Officials target deadly I-10 dust
Isolated stretch is noted for wrecks
In a single word, Sgt. Lee Bradshaw knows exactly what to expect when the radio in his Highway Patrol car says there has been a crash and a dust storm on Interstate 10. “Mayhem.” And he has a pretty good idea where. Milepost 214, near Picacho. Of the eight dust-related fatal crashes in Arizona in the past five years, half occurred at that marker, where an average of 42,000 vehicles a day pass by.
Bradshaw’s boss, Arizona Department of Public Safety Capt. Brian Preston, has kept a running count of dust-stormrelated crashes since he took command at the regional DPS office in Casa Grande in mid-2011. He has counted 33 crashes in a 40-mile stretch of I-10 in Pinal County. Two-thirds of them occurred within a mile of the small shrine at Milepost 214, placed there after a motorist died in a dust storm in the 1990s.
The problem is well understood, but solutions remain elusive, and vehicles continue to fall prey to the dust, with no sign of a slowdown.
Dust-storm accidents usually involve a combination of heavy traffic, zero visibility, little warning and inattentive drivers. Reducing the carnage from such storms has been an intractable problem. Changing driver behavior takes decades. The state can’t do much about the sources of dust, and many storms are hard to predict. No reliable weather sensors exist near I-10 in Pinal County.
Over the years, Arizona has tried posting warning signs and slowing or metering traffic. The state also has looked at planting windbreaks and has tested roadside sensors. But the crashes keep coming.
In the past two years, the state has redoubled its efforts, prioritizing its public-awareness campaign, increasing patrols during storms, and coordinating with weather forecasters. It has also solicited bids for research and sought ways to spread weather warnings faster.
And still, there was Oct. 29, the day a dust storm killed three people and wrecked 19 vehicles. At Milepost 214. Dust has been involved in 566 crashes, 14 deaths and 394 injuries in Arizona over the past five years, according to state Department of Transportation data.
ADOT first studied dust-related crashes in the 1960s. A half-century later, a series of chainreaction crashes on Oct. 4, 2011, after a series of deadly storms that summer, forced the state to take a concerted look at the deadly combination of dust storms and traffic.
In 2012, ADOT, DPS, the National Weather Service, Pinal County and others decided to hold annual summits to tackle the problem. In March, the NWS pinpointed and mapped the hotspots.
Experts call the problem a matter of the “Three E’s”: education, environment and engineering.
Education
Arizona’s message for motorists is straightforward: If you can’t see into it, don’t drive into it.
ADOT has spent $105,000, more than for any other of its publicservice campaigns, to spread its dust-safety message: “Pull Aside, Stay Alive.”
Drivers are told that if they get caught by a dust storm, to pull as far off the road as possible and turn everything off: all the lights, even hazard flashers. In poor visibility other drivers may try to follow tail lights like they do through fog, and end up rear-ending parked cars waiting out the storm.
The concept isn’t catching on.
“People have short memories,” Bradshaw said. “We have people going 75, 80 mph into zero visibility. It boggles my mind.”
ADOT and DPS officials hope social media changes that. They noticed an uptick in interest during recent storms and credit text and smartphone alerts with helping more drivers make smarter choices.
Kirk Astroth, assistant dean of the College of Life Sciences at the University of Arizona, took it a step further and developed a smartphone app. It takes weather-service alerts, maps them and directs them to a subscriber’s phone, along with the pullaside advisory.
Nearly 7,000 people have signed up, Astroth said.
Environment
A common perception is that dust storms in the desert are unavoidable, that haboobs kick up the biggest traffic problems and that dust is a monsoon-season phenomenon.
Research shows that none of that is true.
Images of a mile-high, 100-mile-wide wall of dust swallowing Phoenix in July 2011 went viral, butthat dust did not cause any freeway accidents.
“That giant haboob that got a lot of national attention didn’t cause us one problem on I-10,” Preston said, explaining that because such storms are so large, they tend to disperse the dust enough that drivers can see through them.
It’s the smaller, local storms, such as the one on Oct. 29, well after the end of the monsoon storm, that give him shivers.
That day, it was sunny and calm at Preston’s office nearby.
“I could drop a candy wrapper and have it land on my feet,” he said. “There was no indication it was coming.”
There was no alert from the National Weather Service. At around 12:30 p.m., a jet of dust blew across the freeway at Milepost 214, obscuring everything.
By the time it cleared, trucks, tankers, recreational vehicles and cars had piled into each other. A dozen people were hurt. Men from Phoenix, Iowa and Washington state were dead. The wreck caused 20 miles of backups and closed the interstate for 12 hours. It was such a mess that investigators are still trying to piece together what precisely happened.
Bradshaw recalls the dangerous conditions during a similar storm: “It’s the middle of the day and it’s dark inside my car. You couldn’t even see your hood.”
The differences between the haboob’s wall of dust and the October storm are vast. The big monsoon-driven storms that occur between June and September can be detected by radar. Once early indications are seen, these storms are fairly easy to predict, meteorologists and air-quality officials say.
But the most deadly dust storms remain near the ground. They are very local. They are hard to
predict; they start and end quickly. And the dust tends to be a lot thicker.
