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- The Federal Highway Administration awarded Utah nearly $40 million to implement a new ramp metering system on I-15.
- Coordinated adaptive ramp meters rely on a network of sensors and software to optimize freeway entry, improving congestion and travel times.
- Construction for the system is set to begin in 2027.
TAYLORSVILLE — It's not uncommon for drivers to experience traffic backups and congestion on I-15 through Salt Lake County, but Utah is now next in line to adopt a ramp metering system that could improve travel times.
The Federal Highway Administration recently awarded the Utah Department of Transportation nearly $40 million through its Congestion Relief Grant to implement a coordinated adaptive ramp meter system, or CARM, along southbound I-15 from state Route 201 connection in South Salt Lake to 14600 South in Bluffdale.
UDOT officials said Wednesday that planning is now underway to implement the system in the future, which will make it one of the first in the nation to adopt the technology that was first implemented in Australia.
"We're really excited about this because it really gives us an opportunity to optimize and make our freeway system — one of our most valuable assets — more efficient without adding any additional capacity," said Grant Farnsworth, UDOT's freeway operations manager.
CARM would replace the traditional method of ramp meters that dictate when drivers enter the freeway. UDOT officials say those rely on on-ramp traffic signals and sensors that regulate when drivers are allowed onto the road.
The only problem, Farnsworth said, is that it doesn't solve problems when there's heavy congestion. Vehicle capacity normally on I-15 typically drops from 1,900 vehicles per hour per lane to 1,250 during peak travel hours.
CARM, on the other hand, relies on a "dense amount of sensors" that feed information about the number of vehicles using all of the ramps in the system to a software program. This is all done instantly through constant 20-second intervals, adjusting when drivers are allowed onto the freeway at each ramp.
He said it's expected to improve wait times for those trying to enter the freeway, as well as overall congestion.
UDOT has talked about the technology for "some time," even meeting with experts from Australia, where the system originated, Farnsworth added. Utah transportation officials also communicated heavily with peers at the Colorado Department of Transportation, which began testing CARM on a section of I-25 southeast of Denver two years ago.
Colorado transportation officials noted that they had become interested in the system when Melbourne, Australia, transportation officials reported a 25% increase in traffic flow, as well as a 35%-60% increase in vehicle speeds during peak travel times after switching metering methods.
Farnsworth said he hopes Utah will be able to enjoy similar success, but that isn't expected to happen right away. UDOT officials said construction will begin in 2027 before it's ready to go sometime after that.
"It's all about making the freeway system work better," he said. "It helps all users of the freeway system to enjoy and more reliable, safer experience when they're on the freeway. It will be able to accommodate those people on the freeway and also those getting on the freeway."
