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 the Arizona Department of Transportation’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.
This month, ADOT engineers are beginning design work to turn that seemingly futuristic vision into reality along a 10-mile stretch of I-10 where dust storms often develop suddenly.
Installation of the state-of-the-art dust-detection system is expected to begin by late next summer between milepost 209 near Eloy and milepost 219 near Picacho Peak, and the system could be in operation by fall 2018 or early 2019.
Sensors placed near the freeway will be able to detect dust as far as a mile or more away. That will give ADOT crews a chance to monitor conditions and alert the public about potentially hazardous situations.
“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.
Once the system is in use and evaluated, similar warning systems could be used in other dust-prone areas, including I-10 in both western and southeastern Arizona, and I-40.
The system, estimated to cost $12.8 million, will be funded in part by a $54 million federal FASTLANE grant ADOT received for I-10 projects that 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.
Along with the threat from monsoon storms in the summer and fall, soil conditions in this area are such that strong wind any time of year can suddenly produce localized dust that severely reduces visibility, a phenomenon known as a dust channel.
ADOT’s plan calls for overhead message boards five miles apart in each direction between mileposts 209 and 219. 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 lower the speed of traffic when dust is present. Closed-circuit cameras placed on poles will allow ADOT staff to confirm the latest conditions and traffic flow.
A key part of designing the system will be evaluating and selecting dust sensors. ADOT’s emphasis will be on accuracy, reliability and durability.
With a goal of making travel on I-10 safer and more efficient, ADOT Director John Halikowski and leaders of transportation departments in California, New Mexico and Texas recently created the I-10 Corridor Coalition. Halikowski said adding this 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.
“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,” Halikowski added.
For additional information on dust storms and safety, including what to do if caught in blowing dust, visit pullasidestayalive.org.