Active Warning Systems: Synthesis

Abstract

Active warning systems are traffic control devices consisting of variable signs or flashing beacons with conventional warning signs, which are activated by sensors detecting real-time roadway, environmental, and operational hazards. Currently most active warning systems detect and warn drivers of variable weather or pavement conditions, high-risk vehicle operating speeds, or the presence of intermittent hazards such as other vehicles, pedestrians, or wild animals. Within the Intelligent Transportation Systems framework, active warning systems applications detect these and other variable hazards and communicate these warnings directly to the vehicle or operator. Because most active warning systems are relatively recent, limited long-term system performance data are available. Testing and evaluation of active warning signs should continue to more firmly establish their benefits to highway safety and traffic operations. This paper provides an overview of available active warning systems and discusses their implementation requirements and potential benefits based on results and recommendations from evaluation studies.