A study was conducted to assess the effect of shoulder and road widening on accident rates. Twenty-five projects covering 152 mi of road were selected for analysis. Sampled roads had been widened to one of four widths: 32, 36, 40, or 44 ft. Accident rates were compared before and after the construction period. Reductions of 38 to 53% were observed in accident rates, although the amount of reduction varied with traffic volume and the roadway width after construction. Accident rate reduction for the sampled projects was statistically significant at the 95% confidence level for before and after comparisons on most of the roads. Further research of the effects of resurfacing, restoration, and rehabilitation projects on accident rates in New Mexico is recommended.
Abstract