Ramp Meter Now Operational on US 85 (Santa Fe Drive) Ramp to Northbound I-25

DENVER—On Monday, Nov. 20, CDOT officially turned on the ramp meter at the US 85/Santa Fe Drive ramp to northbound Interstate 25, making it fully operational. This ramp meter will help ease congestion and improve the flow of traffic on northbound I-25.

A pilot implementation of this ramp meter was conducted in July 2014. The pilot project observed significant improvements in system travel times during the weekday off-peak period (20 percent reduction in travel time) as well as more modest improvements in the evening rush hour (seven percent reduction in travel time). As a result, the ramp meter will only be turned on during these time periods and will not be used during the morning commute, unless additional testing shows otherwise.

"In coordination with other ramp meters along northbound I-25, we expect to see a 15 to 20 percent improvement in volume, and a 15 percent reduction in crashes based on research in Colorado and nationwide," said Angie Drumm, CDOT's Denver Metro area deputy director of transportation systems management and operations.

Ramp metering systems (the traffic signals located along entrance ramps to highways) 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 in the evening during the week.

During the first several days of operation, CDOT will actively monitor and adjust the metering to more optimal timing to balance ramp backup with freeway flow. Ultimately, the ramp should never end up with unserved demand that would cause extreme congestion on the cross street, Drumm said.

Several other ramp meters exist in the Denver metro area. I-25 and C-470 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 seven miles per hour.

Ramp meters have also decreased rear and side crashes by about 50 percent in the Denver area.

CDOT is optimistic that ramp metering at the US 85 ramp to northbound I-25 will improve safety and the flow of traffic, especially as the population continues to grow.