Full-scale dynamic tests on guardrails have indicated that guardrail design is seriously lacking in features that would provide safety compatible with modern high-speed traffic. The role of the guardrail design in connection with highway safety is reviewed. Requirements for the simple post bolt and washer are discussed. It is emphasized that the most major responsibility for inspection should be the effect of non-standardization of terminal accessories at bridge abutments and at ends of runs where the rail dips and twists into the ground. The new end shoe design of the Michigan department of highways seems to offer a practical solution. This end shoe can be attached to any standard piece of rail through the conventional eight splice bolts. The shoe transfers the load to the abutment through a minimum of larger bolts. It is recommended that this economic design should be adopted nationally for both downstream and upstream ends of guardrail installations.
Abstract