Ramp Meters to be Installed on Three North I-25 On-Ramps Starting Monday

NORTHERN COLORADO—Drivers along I-25 will be seeing some new red lights soon, but these are intended to keep traffic moving.

The Colorado Department of Transportation (CDOT) will begin installing ramp meters on northbound and southbound ramps at CO 392 (Carpenter Road), and on the southbound on-ramp at Harmony Road starting Monday, March 13. The project is expected to be completed mid-May.

Ramp metering systems (the traffic signals along entrance ramps to a highway) allow traffic to enter a highway at a rate dependent upon the conditions of highway traffic. While motorists may experience some delay at the meter, highway speeds, safety and overall travel times are improved. Metering will only take place during high-volume times in the morning and evening during the week. Exactly when the meters will go into effect will be determined in the field and adjusted as needed.

Ramp metering is in place in several areas around the state, but these will be the first ramp meters in northeastern Colorado.

Benefits of Ramp Metering

I-25 and C-470 in the Denver area provide an example of the positive benefits of ramp metering. After the installation of ramp meters on a section of southbound I-25, the average speed increased 31 percent—or 8.6 miles per hour. On the C-470 section, travel speed was increased an average of 10 percent—or 7 miles per hour.

Safety is also an issue. Ramp meters have decreased rear and side crashes by about 50 percent in the Denver area. And the study in 2014 showed, for example, that 47 of the 48 peak-period crashes near the southbound ramp at Harmony Road happened during the evening commute period.

Determining Locations

The locations for installation were selected following the results of a ramp-metering feasibility study completed in 2014, which showed these three locations were the only ones along I-25 that would benefit the flow of traffic on I-25. Funding for the $440,000 project was made available for this year.

"While the original study done in 2014 showed ramp meters were warranted at these three locations, a follow-up study has now shown that every ramp on I-25 from Johnstown to Fort Collins could use ramp meters," said Larry Haas, CDOT regional traffic operations engineer. "That's how quickly our population and traffic congestion have grown."

Additional ramp meters may be installed as part of the North I-25 Express Lanes project (expected to begin construction at the end of this year or beginning of next year), but no determination has been made if that will be possible.

Installation of the ramp meters should have minimal impact on traffic. Work will be done on the ramps from 7 a.m. to 5 p.m., Monday through Friday. Ramp traffic will be moved to the shoulder but should not be impacted.