Sequential Warning Light System for Work Zone Lane Closures

Research performed to assess the effectiveness of a flashing warning light system for use at work zone lane closures is summarized in this paper. The system is composed of a series of interconnected, synchronized flashing warning lights that produce the illusion of motion. Researchers investigated motorist understanding and perceived usefulness of various designs of the warning light system, and the potential of this system to yield significant operational or safety benefits in actual work zone applications. Results from proving ground and field studies show that the flashing warning light system used in the work zone lane closure is perceived positively and is not confusing to the motoring public. The field study results also revealed that the prototype warning light system may encourage motorists to vacate a closed travel lane farther upstream from the work zone (which is believed to offer a potential safety benefit). When the warning light system was activated at the urban freeway test site (which was a relatively new closure), there was a 23 percent and 63 percent reduction in the number of passenger vehicles and trucks, respectively, in the closed lane 305 m (1000 ft) upstream of the lane closure. However, it should be noted that the system did not significantly effect lane choice at the rural road test site where the lane closure had been installed for six months. Thus, the greatest potential safety benefit of the warning light system may be when it is used in conjunction with short duration or intermediate-term maintenance/construction projects.