CDOT is testing a new ramp metering system on northbound I-25 between Ridgegate Parkway and University Boulevard, with the goal of reducing congestion.  Motorists may notice a difference in the timing of the lights when they approach the ramp meters.  The signals are updated in real time based on actual traffic conditions every 20 seconds to better control the flow of traffic entering northbound I-25.   This is expected to result in faster travel times on northbound I-25. The project team is closely monitoring the new system and making adjustments and improvements as needed.   

Most of the ramps continue to have two ramp metering signal lights, but there are some ramps that have an additional signal.  Three new signals have been installed at the westbound Lincoln Avenue, Dry Creek Road and westbound Arapahoe Road on-ramps to northbound I-25.  The right shoulder lanes can be used on these ramps when the ramp metering signals are on.  See image below and watch the video on how the new ramp metering system works.  

In mid to late February, this new ramp metering system will be extended to I-225, C-470 and E-470 on-ramps to northbound I-25.   More communications will be shared once the dates are confirmed for activating the ramp metering system on these ramps. The system will be closely evaluated.  If results show traffic conditions improve, permanent deployment is possible. 


This system has worked successfully in Melbourne, Australia, resulting in reduced congestion, improved travel time reliability, reduced crashes and reduced emissions.  

More info below: 

Webpage (including a fact sheet and video) 

Smart 25 Pilot Project: Coordinated Ramp Metering System on I-25 from Ridgegate Parkway to University Boulevard — Colorado Department of Transportation (