A 25-mile section of Interstate 90 is being wired to see whether modern electronics can make driving safer over Snoqualmie Pass.
The test project will feature small weather stations along the route, electronic signs flashing safe speed limits that vary according to road conditions, and portable display screens on drivers’ dashboards.
The rate of accidents over the 3,020-foot Cascade Range pass is 2.3 times the year-round rate from December through February, and often five times the norm during snowy weather.
Those accidents often involve rear-end, side-swipe and run-off-the-road accidents, indicating motorists not only speed but travel at widely differing speeds during poor conditions, according to the Washington State Transportation Center, the state-supported research agency conducting the study.
“That’s where you have cars with chains traveling 35 mph and other vehicles that don’t slow down and run up behind them real fast,” said Larry Senn, a traffic systems engineer with the center.
Beginning in June, the system will be set up to include:
Six mini-weather stations to collect data, including road surface conditions, that will be fed into a computer at a control center at Hyak.
32 roadside radar devices, similar to those used by police to track speeders, which also will feed data to the computer.
13 message signs that will display the safe traveling speed - as determined by the computer - along with any pertinent road conditions, such as accidents.
Portable display screens supplied by the state to nearly 200 cars and trucks that regularly travel the pass. The screens will receive the same information as the message signs, and will display a Snoqualmie Pass map to help the driver pinpoint road conditions and problems.
Portable transmitters carried by Washington State Patrol troopers and snow plow operators also will send safety-related messages to the dashboard receivers.
The study, dubbed “Travel Aid,” will also try to determine whether motorists heed the safety messages and varying speed limits. The same roadside sensors and computer that measure traffic speed will measure drivers’ responses.
“Some people will slow down, but is this 5 percent, 20 percent or 80 percent?” asked Mark Hallenbeck, a University of Washington faculty member who helps run the center.
Some preliminary human-response testing will be done at the University of Washington, where the driver of an automobile simulator will look up at a screen and read such signs as “accident ahead in five miles … move to the right lane” - with the message obscured by what appears to be heavy snow or fog.
Researchers also will test the portable screens to see whether they distract drivers.
The results of the test are expected to be known in mid-1997, and much of its success is expected to depend on the accuracy of the information the equipment collects and transmits.