Experts say the frequency and severity of recent dust-storm crashes are not new. They cycle with the climate; in dry years or those with long intervals between rain, the number of storms and crashes goes up. In wet years, they decrease.
Last year, during weather advisories, the DPS began concentrating patrols in a deadly 40-mile corridor of I-10. Officials hoped the patrol officers could serve as roving spotters for forecasters.
For the Oct. 29-type storms, Ken Waters, who coordinates alerts from the Phoenix office of the National Weather Service, has coined the phrase “dust channel” to describe the quick-forming local “rivers” of dust. Mountains funnel the dirt from a low-lying bowl of land, much of which is abandoned farmland, or desert that was dug up for canals and airports.
Undisturbed raw desert doesn’t kick up anywhere near as much dust, experts agree.
Waters said his team relies on radar and local reports similar to those that DPS officers provide to issue timely warnings. There are no radar beacons between urban Phoenix and Tucson, so the radar signal is weakest and most unreliable in the middle — the area of Milepost 214.
Nor are there any weather stations, air-quality monitors or wind sensors along I-10 between the cities, Waters said.
Waters says the state should buy weather sensors for the hotspots. Devices can cost as little as $15 for a basic backyard unit, and range up to $10,000 for a full weather station, he said, adding that a radar system would cost $2 million.
In 2011, ADOT fieldtested an automatic sensor in southeastern Arizona, on I-10 near San Simon. The state spent $600,000 on a prototype, but results were “mixed,” ADOT spokesman Tim Tait said.
The device was inconsistent. It would sometimes flash warnings when dust wasn’t present, and other times fail to warn of dust in the air.
But as hard as these storms are to predict without better equipment, a research team from the University of Arizona may have discov- ered a way.
William Sprigg, an atmospheric-sciences professor, has worked under a grant from NASA for 10 years to pinpoint the sources of dust and predict where airborne particles go.
He takes high-resolution satellite imagery, detailed measurements of soil moisture and cuttingedge atmospheric models to predict to within about 2 miles the origins of dust storms. He can say three days in advance the path it will take, he said.
Sprigg’s Institute for Atmospheric Physics has checked results and found a near-perfect match between what the models show and what happens.
He’s now testing finer resolutions and hopes within a year to get the models accurate to within less than a mile.
“If we ran the model constantly, I could tell you the degree, frequency, location, severity of dust storms across the entire Southwest,” Sprigg said.
His team responded to an ADOT contest in April to deploy the system and use Astroth’s phone app to get the word out, but a competitor won the bid.
“When my team sees an accident that is dustrelated, they are very upset,” he said. “The tool’s available, but it’s not being fully used.”
ADOT hired California-based Sonoma Technology Inc. for $120,000 to gather data about emerging dust events and communicate warnings to the public.
Engineering
Traffic engineers may be powerless to stop dust, but they can design roads and devices to lessen hazards. And they can install signs or message boards to help motorists react better to those hazards.
Waters mapped 12 years of dust-crash data and found that crashes clustered along a 40-mile section of I-10 in Pinal County, between mile markers 190 near Casa Grande and 230 near the Pima County line. Three locations in particular showed accident spikes: Mileposts 214 at Picacho, 192 at McCartney Road in Casa Grande and 225 at Red Rock. All have been the site of deadly crashes.
ADOT has only one set of permanent overheadwarning signs on I-10 in Pinal County, at Milepost 205 near Eloy. ADOT crews occasionally place portable changeable electronic-message boards along the road near Picacho, the agency said.
Robert Samour, who oversees construction and maintenance for ADOT, said the agency is in the early stages of obtaining cameras for the most dangerous stretch of I-10 to monitor conditions and provide advance warning in the same way engineers monitor traffic flow in metro Phoenix.
The DPS next will look at a contract to buy bumper-mounted electronicmessage boards to place on patrol cars. The agency is considering handheld wind-speed readers, said Maj. Larry Scarber, commander of the southern division of the Highway Patrol.
Much of the problem is that dust starts on land away from the ADOT right of way. The state can’t force private landowners to keep down dust.
ADOT has looked at walls, but they become unstable and expensive if they are too tall, and they may not be effective at shorter heights.
Trees could be helpful, but there is no water along I-10 in Pinal County.
In high country, arrays of snow fences line some highways. They work by breaking up the air flow to prevent snow drifting across the road, but, Samour said, he knows of no research testing the fences on dust. In China, a synthetic fabric has been found to work at binding soil on farms.
Any solution will involve funding for maintenance, power and communications. No budget exists.
Sprigg said his lab can test countermeasures in wind tunnels for a fraction of the cost of a demonstration project.
“It is time now for these folks to step up and work with us to see if we can do something about it,” Sprigg said.
ADOT recognizes the need to act.
“This is a problem that will continue unless something dramatic happens,” Tait said.
Bradshaw is not optimistic.
He’s watched as patrol officers have tried to shut down the highway during dust storms, only to endure backlash for disrupting drivers’ schedules.
“It’s hard when you see these storms and there is still all this death and injury,” Bradshaw said.