BACKGROUND: Roadway-operations equipment used by transportation agencies for construction, maintenance, incident response, and other similar activities generally operate on all types of roadways, during day and night hours, and under all weather conditions. To improve motorist and work-crew safety, equipment must be readily seen and recognized and, therefore, appropriate colors, retroreflective markings, and warning lights are provided on the equipment to alert motorists of potentially hazardous situations. Combinations of lights of different colors (e.g., amber, blue, and white) and other forms of warning lights (e.g., lighted bars, lighted "arrow sticks," strobe, LED, and alternating flashing), vehicle color, and retroreflective markings are used. However, there is a concern that this variety of color, retroreflective markings, and lighting on roadway-operations equipment and vehicles has evolved without adequate consideration of their effects on the awareness and responsiveness of motorists.
In 2008, NCHRP Project 13-02 developed Guidelines for the Selection and Application of Warning Lights on Roadway Operations Equipment (published as AASHTO Publication Code WL-1 and available as part of NCHRP Report 624). However, because of the significant technology changes and the apparent increased speeds, traffic volumes, and distracted drivers in recent years, there is a need to re-examine the many factors that influence the effectiveness of colors, retroreflective markings, and lighting applied to vehicles and equipment, and develop updated guidelines for use by transportation agency personnel in the procurement process, and thus enhance motorist awareness and safety.
OBJECTIVE: The objective of this research is to develop guidelines, for consideration and adoption by AASHTO, for the selection and application of color, retroreflective markings, and lighting to vehicle and equipment that will effectively identify vehicles and equipment, and communicate their activities to the motoring public, and thus enhance safety. This research is concerned with transportation-agency roadway-operations vehicles and equipment used for construction, maintenance, incident response, and other similar activities.
Phase I: (1) Collect and review relevant literature, specifications and guidelines, research findings, current practices, and other information relative to the selection and application of color, retroreflective markings, and lighting to vehicle and equipment for the purpose of identifying vehicles and equipment, and communicating their activities within the roadway right-of-way to the motoring public. (2) Based on the information gathered in Task 1, identify and discuss the factors influencing the design and selection and application of color, retroreflective markings, and lighting to vehicle and equipment. These factors would include, but not be limited to (1) vehicle and equipment color(s); (2) minimum and maximum lighting configurations (e.g., lighting color(s); flash pattern, flash rate, and light synchronization; light synchronization between multiple vehicles; and light size, type, intensity, quantity, and placement); (3) minimum and maximum conspicuity configurations (retro-reflective marking colors and patterns); (4) ambient lighting; (5) weather conditions; (6) interrelated effects of vehicle color, light color, combination of lighting systems, flash rate, and markings; (7) visibility from all approaches; (8) integration and interaction of warning lights on vehicle-attached or trailered attenuators, arrow boards, arrow panel, and message signs; and (9) visibility effects on adjacent personnel, vehicles, and equipment. Also, identify motorist response and other criteria used in the selection process. (3) Assess the relevance and importance of the factors identified in Task 2 to the selection and application of an effective lighting system, color, and retroreflective markings, and develop a prioritized matrix of these factors. Also, perform gap analysis to identify those factors requiring further research and prepare a prioritized list of those factors recommended for consideration/investigation in Phase II. (4) Prepare an updated, detailed work plan for Phase II that includes investigations for addressing the factors recommended in Task 3 and developing the desired guidelines. (5) Prepare an interim report that documents the research performed in Phase I and includes the updated work plan for Phase II. Following review of the interim report by the panel, the research team will meet with the project panel. Work on Phase II of the project will not begin until the interim report and the Phase II work plan are approved by the NCHRP.
Phase II: (6) Execute the plan approved in Task 5. Based on the results of this work, develop and validate the guidelines for the selection and application of color, retroreflective markings, and lighting to vehicle and equipment for the purpose of identifying vehicles and equipment, and communicating their activities within the roadway right-of-way to the motoring public. The guidelines shall be prepared in a format that will facilitate consideration and adoption by AASHTO, and implementation by highway agencies. The guidelines should include the technical information necessary for developing lighting, marking, and color specifications; means for effectively communicating activity information to the motoring public, and a matrix to prioritize the relevant factors. (7) Submit a final deliverable that documents the entire research effort, and includes the guidelines as a standalone product. The final deliverable shall include an implementation plan for moving the results of this research into practice.
STATUS (February 2021): Project has been initiated. Data collection and analysis currently underway.