But researchers at UC Berkeley's Richmond field station are experimenting with an electric bus that operates for eight hours without a battery recharge because most of its power is drawn from a "transformer core" placed in the roadway.
Many of the fondest hopes of Caltrans officials and UC researchers are pinned to the "automated highway," which would largely take control of the car out of the hands of the driver and give it to computers.
"When you look at what's going on out there (on the freeways), you can't believe it," Vostrez said. "People are speeding up, slowing down, changing lanes like a bunch of maniacs . . . there's a lot of stress out there. People are even shooting at each other."
Vostrez and Shirley pointed out that only 10% of the available freeway pavement is filled with vehicles at any one time, even in peak traffic periods. But they say capacity could be doubled or even tripled if cars moved at the same speed and if they moved down the center of the freeway lane instead of veering from side to side.
Control of Vehicles
"If we want to occupy less space in a safer manner, we've got to control both the width and the spacing of the vehicles," said Robert E. Parsons, director of the PATH research program.
Cars would be held in the center of the lane by a lateral guidance system that depends on electric sensors placed in the roadbed. When the vehicle veers right or left, the sensors feed that information to an on-board computer, which automatically returns the car to the center of the lane.
Longitudinal control--moving vehicles at high speed without having them crash into each other--was described by one Caltrans engineer as "a smarter version of the 'cruise control' we have on cars now."
In the vehicle Caltrans is testing--designed by John Davis, president of Radar Control Systems of San Diego--this is achieved by radar. The radar scans the terrain ahead 50 to 100 times per second and feeds this information into an on-board computer, which then causes the car to speed up or slow down as necessary to maintain a constant separation between cars.
"What we do is lock onto the car in front," Davis said. "What he does, we do. I truly believe we have a new technology for the automobile industry here, one that will make the freeway system work two or three times better than it does now, and it will be safer, too."
Major Test Scheduled
Davis and his colleagues have been driving the radar-equipped cars for several years but the first major test will come later this year, when a "platoon" of half a dozen vehicles will start using a reversible lane on Interstate 15 north of San Diego during midday hours when the lane is not in use.
Davis said the cost of the radar collision-avoidance system is about $10,000 per unit now but he hopes eventually it can be sold for about $500.
The total cost of the automated highway improvements must be reduced to about $700 per vehicle if they are to be widely used, in Parsons' opinion.
Much of the automated highway technology has been made possible by an "explosion in the sensor field," coupled with the "rapidly declining price of personal computers," Parsons said.
Even so, it will be very expensive to build guideways to control lateral movement and to produce a system that can communicate information to the vehicles and it is not clear where the money will come from.
One possibility is road pricing--that is, charging motorists and other users premium rates to use the automated freeways at peak periods. This has been tried in Hong Kong and in Singapore, with mixed results.
Caltrans Director Best favors road pricing, but the official position is that the agency is merely studying the possibility.
"It's something we're talking about," Earl Shirley said. "It's at the level of consciousness-raising. Politically, it's very controversial."
A major question is this: How will the public react to a system that takes decisions out of the hands of the individual driver and gives them to a computer?
Research into what engineers call human factors is taking place at UC Davis, where one team of faculty members and graduate students is studying how effectively drivers use automated equipment. Another team is investigating how much people might be willing to pay for these systems.
A second problem is what to do with all the new vehicles that a more efficient road system would accommodate. Where will they park? How can gridlock be prevented in downtown commercial districts?
Then there is the question of liability, which Parsons called the Achilles heel of this research effort.
"This system would be much safer than what's out there now," he said, "but with this technology you can trace fault (for accidents). How do you limit liability and keep the 'deep pockets' thing from killing us before we get started?"
Despite these problems and others, most of the researchers are confident that at least some of these new ideas will be adopted, simply because there are no alternatives.