The justification of safety improvements for low volume rural roads has been difficult. Roadblocks of a primarily economic nature have prevented the improvement of many features associated with this type of road, features which have been known to have adverse safety implications for many years. In this report traditional methods of developing a safety index for these roads have been explored and found suitable. The methods include the correlation of accident rates with specific roadway features and the location of "black spots" where atypical numbers of accidents occur. Neither of these approaches in general are of value on low volume (ADT ¾ 1000) rural roads. The combination of two relatively new concepts for safety improvement is recommended as a result of this combination of two relatively new concepts for safety improvements is recommended as result of this study. They are "process based improvements" and "low cost safety improvements". For example, one "process" is to eliminate all hazardous concrete culvert headwalls in a district. The "low cost" aspect relates to either breaking the headwall off at ground level or building up the soil of the roadside to the level of the headwall top surface. A procedure is presented here to identify those combinations of "processes" and "low cost improvements" that should be given priority in a low volume roadway safety improvement program.
Abstract