TORONTO - The line of blinking lights along the side of the road may look like what Americans see in the form of orange construction barricades, but they're a key tool in a highway safety experiment being carried out in Scotland, Bavaria and Italy.
The European program is attempting trying to develop ways not merely to alert motorists of danger, but to communicate what the caution actually is.
The test is using mile after mile of light-emitting diode roadside flasher posts. The LED posts use different colors of light or flash patterns to give drivers a clue to dangers or traffic changes that may lie a mile or more ahead, ranging from a stalled vehicle to a car coming the wrong way on a limited-access road.
'We're developing a system where the flashing lights become a message to motorists,' said Steve Tarry, an engineer for the Companion Incident Management System. German experimenters informally have dubbed the system 'blinking lights.'
Tarry discussed the effort at the sixth World Congress on Intelligent Transport Systems last month in Toronto.
The system was activated in September 1998. Its intent is not just to prevent accidents but to minimize so-called 'secondary' accidents - those that happen in snarled, chaotic traffic that builds up behind an initial accident.
The system could be used to prevent the simple but frustrating congestion around a broken-down car on the freeway median.
The LED posts are controlled by traffic enforcement agencies that already use closed-circuit TV to monitor the roads. When the TV reveals an accident, a weather-related problem or road congestion, dispatchers immediately can activate the light system to warn drivers.
Each of the thousands of light posts has a separate electronic address, meaning the dispatcher can issue a warning at a precise distance from the traffic situation. If the problem is a moving one, such as a wrong-way driver or a growing mass of stopped traffic, the warning zone can move along with it.
Researchers have found that using a few simple flash patterns or color changes works better than trying to develop many exact warnings. A wrong-way-driver alert may be a flow of flashes back along the roadway, for instance, or closeness to an obstruction may be shown with a change of LED color from yellow to orange.
Tarry and others said the lights already have helped to harmonize traffic flow, reduce speed differences between vehicles and to build driver confidence in the road system itself.
'The traffic flow is smoother when the system is operational, and there's more of a perception of safety,' said Danilo Fum, a psychologist based at the University of Trieste, Italy, who has helped analyze the driving process with the Companion system in place.
Fum said the study has revealed an unexpected gap in driver knowledge. Some drivers find they do not know what to do when a lane is closed ahead or what evasive action to take in an emergency.
'People who take a plane have a lot of safety information, what to do in an emergency,' he said. 'People who drive along the motorway have absolutely no idea what to do.' he said.
Fum said the study showed that driver patience increases when warnings come early, are timely and give even modest information about what is ahead.
'Drivers reduce speed most when the information is salient, where they know a lane is closed ahead,' he said.
Said Tarry: 'It's had a very positive impact. Drivers become part of a platoon of traffic, rather than driving as individuals.'
While the testing continues, he said, the Scottish system already has improved drivers' perceptions of safety. Sixty percent of those surveyed said they thought the road had become much safer. The project has helped reduce speeding through the Edinburgh area test area by 15 percent to 20 percent. The system there is activated an average of eight times a month, although in December 1998, activations reached a peak of five times each week.
No trials of the system have been suggested for the United States so far, but Companion researchers expect interest in the system to build as the results become known.