GPS and heads-up display technology keep Alaska snowplow drivers on the road, even if they can’t see it.
Alaska’s harsh winter weather — an annual average of 40 feet of snow and winds exceeding 140 mph — makes it difficult to keep roads clear. But when the location is Valdez, home to a vital port and a terminal for the Trans-Alaska Pipeline, transportation officials were determined to keep the highway drivable.
“We needed something to try to keep that road open and available to truck traffic,” said Mike Coffey, chief of statewide maintenance and operations for the Alaska Department of Transportation and Public Facilities (ADOT&PF).
The state implemented a GPS- and radar-based system and outfitted snow-removal vehicles with displays similar to those found in fighter planes — an all-electronic view of the highway and approaching vehicles. Based on technology developed at the University of Minnesota through the U.S. Department of Transportation’s Intelligent Vehicle Initiative, the system originally was created to clear snow from Minnesota roadways.
“The problem was as soon as we put the equipment in snowplows here [in Minnesota], it quit snowing, which is slightly ironic,” said Craig Shankwitz, director of the university’s Intelligent Vehicles Laboratory.
Although the need didn’t prove as great in Minnesota, Alaska has been benefiting from the technology since its first use in the winter of 2002-2003.
The ADOT&PF originally outfitted one snowblower and one snowplow with the high-tech equipment, which works to keep the driver in the highway lane while avoiding other vehicles and obstacles like guardrails. The setup is composed of three technologies:
First is differential GPS, which uses information from ground stations and satellites to pinpoint the vehicle’s location with an accuracy of 3 to 5 centimeters, according to Ocie Adams, a project manager for the ADOT&PF.
Second is collision avoidance technology, which uses radar sensors and information from the vehicle positioning system to search for oncoming vehicles.
Last is the driver interface where all the information comes together; it enables drivers to plow snow from the highway in conditions as bad as zero visibility. Using a heads-up display that lets drivers keep their eyes on the road, the interface shows lines that represent the highway’s center line and fog line (the white line painted on the right side of the road), as well as intersections and guardrails. The center and fog lines change color if the driver passes over them, and the seat vibrates and an audio alert can be used.
The display also depicts oncoming vehicles and the image flashes as they get closer to the snowplow. “It allows us to be on the road and stay ahead of things rather than having the guys speed up when the storm is over,” Coffey said. “They’re still going fairly slowly and cautiously when they’re using this — it doesn’t allow them to go out there and drive 50 miles per hour, but it does allow them to be out on the road driving 20 miles per hour.”
Before deploying the technology, operators would grind their snowplows against the guardrail and use it as a guide to follow the road. But that was costly because it eventually flattened the guardrails, which then needed to be replaced. The ADOT&PF also tested a system in which magnets were put into the road and drivers received a warning if they went over the magnet. But, Adams said, the lack of a visual reference made it difficult for drivers to stay in the lanes.
“They would overcorrect and go back over the other side,” he said. “So it was a continuous battle going up and down the mountain.”
Since the technology was first used in Alaska in 2002, it has been updated for increased accuracy and driver comfort, and more trucks were added to the fleet. The first vehicles that were outfitted allowed operators to clear snow from Thompson Pass, a 2,800-foot-high gap in the mountains northeast of Valdez, which is known as the snowiest place in the state. In 2011, three more vehicles were added to the operation. Now one truck focuses on clearing snow in Valdez and about halfway to Thompson Pass on Richardson Highway, and the other trucks cover the pass and remaining distance between it and Valdez.
The system’s location capabilities were improved in October 2011 with the addition of a differential base station that receives information from U.S. and Russian satellites. “The more satellites giving you the position, the higher the resolution that your fix is and the more constant fix you can get in bad weather,” Adams said. “And that’s when we need it the most, when it’s zero visibility and you can’t see beyond the hood of the vehicle.”
Another big upgrade last year included changes to the heads-up display in the vehicles. In the trucks that were outfitted in the first implementation, the display was 6 to 8 inches in front of the driver’s face and it was surrounded by a metal frame. If the driver hit a bump, he might hit his head on the display, and there were complaints from crew members that the setup made them feel claustrophobic. Adams said the new display is mounted on a swivel arm and increases the comfort for the drivers.
Coffey said other states have contacted him about the technology’s applicability to other types of weather — like fog. “If you have a need that justifies the expense, it’s a fabulous technology,” he said. The initial investment for Alaska was $136,000 for the rollout that included outfitting a snowblower and a snowplow, as well as the design, equipment, fabrication, training and installation. The 2011 upgrades — which included outfitting three snowplows, updating the two existing ones and adding another differential base station to increase accuracy — cost $553,000.
The state’s contract with the University of Minnesota expired Dec. 31, 2011 — but that doesn’t mean their partnership is over. Shankwitz said there has been talk about running a gas pipeline adjacent to the oil pipeline, and if that happens, they would like to incorporate GPS base stations along the length of the gas pipeline to support highway operations.
With the recent upgrades, the department of transportation crew is happy with the system and increased safety on the roads. But it may be Alaska truck drivers who benefit the most. “They’re all ecstatic that we’re able to get out there and keep the highway open,” Adams said. “It costs them thousands of dollars every hour that they’re unable to move loads in some cases.”
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