome. Results indicated that the PI&E messages reached the drivers in the program area. Analysis of the survey data did not identify any statistically significant changes in self-reported behaviors among the drivers in the program area. The proportion of safe passing and merging maneuvers recorded in the observational study were quite high before the program and did not change significantly after the program. A Poisson crash rate model adjusted for over-dispersion and using six-years of monthly crash data from the program and comparison areas was developed. It accounted for traffic volumes, proportion of trucks in the traffic, snowfall and precipitation, and the economy. The crash data analysis did not identify significant effects of the program on crash rates.