Safety Evaluation of Lane and Shoulder Width Combinations on Rural, Two-Lane, Undivided Roads

The goal of this research was to estimate the safety effectiveness of various lane and shoulder width combinations on rural, two-lane, undivided roads in the Evaluation of Low-Cost Safety Improvements Pooled Fund Study (ELCSI-PFS) Phase II. This evaluation intends to identify optimal lane and shoulder width combinations for fixed total paved widths as a countermeasure for roadway departure crashes. The safety effectiveness for lane and shoulder width combinations was determined by conducting a scientifically rigorous case-control evaluation of rural, two-lane, undivided roads in the United States. The ELCSI-PFS provides crash reduction factors and an economic analysis for the targeted safety strategies where possible. This safety improvement and all other targeted strategies in the ELCSI-PFS are identified as low