Texas DOT Vehicle Fleet Warning Light Policy Research

This paper presents an overview and preliminary results of current research being conducted by the Texas Transportation Institute (TTI) and the Texas Department of Transportation (TxDOT) to improve the Department’s vehicle fleet warning light policy and procedures. Although the need for vehicle warning lights is well understood and mandated by law, the large number of design options available (types of lights, lens colors, mounting positions, and combinations thereof) to transportation agencies such as TxDOT make establishment and maintenance of a consistent policy regarding vehicle warning lights difficult. Also, there is considerable pressure to incorporate more and more lighting technologies onto maintenance and service vehicles that are similar visually to those implemented on police and other emergency vehicles (i.e., light bars, blue flasher, etc.).  Research conducted by TTI and TxDOT and presented in this paper includes the results of a national survey of vehicle warning light policies by state DOTs, review of human factors and driver behavior research that has influenced warning light policies over the years, and studies of motorist comprehension and driving responses to different warning light configurations.