For any of you who get nauseated as your bus driver lurches crazily from lane to lane in rush hour traffic, UC Berkeley researchers have tested a bus that steers itself, and it actually works.
The self-steering bus developed by California Partners for Advanced Transit and Highways follows magnetic strips embedded in the road, although drivers still handle acceleration and braking and can take full control of the bus at any time. The technology could make life better for passengers by increasing efficiency, and could cut the cost of rapid transit systems.
"The magnetic guidance system developed at UC Berkeley can both improve safety and provide a smoother ride for our passengers," says Chris
Peeples, president of the board of directors for the Bay Area transit agency AC Transit. "The system has the potential to make bus rapid-transit routes – particularly those that involve bus-only lanes – as efficient as light rail lines, which in turn will make buses more efficient in getting people out of their cars."
The test used a 60-foot research bus traveling along a one-mile stretch of East 14th Street in San Leandro, near San Francisco. During the demo, the coach traveled in a perfectly straight line before pulling into a bus stop and stopping one centimeter from the curb.
Magnetic guidance technology uses magnetic markers embedded every 1.2 meters (4 feet) down the center of the lane and onboard sensors to track them. Alternating the polarity of the magnets creates a code that a computer aboard the bus reads to determine the buses' latitudinal and longitudinal position. A bus doing 60 mph can process data from 88 feet of roadway in less than one second, and the system is robust enough to withstand real-world abuse, says Wei-Bin Zhang, who leads the project. "Today's demonstration marks a significant step in taking the technology off the test track ... towards deployment onto real city streets," he says.
PATH researchers have been experimenting with magnetic guidance systems for about 20 years and have used them to guide passenger cars and industrial equipment like snowplows, but this is the first time they've applied the technology to buses on public roads. "The rising cost of fuel has created greater interest in public transit," says Larry Orcutt, head of research and innovation for Caltrans, the state's transportation agency. "This technology could convince more people to get out of their cars and onto buses and, as a result, reduce congestion."
Magnetic guidance has big potential passenger benefits. The precision demonstrated by the recent test would shave seconds off the time needed to load and unload passengers at a bus, allowing buses to run routes with greater reliability and punctuality. Precise control also could allow bus lanes to be narrowed from 12 feet (the current standard) to 10.
The technology's also relatively cheap. A bus rapid transit system proposed by AC Transit would cost about $273 million, but adding magnetic guidance technology to make it behave more like light rail adds only $5 million. The Valley Transportation Agency, which serves the region around San Jose, California, also has taken a look at the system and determined it would cost $128 million compared to $393 million for light rail.
Photos by Bill Stone, California PATH / UC Berkeley.
How the system works:
The magnets, shown here in a core sample, are embedded in the road every 1.2 meters:
The researchers say the self-steering bus can consistently get this close to the curb:
The bus steers itself, but the driver retains control over acceleration and braking – although the researchers have tested a fully automated bus on a test track with good results:
Video of the test:
https://www.youtube.com/watch?v=MWDL1WxudIE
