As snow fell and rush-hour gridlock worsened in metropolitan Minneapolis-St. Paul, bus driver James Geiger couldn't see the road markings beneath the snow and slush -- but he kept rolling right down the shoulder.
Other bus drivers, sensing a harrowing ride down the narrow strip, had pulled back into traffic. But Geiger was piloting a Minnesota Valley Transit Authority (MVTA) bus through a virtual world, projected before his eyes on a drop-down viewfinder.
His bus was equipped with a new navigational system designed at the University of Minnesota. Using a combination of GPS, laser sensors and visual and tactile alerts, the system aims to help drivers navigate shoulders where there is little room for error.
In some places, buses that are 9 1/2 feet wide, including their mirrors, run on shoulders that are 10 1/2 feet wide.
"We're not steering the bus for them," said Michael Abegg, MVTA's planning manager. "... We're going to provide assistance to the drivers, comfort."
With that reassurance, MVTA, the south-metro suburban transit provider, hopes drivers will have the confidence to stick to the shoulders, move quickly and improve reliability.
That will be especially important when the metro area's first bus rapid transit corridor opens next year. The busway is meant to mimic light rail, with buses running on the shoulder between stations instead of trains on a track.
Louis Sanders, director of technical services for the American Public Transportation Association, said transit providers nationwide are using technology to improve bus passenger safety, speed and reliability. In California, another bus guidance system being developed uses magnets embedded in the road.
"There are all kinds of things going on in the bus world," he said, noting that the University of Minnesota is "really one of the leaders in this development process."
Ten buses from the MVTA fleet are testing the Driver Assist System technology, developed in the university's Intelligent Vehicles Laboratory.
When in use, a half-silvered mirror hangs in front of the bus driver's face, allowing the driver to see through to the road with the glowing outline of the shoulder imposed on top.
The system knows the bus location and direction. GPS and a database of the bus route -- in this case, Cedar Avenue -- tracks the bus' position 10 times per second, accurate to within 5 to 8 centimeters.
If the driver strays too far left or right, the stripe on the screen turns from white to red. Then the driver's seat vibrates, like a virtual rumble strip, on the side they are approaching. Finally, resistance on the steering wheel urges the driver to correct the bus position.
MVTA built a simulator, complete with a mockup of a bus cab, to test the technology and train drivers. Some resist the video game-like technology, but drivers with technical aptitude tend to pick it up quickly.
"This is the first application where the general public is on the vehicle," said Craig Shankwitz, director of the university's Intelligent Vehicles Laboratory. "We've been able to address every one of the shortcomings that we had when we first started."
An earlier version of the Driver Assist System, in development since the early 1990s, has been used on snowplows in Alaska and in a smaller pilot on a couple of plows, a State Patrol car and a Metro Transit test bus about 10 years ago.
Bob Gibbons, a spokesman for Metro Transit, said the technology was well received during that test, even in its rudimentary form.
"It wasn't ready for prime time when our part of the research was done," he said, noting that the GPS signal would be lost when the buses passed under bridges. "We're happy to see that it has advanced to the point where it's actually entering service now."
Transit agencies around the country will be paying attention to MVTA's test fleet, including whether it's cost-effective. It cost about $5 million for the simulator, training, technology development and equipment for 10 buses. The funding came through a federal grant to improve Twin Cities transit and relieve congestion.
So far, bus driver Geiger is a fan. "I wasn't 100 percent sold until I had to use it in that snowstorm," he said. "It proved itself."