The objective of this study was to report the results of the continued monitoring of the performance of guardrail end treatments in traffic accidents. This report includes an analysis of accidents involving the breakaway-cable-terminal (BCT), Kentucky's version of the median BCT (MBCT), Kentucky's weakened turned down (Type 7), the Crash Cushion Attenuating Terminal (CAT), and the Breakmaster System. The report includes data for 349 accidents. This includes 232 accidents involving a BCT, 66 accidents involving a MBCT, 37 accidents involving the Type 7 turned-down end treatment, 12 accidents involving the CAT, and 2 accidents involving the Breakmaster.
Considering all accidents, the BCT performed properly in 76 percent of the accidents. A more detailed analysis showed the importance of installing the BCT using the parabolic flare. Use of the BCT end treatment should be continued where geometries permit. While the MBCT performed properly in 64 percent of all accidents, proper performance was 39 percent when only severe impacts were considered. Use of the MBCT should be eliminated or the MBCT modified due to the problems associated with impacts at shallow angles.
Performance of the Type 7 weakened turned-down end treatment was judged to be proper in 84 percent of the accidents involving this type. Performance appears to justify expanded use. The rollover problem experienced with the original "stiff" turned-down design has been significantly reduced.
Performance was judged to proper in 9 of the 12 accidents involving the CAT. Considering the results of CAT impacts in Kentucky, along with those in other states, permits the conclusion to be drawn that the CAT could be classified as operational. The Breakmaster system may provide an alternative to the CAT; however, additional accident data area needed to evaluate the performance of this system.
Digital Object Identifier
Agent, Kenneth R. and Pigman, Jerry G., "Performance of Guardrail End Treatments in Traffic Accidents" (1991). Kentucky Transportation Center Research Report. 678.