The Brief The powerful monsoon storm on Aug. 25 tested a dust detection system installed by the Arizona Department of Transportation. The Arizona Department of Transportation's dust detection system, a pilot program unlike any other in the country, faced one of its first real tests during a powerful monsoon storm on Monday, Aug. 25. The backstory:Installed five years ago, the system is designed to prevent catastrophic crashes during dust storms when visibility can suddenly vanish. "All of these things work together to detect when blowing dust reduces visibility, and then the system will activate variable speed limit signs that will drop the speed limit," Groff said. However, only one collision report indicated blowing sand or dust, and no crashes have been definitively connected to the storm.