Advisory speeds, real-time information designed to improve safety, reduce congestion
New signs designed to improve safety, reduce secondary crashes and provide drivers with real-time travel information were switched on Tuesday morning along Highway 217.
The signs are the latest in a series of Oregon Department of Transportation projects that use new technologies to smooth traffic flow on one of the area's busiest highways. On July 10, ODOT began using signs that display estimated travel times to key destinations.
That information appears on seven full-color, 30-foot wide LED signs, four in the southbound lanes and three in the northbound lanes. Travel times also are displayed on five smaller signs on roads leading to Highway 217, including one on Kruse Way.
On Tuesday, ODOT activated two new components to its RealTime system, which will be updated every minute:
Advisory speed signs display an advisory speed based on the traffic ahead. As traffic gets worse, the signs display slower and slower advised speeds. If traffic is flowing normally, the signs won't display anything, but once traffic slows below 50 miles per hour, the new advisory speed signs will tell drivers to slow down before they reach problem areas.
Traveler information signs alert drivers to crashes, congestion, road conditions, closures and other traffic-related information. Signs will tell drivers where the backup begins, rather than the location of the incident that is causing it.
"The whole point is to give drivers the information to start slowing down before they reach the line of backed-up cars, which will defintely reduce rear-end crashes," said Karen Dinwiddie, a spokeswoman for ODOT.
The signs were installed last year, Dinwiddie said, and ODOT has spent the past several months finalizing the software.
In the past, signs would say where a crash is, but these will say where the backup starts, Dinwiddie said. That way, drivers can anticipate hitting the backup and make a decision about whether they want to stay on that road.
More than 270 crashes occur on Highway 217 every year, Dinwiddie said. Of those, more than 70 percent are rear-end crashes. National studies show that advisory speed signs have reduced overall crashes by 20 percent, reduced rear-end collisions by 30 percent and reduced secondary crashes by 40 percent, she said.
A study of the highway in 2009 looked at several options for reducing congestion, including closing on-ramps or adding additional lanes.
We took a holistic approach, beyond just widening the road, and we realized we needed to best use the road that we have," Dinwiddie said, adding that the cost of adding lanes to Highway 217 could be as much as $1 billion.
"This was an alternative to widening the highway, which we dont have the money to do, she said.
Dinwiddie said plans are in the works to add the signs to the Interstate 5/Interstate 405 interchange, as well as to the Marquam Bridge this summer. Highway 26 near Mt. Hood could also see the signs in the next few years.
For more about ODOT's RealTime projects, check out the video at www.youtube.com/oregondot.
Reporter Geoff Pursinger contributed to this story.