Federal highway safety standard 9 provides guidelines to traffic engineers in their identification and surveillance of accident locations. The state of Michigan developed a comprehensive, computerized system of accident inventory called the Michigan accident location index. This system required the coding and computing of the 192 000 km (120 000 miles) of roadway in the state. The procedure for computerizing the roadway network consisted of three tasks: data coding, data entry, and resolution of edit and cross-reference errors. The use of computer programs to assist in each of these tasks resulted in a methodology that proved to be a fast, accurate, and cost-effective approach.

Recent highway accident statistics indicate that the annual number and rate of traffic accident deaths and injuries have declined significantly since the early 1960s. This, along with the fact that vehicle kilometers of travel have generally increased during the last two decades, gives an indication that positive gains are being made by implementing highway safety improvement programs on the highway system.