Paved Highway Shoulders and Accident Experience

Accident rates for rural two-lane highways having paved shoulders are compared with accident rates for similar highways having only grass or otherwise unstabilized shoulders. The significantly lower accident rates on paved shoulder highways are utilized to develop numerical values for the dollar amount of accident cost reduction directly attributable to the presence of a paved shoulder. Treating the dollars of accident cost reduction as benefits, an investment return analysis is performed relating the benefits to paved shoulder construction costs. Paved shoulder construction costs not exceeding $14,000/mile ($8,699/km), both sides, for 3-4 ft (0.9-1.2 m) wide shoulders can be economically justified on the basis of accident cost reductions for two-lane rural primary highways with average daily traffic volumes greater than 2,000 vehicles per day.