Safety Performance Evaluation of Michigan’s Temporary Traffic Control Devices

A wide variety of traffic controlling devices are used in work zones, some of which are not normally found on the roadside or in the traveled way outside of the work zones. These devices are used to enhance the safety of the work zones by controlling the traffic through these areas. Due to the placement of the traffic control devices, the devices themselves may be potentially hazardous to both workers and errant vehicles. The impact performance of many work-zone traffic control devices is mainly unknown and to date limited crash testing has been conducted, under the criteria of National Cooperative Highway Research Program (NCHRP) Report No. 350, Recommended Procedures, for the Safety, Performance Evaluation of Highway Features. The objective of the study was to evaluate the safety performance of existing work-zone traffic control devices through full-scale crash testing. A total of six full-scale crash tests were conducted on various tall-mounted, rigid panel sign supports and Type III barricades with attached warning lights to determine their safety performance according to the Test Level 3 (TL-3) criteria set forth in the NCHRP Report No. 350. Three of the four impacts on the tall-mounted, rigid panel sign supports and one of the two impacts on the Type III barricades resulted in acceptable safety performances. Following the analysis of these crash tests as well as the test results from other testing programs, it has been found that slight variations in design features of the work-zone traffic control devices can lead to very different performance results. Therefore, extreme care should be taken in applying crash test results from one work-zone traffic control device to similar work-zone traffic control devices with slight variations. The results of the crash tests were documented, and conclusions and recommendations pertaining to the safety performance of the existing work-zone traffic control devices were made.