TROY, N.Y. -- Picking up doughnuts on the way to work recently, George List slid back into the driver's seat and heard a voice from the cup holder suggest an alternate route.
The car wasn't talking, exactly. The voice came from a hand-held computer nestled in the holder that links his car to 200 other vehicles in the area. Data from all the vehicles -- where they are, how quickly they move -- are being used to create snapshots of area traffic patterns.
The system had detected a bottleneck ahead and quickly calculated a faster route.
''I said, 'Oh, that's interesting; it changed its mind when I was doing something else,' " he said.
List obeyed the machine. He later saw the traffic jam -- at a distance, from another road.
List, director of Rensselaer Polytechnic Institute's Center for Infrastructure and Transportation Studies, co-heads a federally funded project examining a potential high-tech solution to highway congestion. Traffic is tracked through Global Positioning System devices in cars connected wirelessly. Drivers participating in the pilot project essentially act as highway probes, receiving continual feedback from in-car computers intoning commands such as, ''Just ahead, turn right."
''They're benefiting from each other being eyes and ears in the network," List said.
The project is one of many ''smart highway" initiatives, which rely on information from technology such as traffic sensors and roadside cameras. This experimental system, with its automatic updates, would be a bit smarter.
By almost any measure, gridlock in America is getting worse.
Once the scourge of big cities alone, traffic congestion is now common in smaller cities and suburbs. Studies have found more bottlenecks nationwide and more time wasted in traffic as commuters drive more miles.
Building new lanes can help. But for decades, state and federal transportation authorities also have pursued the less expensive option of making traffic flow more efficient.
The idea is to provide drivers with up-to-date traffic information through dedicated AM radio stations, electronic traffic signs, 511 numbers or, more recently, websites and cellphones. Traffic information is often gleaned from sensors in the pavement or from pole-mounted cameras.
This project, funded by a $1.3 million grant from state and federal highway officials and headed by Rensselaer, focuses on information collected from commuters on weekday mornings. In February, 200 volunteers who commute daily were loaned a GPS unit and a hand-held computer linked to a central server.
Drivetime information is sent each minute from each vehicle to a server, where it forms a picture of traffic flow in a 40-mile radius. Speed is computed by tracking the progress between virtual checkpoints. The hand-held computers send updates.
Each hand-held displays a map, but there is no need to look at it, thanks to a synthesized voice that sounds like a cross between a robot and the America Online Inc.'s ''You've got mail" guy.
''The driver does not have to look at that dinky little screen while they're driving," said Alixandra Demers, a graduate student working on the project.
The experiment runs through May 15. Depending on the results, the school may conduct a second, larger test.
Al Wallace, director of research for the center, said the system could be particularly attractive for small and midsize cities plagued by rush-hour bottlenecks. Setting it up would be less expensive than investing in a series of pole-mounted cameras or road sensors, he said.
The idea behind the system will be familiar to anyone who ever used OnStar or other directional devices that rely on GPS units. The added element is that it could sense if, say, a truck was overturned across the designated route, based on information from cars ahead moving slowly.
GPS is one of several technologies being studied by transportation officials and private companies looking to update traffic systems, said Neil Schuster, president of the not-for-profit Intelligent Transportation Society of America. AirSage, an Atlanta-based company, has developed a system that uses cellphones as anonymous ''traffic probes." Its first customer will be the Virginia Department of Transportation, which will use it in Norfolk this summer, company president Cy Smith said.
Schuster said the auto industry is looking closely at federally dedicated spectrum space that could host a wireless network for moving cars. ''The next big chapter in road development in the US is, how do you take all of these roads and connect them electronically?" he said.
While the Electronic Highway is barely plugged in, aspects of it already have stirred controversy. Privacy advocates worry about the misuse of information collected from road cameras, electronic toll tags, and ''black box" computer chips, which store information on speed and seat belt use.
But List notes that users who do not want to be tracked can simply switch off the GPS unit.