2020 brings first-of-its-kind dust detection and warning project

Statewide projects designed to improve Arizonans’ lives

Variable speed limit corridor sign

PHOENIX – A transportation agency cannot stop hazardous dust storms from blowing across highways, but in 2020 the Arizona Department of Transportation pioneered a first-ever in the nation detection and warning system that now provides quick and reliable information to help motorists slow down for safety during storms.

ADOT’s dust detection and warning system on a 10-mile stretch of Interstate 10 near Eloy began operating in June - just in time for the start of the monsoon season - after years of planning an innovative safety project in a desert region where dust storms pose a threat to drivers all year.

One of the innovative approaches project engineers took was to build a system from existing, reliable technologies - then developing a software-intensive application to tie multiple devices into a seamless and automated system.

From a motorists’ perspective, the system is remarkably simple. When sensors see a drop in visibility enough to affect driver safety, variable speed limit signs reduce the posted speed limit from the usual 75 mph to as low as 35 mph. Also, overhead message boards urge drivers to slow down because of reduced visibility.

Behind the scenes, multiple technologies work together: 13 visibility sensors, a weather radar, sensors embedded in the pavement to provide real-time information on the speed and flow of traffic, overhead message boards, speed feedback signs, closed-circuit cameras and overhead message boards. The system operates automatically while being monitored at ADOT’s Traffic Operations Center in Phoenix.

The system was activated six times since June, during an unusually calm monsoon season. Drivers did reduce their speed every time the system was activated, according to information the system gathered during each activation.

The roughly $6.5 million system was funded in part by a federal FASTLANE grant. As a pilot project, the system will advance ADOT’s knowledge of whether similar technologies would be effective along other Arizona highways. The project won a regional award for operations excellence in the 2020 America’s Transportation Awards competition, sponsored by the American Association of State Highway and Transportation Officials, the U.S. Chamber of Commerce and the American Automobile Association.