This month, we have introduced you to weather-responsive management strategies (WRMS) and several of its applications. Dust storms present a significant roadway safety issue due to a sudden and immediate lack of visibility coupled with difficulties in forecasting. Since 2000, dust storms in Arizona have contributed to over 1,200 collisions resulting in 40 fatalities and over 1,100 injuries.
In response to this challenge, the Arizona Department of Transportation (ADOT) looked to do something no other State had done—implement a system that detects and automatically responds to dust events. ADOT selected a section of Interstate 10, in Pinal County, AZ, where 83 dust-related crashes occurred between 2010 and 2015, to deploy the pilot project. The dust detection system includes sensors, dynamic message boards, variable speed limit signs, speed-feedback signs, and closed-circuit cameras (CCTV).
The system detects dust conditions as early as possible and automatically triggers warnings along the corridor and reduces speed in real-time as visibility diminishes. In addition to CCTVs, thirteen spot detection devices are posted along the roadway to detect visibility. When visibility thresholds are hit, the sensors activate a system response. This includes alerting partner agencies to the situation, incrementally lowering the corridor speed using variable speed limit signs along the roadway, and displaying pre-defined warnings on dynamic message signs. Additionally, long-range dust detectors and weather radar are used to detect dust conditions outside the corridor, allowing ADOT to warn drivers about impending conditions as early as possible.