I-25 rush-hour traffic to flow better with new on-ramp metering system, CDOT says

Imagine I-25 being a pleasant drive

DENVER — Particles of light pulsating across worn asphalt may soon turn a crowded and clogged Interstate 25 into a more pleasant drive.

The Colorado Department of Transportation has a plan that it says will greatly improve the flow of traffic on a section of I-25 North from Ridge Gate to University after it implements a new on-ramp system that feeds cars on when there is a gap in traffic and holds drivers on the on-ramp longer when there isn’t.

“What they are going to notice on I-25 is that it will be flowing at highway speeds even during the peak hours when we have congestion now,” Peter Kozinski, Director of CDOT’s Road X program, said. “This is a new concept never deployed in North America before.”

CDOT will install devices ever 1/3 of a mile that shoots lasers across traffic. The lasers will identify natural gaps occurring in all traffic and trigger on-ramp signals to turn green to allow enough cars onto the freeway to fill the gap.

“We have a high degree of confidence this is going to work,” Kozinski said.

The on-ramp lights will turn red when enough traffic has been allowed on to fill the gap and will hold cars at the on-ramp until another gap occurs.

“The timing of the lights at the meters is going to change a little bit. It’s not going to be a set pattern,” he said.

CDOT says it does not believe holding cars at the onramp will create traffic backups onto side streets.

“We’ve done our analysis on that, and we don’t think it’s going to be any worse than currently what exists today,” Kozinski said.

CDOT is adding a lane at the on-ramp to allow more cars to enter the highway on a green light.

An additional lane will be added on the on-ramp to northbound I-25 from Lincoln, C-470, Dry Creek, Arapahoe, Orchard, and I-225, Kozinski said.

Allowing for better traffic flow is much less expensive than adding another lane to the highway, Kozinski said. The Smart I-25 project to add the smarter on-ramp metering is expected to cost $8 million.

An additional lane, with the costs of purchasing needed land through the high-value Tech Center, could be several hundred million.

The hardware needed will be installed in the coming months with the system going online after the beginning of the year, Kozinski said.

The technology is not new and has been a success according to transportation officials in Melbourne, Australia.

“Once people get on the freeway, they get a really good run,” Sameem Moslih, VicRoads’s Director of Journey Services.

VicRoads, the government road agency in the state of Victoria, Australia, has been using the smart ramp metering system since 2000.

“We’ve also had less breakdowns and much safer travel through the freeways,” Moslih told Denver7 Investigates reporter Jace Larson in a video conference. 

Data from lasers on the highway in Denver will be sent in real time to Australia where it will be analyzed and sent back to Denver to trigger the on-ramp lights.

CDOT plans to demonstrate and analyze the effectiveness of the smart ramp metering on the stretch of I-25 north initially but could expand it.

If drivers on the I-25 north stretch see improved traffic flows as Kozinski predicts, the technology is expected to be expanded to other stretches of Colorado highways, he says.

Based on the experience already seen in Melbourne, Kozinski says he has no doubt the project will be a success in the Denver area.

“I guarantee we’re going to see improvements over existing conditions,” Kozinski said.

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