Synthesis of Crash Cushion Guidance
Kevin Schrum, Daniel Albuquerque, Dean Sicking, Karla Lechtenberg, Ronald Faller, John Reid
Crash cushions have unique properties and vary in shape, length, width, and cost. For this study, crash cushions were grouped together according to their repair costs, and each group was compared to each other in a benefit-cost analysis. Installation costs were obtained from State DOTs, but repair costs were obtained from crash test results provided by each system’s manufacturer. Based on the average repair costs, each system considered in this study was sorted into one of three major categories in order to analyze and evaluate the cost-effectiveness of the grouped crash cushions. The categories were: (1) redirecting with repair costs greater than $1,000 (RGM); (2) redirecting with repair costs less than $1,000 (RLM); and (3) non-redirecting sacrificial (NRS). RGM systems often require higher repair costs than RLM systems after being hit, but RLM systems generally have higher installation costs. NRS systems (e.g., sand barrels) are generally less expensive, often require total replacement after a crash has occurred, and may be impractical at locations with high traffic volumes. This research study was performed to identify the optimal cost-effective crash cushion category and all other cost-effective categories for highway scenarios with different roadway, traffic, and roadside characteristics using the Roadside Safety Analysis Program (RSAP). RGM and RLM systems were the most cost-effective systems for freeways and divided rural arterials, while all three categories competed with the unprotected condition on undivided rural arterials and local roads. When only life cycle costs were considered, the minimum impact frequency to recommend RLM systems was determined. For the costs supplied by States and manufacturers, this minimum impact frequency ranged from 0.41 to 0.66 impacts per year (or 1 accident for every 2.45 to 1.52 years), depending on the applicable functional class.
Highway Safety, Roadside Appurtenances, RSAP, Benefit-Cost Analysis, Crash Cushion, Attenuator, Sacrificial, Low Maintenance, Inertial