Crash Testing and Analysis of Work Zone Sign Supports

A wide variety of traffic controlling devices are used in work zones, some of which are not normally found on the roadside nor 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 and analyze the results of full-scale crash testing of flexible panel work zone sign stands to quantify the features that successful devices shared, as well as common features of those devices that failed salient safety criteria. Parameters considered include sign base and upright properties, sign height, cross-member properties and ancillary details. Results of the analysis point to three fundamental design issues that are problematic, these include 1) combinations of base and upright stiffness and strength that generally lead to significant windshield damage, 2) cross-members that lead to windshield damage in the end-on (90 degree) impact orientation, and 3) appurtenances that have an impact on performance. While there are a significant number of variables that control the performance of a given device, these generalizations offer a basis for evaluation of the fundamental design elements.