Using GPS technology in snowplows
Technology that lets drivers "see" in whiteout conditions is helpful and well worth the cost, said two county engineers who were involved in field tests of the systems—Rich Sanders of Polk County and John Brunkhorst of McLeod County.
The tests were conducted as part of the Intelligent Vehicle Initiative (IVI) Field Operational Test Program, funded by the USDOT through Mn/DOT. Over the course of the multi-year program, researchers at the University's Twin Cities and Duluth campuses developed, tested, and evaluated a variety of vehicle-guidance and collision-avoidance technologies. Four plows, one ambulance, and a State Patrol car took part in operational tests along the Highway 7 corridor in McLeod County. (For more about the IVI, visit www.its.umn.edu/research/ivifieldtest/index.html.)
Technology and equipment used on the McLeod County plow included:
- differential global positioning systems (GPS)
- head-up display (HUD) projected onto a combiner near the windshield
- radar-based collision warning system
- magnetic tape in the road (backup for when GPS signal was lost)
- automatic vehicle location
- haptic (touch) steering wheel feedback
- tactile seat
- numerous cameras for driver reactions
The cost per truck was round $46,000: $14,000 for the truck equipment and about $32,000 for the GPS; labor was extra. Conclusions to date:
- During the test winters there was little heavy snow and thus few poor-visibility events for thorough testing.
- McLeod operators think the HUD is too clumsy and obstructs their view while getting in and out of the cab.
- Operators think the vibrating seat is the best warning system.
- Operators are more comfortable with the latest changes to the equipment and are more trusting of the system than the original set-up.
Overall, the drivers are less skeptical than three years ago and think the system has merit, Brunkhorst said.
Polk County became involved in the program in 2002, Sanders said, and about 25 miles around Crookston have been mapped so that operators can see the centerline, edge strips, mailboxes, and road signs on the HUD. It takes 10 to 15 minutes from when the operator hops in to when the GPS is read, and although the area is flat with few trees, one stretch can lose signals. If five satellites are activated, the accuracy is "pretty close," he said, but if fewer than five are on, the readings could be off by two feet.
Sanders said the system is working really well and is useful in more than whiteout conditions. Even though the area hasn't experienced a blizzard since the installation, operators used the HUD for a 1- to 2-inch snowfall on CS46 to find the centerline at 4:00 a.m. Without the HUD, Sanders explained, "the corridor all looks like one flat surface and in the past, a driver would estimate the line and could have been two to three feet off center, making it difficult to plow."
The LRRB funded the research portion of the project, so the cost to Polk County was $13,000. Polk plans to acquire another system and map another 25 miles, including some trunk highway.
Julie Skallman, director of Mn/DOT State Aid, asked the engineers if the technology is worth the cost. "It is well worth it for me," Sanders replied. "If we can get the bugs worked out, I can see all maintenance plows with it. When the wind blows and causes instant whiteouts, our drivers can't return to the shop, but with this technology they could finish their route and get back to the shop to wait for the wind to ease." Brunkhorst agreed that the system was worthwhile.
Cheri Marti, director of Minnesota LTAP, asked if county boards have been supportive. Brunkhorst said McLeod's board was very supportive and behind the new technology. Sanders agreed, adding, "as costs fall [support] shouldn't be a problem."
For more information contact Brunkhorst at john.brunkhorst@co.mcleod.mn.us or Sanders at rich.sanders@co.polk.mn.us.