This report presents the findings of a research project to develop a practical procedures manual for conducting in-service performance evaluations of roadside barriers. The report will be of particular interest to safety practitioners with responsibility for roadside safety improvements. The research team reviewed the literature to identify past and current in-service evaluation studies and determined what methods had been previously effective. An in-service evaluation was planned and performed in portions of the states of Connecticut, Iowa, and North Carolina. The in-service performance of common barriers and terminals was examined by collecting crash, maintenance, and inventory information in the three data collection areas. The information was supplemented with visits to the crash sites to make measurements of the damaged barrier and document the collision scene using photographs. A procedures manual for planning and conducting in-service evaluations of roadside hardware was developed based on the methods used and the lessons learned in the evaluation study. The manual was subsequently used as a guide for an in-service evaluation project performed in Washington State by a different research team and modified based on their experiences and recommendations. (Author/publisher) This report may be accessed by Internet users at http://gulliver.trb.org/publications/nchrp/nchrp_rpt_490.pdf
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