CDOT: Technology key to managing I-70 traffic |

CDOT: Technology key to managing I-70 traffic

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Summit Daily file photo/Mark Fox

SUMMIT COUNTY – The ways things are now on our highways, we’re almost entirely reactive. Snow falls and we plow it; accidents occur and we clean them up; traffic slows or stop and we curse. We’re just beginning to enter the era where drivers have advance information about what might lie ahead and be given the chance to be proactive.

That’s the gist of what Colorado Department of Transportation traffic engineer Bernie Guevara told the Summit County Commissioners at a recent work session. Guevara pointed to the new signs along the Interstate that let drivers know in real time how long it will take to get from, say, Silverthorne to C-470. That information is gathered from transponders in a variety of vehicles, which is fed into a computer to create an algorithm to most accurately predict those times. With more and more vehicles having transponders and feeding into that database, Guevara said, the ability to do things like predict accidents before they happen will become a reality.

“It gives you the ability to monitor speed turbulence – things we know happen before an accident,” Guevara said. “You can tell people to slow down and even speed up with variable speed-limit signs.” In some cases, he said, the message is “slow down to get there faster.”

To get drivers to cooperate with such advanced sign technology, though, takes trust. Tony DeVito, director of CDOT’s Region 1 – which includes Summit County – said the new travel-time signs are part of that.

“People rely on them, they believe they’re correct, so we’re laying the groundwork,” he said.

At the heart of what CDOT would like to do along I-70 is something called “active traffic management.” You take real-time information from cars along a road, feed it into a central information system, then make it available to drivers along the whole route. One simple example of this is the new truck parking area near Dotsero. When Vail Pass is a mess, CDOT puts out the word and gets truckers to sit it out down valley rather than head up the pass to gum up the works even more. Another such parking lot is being set up east of Denver for the same reason.

In more sophisticated models of active traffic management, Guevara explained, a driver just a few hundred yards from a fresh accident could get an alert – say when the transponder in the wrecked car suddenly indicates the speed went from 60 mph to zero.

In Seattle, the city has some $30 million to put toward active traffic management, with high-tech signs going in this past year on Interstate 5. As one Seattle Times reporter put it, the signs “… will dictate lower speed limits when traffic farther north is sluggish. The idea is to create a smooth flow, rather than have drivers hurtle 60 mph toward a 10-mph glob of traffic entering downtown.”

Along I-70, fiber optic cable installed a few years ago as far west as Vail has made the travel-time signs possible, and that conduit would provide the backbone of a more advanced system in the future. New adjustable speed limit signs recently installed along the Interstate are currently only to be used when the chain law is in effect, according to CDOT.

“Having some of these digital signs for use during the chain law is part of it; we’re taking baby steps,” DeVito said. “Ultimately we’d want to have a full matrix of information with the ability to use different speed limits.”

Commissioner Bob French expressed skepticism that people paid much attention to any speed limit signs – digital or traditional. Again, Guevara said it will boil down to whether drivers can learn to trust that such signs are credible – or “smart.” If they don’t, then they’ll drive to the conditions, as they always have.

With money in short supply outside those projects funded with federal stimulus dollars, CDOT’s goal in the near term is to continue collecting data. Guevara said the stretch of Interstate between Bakerville and Silverthorne is being studied now, with information to be gathered this winter about how traffic behaves in all kinds of different conditions: snowy, icy, etc., along with different combinations of those scenarios.

“We’re looking at the actual speeds people drive, collecting speed and weather data – all to create an algorithm,” Guevara said.

Creating a more complete active traffic system along the most problematic stretches of I-70 would take a lot of money – but conceivably still a good deal less than adding lanes or building some kind of railway. With most current highway dollars coming from the tax on fuel, Commissioner Thomas Davidson wondered after the meeting what will happen when high MPG – and even electric cars – are the norm.

“Where will the money come from for highways?” he said.

For an interactive demonstration of how active travel management might work,

Summit Daily editor Alex Miller can be reached at or

(970) 668-4618.

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