Coordinated Adaptive Ramp Meter Pilot | Study Phase

About the Study

The Colorado Department of Transportation (CDOT) Region 1 is conducting a Coordinated Adaptive Ramp Metering (CARM) Pilot Study at ramp metering locations on northbound I‑25 between Ridgegate Parkway (Mile Post 192) and University Boulevard (MP 205). The pilot will evaluate an updated ramp metering system designed to improve traffic flow, reduce congestion and enhance safety along one of the region’s busiest travel corridors. The system adjusts ramp meter timing in real time based on traffic conditions to help reduce stop-and-go traffic and improve the safety of merging onto the interstate.

CDOT will monitor operations throughout the pilot and coordinate with local agencies and transportation partners to evaluate traffic conditions on both I-25 and nearby roadways. A previous ramp metering pilot study in 2022 found that CARM reduced crashes, shortened travel times, improved travel time reliability, and reduced total delay on the freeway corridor.

Study Area

Map of ramp meters on I-25 being used as part of the CARM pilot study.
Map of ramp meters on I-25 being used as part of the CARM pilot study from Mile Point 205 to MP 192.

Schedule & Important Dates

  • System Implementation and Fine-Tuning: Spring 2026
  • Freeway-to-freeway ramp activation: Summer 2026
  • Data Collection and Evaluation: Fall 2026
  • Pilot Assessment and Documentation: Fall 2026 to Summer 2027

 Goals
  • Evaluate, plan, and design a CARM pilot implementation on a corridor in the metropolitan Denver area.
  • Investigate and implement new technologies aimed at improving safety and reliability while mitigating congestion and delays.
  • Investigate methods for managing the increasing number of vehicles on roads and improving the energy efficiency of the transportation system without relying on increasing roadway capacity.
 System Implementation and Fine-Tuning Phase

Implementation and fine-tuning of the CARM system is scheduled to begin in June 2026. During this phase, CDOT Region 1 will be closely monitoring traffic operations in the pilot study area, troubleshooting any issues, and fine-tuning operations.

The ramp metering algorithm will be gradually adjusted over several months, and drivers may not notice any initial changes to ramp meter operations.

Starting in Summer 2026, CDOT will begin reactivating the ramp meters located at:

  • Eastbound C470 to Northbound I-25
  • Southbound (westbound) E470 to Northbound I-25
  • Southbound I-225 to Northbound I-25

CDOT will be closely monitoring these ramps to ensure the proper flow of traffic. Motorists are encouraged to stay alert and follow all posted signs and signals at the ramp meters.