AASHTO Journal, 28 October 2016
Engineers at the Arizona Department of Transportation are beginning design work this month to deploy dust-threat warning systems along a 10-mile stretch of Interstate 10 near Picacho where dust storms often develop suddenly.
ADOT said the system could be operating as soon as autumn 2018, and described how the system would work.
“On a stretch of Interstate 10 between Tucson and Phoenix, sensors placed along the highway set off an alert: Dust, whipped up by gusting wind, is creating dangerous driving conditions.
“Immediately, overhead electronic message boards alert drivers to the threat ahead. Programmable signs next to the highway show a speed limit reduced from 75 mph to as slow as 35 mph. Closed-circuit cameras allow staff at [ADOT’s] Traffic Operations Center in Phoenix to see the real-time conditions on the roadway, while in-pavement sensors report the speed and flow of traffic.”
The agency said its engineers are working “to turn that seemingly futuristic vision into reality.”
It expects to begin installations of the hardware by late next summer between milepost 209 near Eloy and milepost 219 near Picacho Peak.
It is also part of a larger, multi-state strategy to make travel on I-10 safer and more efficient. ADOT Director John Halikowski and leaders of transportation agencies in California, New Mexico and Texas recently created the I-10 Corridor Coalition.
Halikowski said adding this dust detection-and-warning system will help achieve the coalition’s goals not only by saving lives but by reducing delays caused by dust-related crashes.
However, he added, “while this detection and warning system will be a great step forward, no amount of technology will replace common sense when it comes to driving in adverse conditions such as blowing dust.”
The system will use sensors near the freeway to detect dust as far as a mile or more away, ADOT said. That will give its crews a chance to monitor conditions and alert the public about potentially hazardous situations.
ADOT’s plan calls for overhead message boards five miles apart in each direction, while variable speed limit signs are to be placed every 1,000 feet for the first mile in each direction and then every two miles, allowing ADOT staff to reduce the traffic speed when dust threatens. Finally, closed-circuit cameras placed on poles will allow ADOT staff to confirm the latest conditions and traffic flow.
“In addition to providing earlier warnings about blowing dust in an especially troublesome area, this innovative system will advance our understanding of whether similar systems can be effective in other locations around Arizona,” said Brent Cain, director of ADOT’s Transportation Systems Management and Operations Division.
ADOT estimated that the system will cost $12.8 million. It will be funded in part by a $54 million federal Fastlane grant that ADOT received for various I-10 projects, which also include widening and improving two of the three stretches between Phoenix and Tucson that aren’t already three lanes in each direction.
Widening those areas and improving interchanges at State Route 87 near Eloy and Jimmie Kerr Boulevard in Casa Grande are scheduled to be completed by winter 2019.