Evaluation of Warning Lights on Maintenance of Traffic Devices and Development of Possible Alternatives

This report documents the efforts and results of a number of studies and evaluations performed by TTI researchers to evaluate the effect and value of steady-burn warning lights on temporary traffic control devices used to delineate the correct travel path in work zones.The effort also included a study of steady-burn warning lights on temporary barrier walls relative to the potential use of delineators currently used on permanent barrier wall. The research includes an assessment of the potential incremental increase in luminance (and benefit of that increase to drivers) during vulnerable driving conditions. These conditions include periods of heavy fog, periods when dew has formed on the reflective sheeting on channelizing devices, periods when dirt and grime have accumulated on the channelizing device, and when channelizing devices are viewed by drivers of large trucks who have a larger observation angle between their eye and the vehicle headlights that are illuminating the reflective sheeting. The researchers assessed the effect of warning light misalignment upon its apparent luminance to drivers, as well as the effect of providing steadyburn warning lights on channelizing devices and temporary barrier walls upon driver visual glance behavior, driving behavior, and driver opinions. Finally, the researchers performed an assessment of the costs of providing steady-burn warning lights and the necessary improvements in work zone safety that would need to be achieved in order to offset those costs. Based on the findings, the researchers recommended that the statewide application of steady-burn warning lights in all work zones be discontinued.