Countermeasures that work : a highway safety countermeasure guide for state highway safety offices. Fourth edition, 2009.

This guide is a basic reference to assist State Highway Safety Offices (SHSOs) in selecting effective, science-based traffic safety countermeasures for major highway safety problem areas. The guide: describes major strategies and countermeasures that are relevant to SHSOs; summarizes their use, effectiveness, costs, and implementation time; and provides references to the most important research summaries and individual studies. The guide is not intended to be a comprehensive list of countermeasures available for State use or a list of expectations for SHSO implementation. For a description of an optimal State countermeasure program, SHSOs should refer to the Highway Safety Program Guidelines, which delineate the principal components of each of the major program areas. (Author/publisher)