This report documents the results of a study to evaluate the safety and mobility impacts associated with the elimination of steady burn warning lights on drums in construction work zones. National crash data are compared among states with different policies regarding the use of steady burn warning lights and an in-depth investigation of Michigan work zone crashes is also conducted. The results of the crash data investigation are supplemented by a series of field studies that examine driver behaviour in work zones, both with and without steady burn warning lights. Additional field studies are conducted to assess the luminance characteristics of drums with and without lights, as well as the condition of drums in each type of work zone. The luminance studies are supplemented by additional studies that are conducted in a controlled environment. While the presence of steady burn warning lights is found to marginally increase luminance, all luminance measurements were significantly above recommended visibility minimums regardless of whether steady burn lights were in use. Field study results were mixed as steering reversals occurred more frequently, lateral placement was relatively unaffected, and speeds tended to be slightly higher in work zones where steady burn warning lights were present. Purchasing and maintaining steady burn warning lights are found to add significant tangible and intangible costs, which may not deliver sufficient safety benefits to justify such costs. (Author/publisher)
Samenvatting