||Development of Safety Performance Functions for Rural Two-Lane Roads in Virginia
Michael D. Fontaine
Associate Director for Safety, Operations, and Traffic Engineering
A safety performance function is a mathematical relationship between the frequency of crashes by severity and causal factors on specific roads. For example, crashes for a given time period can be estimated based on vehicle exposure. For a highway segment, exposure can be measured by the number of vehicles exposed and the distance for which they are exposed.
By comparing actual crashes on a segment of road to that obtained from the safety performance function, the potential for safety improvement can be determined.
The purpose of this study is to develop a set of safety performance functions for various conditions on two-lane highway segments and intersections that can be used to prioritize of the need for safety improvement projects in Virginia.