SkyTrain can operate 28 trains during rush hour--one train every 90 seconds--with only four people in its control room. Tickets are checked and safety and security maintained by uniformed SkyTrain attendants who roam designated beats.
In Vancouver and elsewhere, frequent service has been credited with drawing far more riders than a comparable conventional light-rail system would attract. This claim is supported by large increases in off-peak, or midday, passengers--people who shop, run errands or visit friends on public transit instead of driving, even though rush-hour traffic has long since dissipated.
More riders mean more income, while fewer drivers mean fewer salaries. That adds up to lower operating costs, an important factor in compensating for the much greater cost of building such systems.
Building costs are higher because such systems must have tracks all to themselves--expensive subways or elevated guideways that do not cross automobile traffic, as the Los Angeles-to-Long Beach Blue Line does. A driverless train also requires more elaborate track signals and computer controls than trains operated by drivers.
"You have cars that are much smarter than the conventional light-rail car, and you pay for that technology," said Ward, president of the company that operates Vancouver's SkyTrain.
In addition, driverless systems must have costly security features--extensive closed-circuit television and sophisticated electronic intrusion detectors--to make sure tracks remain clear of people and such urban detritus as abandoned sofas, wrecked cars and stop signs.
This has been a problem in Vancouver, where 13 people have been killed by driverless trains since the system opened in 1986. Ward said 10 of those victims, including a woman last week, were suicides who would not have been spared by driver-operated trains.
Of the remaining three, one was a teen-ager who had climbed a 24-foot-tall section of SkyTrain track before the system had opened. A test train struck and killed him.
Another was a suspected criminal who tried to evade Royal Canadian Mounted Police officers by hiding on the track. The third was a woman who apparently suffered a seizure in a station, fell between two trains and was crushed before she could set off track-bed sensors that would have stopped traffic.
SkyTrain officials discovered early the vulnerability of driverless trains. In 1985, a vandal uprooted a stop sign and its concrete base and threw them over a 10-foot fence onto a section of track not protected by intrusion detectors. A train smacked into it at 50 m.p.h.
Ward said damage was minor, but the incident is still raising questions about safety--in Los Angeles.
California critics, such as transit activists and Rapid Transit District workers, note that the Green Line will run down the center of Interstate 105, the Century Freeway. They wonder what will happen if the tracks were blocked by wrecked cars, spilled furniture or some other flotsam often seen blowing around the freeways.
"What happens if a load of lumber spills on the track?" asked one skeptical RTD employee. "There's a good chance there is going to be nothing there to tell them not to proceed through at 55 m.p.h."
Ed McSpedon, president of Rail Construction Corp., the LACTC's construction subsidiary, said car-pool lanes will separate the Green Line from truck traffic and concrete barriers will separate trains from car pools. The design was approved by the rail safety branch of the state Public Utilities Commission.
"The PUC requires that we have a tall fence on top of those concrete barriers," McSpedon said. "Years ago, we checked with the California Highway Patrol to see how often trucks and cars break through those barriers. The number was zero."
To warn operators of collisions or climbers, he added, the fence will be equipped with electronic intrusion detectors similar to those used in Vancouver, Atlanta and elsewhere. "Anti-terrorist" fencing will be installed on overpasses to deter people from dropping items onto the tracks, he added.
Still, safety issues--real or imagined--have kept some fully automated systems one step shy of driverless. The Bay Area Rapid Transit District built the world's first automated rapid transit system 20 years ago, a feat applauded and built on by many cities that followed.
But concerns about safety and public acceptance--particularly acute after initial systemwide bugs had trains do such things as roll off the tracks at the end of a line--has led BART to staff trains with people who drive only if computers fail. Their primary job is opening and closing doors.
Of all the driverless train services, the VAL trains in Lille, France, boast the best operating record. Glass screens along platform edges have kept even determined suicides off its tracks; not a single death or major injury has been attributed to the system.