Some Colorado express lane prices will now fluctuate based on traffic, not time of day

DENVER (KDVR) — If you frequently drive along the Interstate 25 South Gap or Interstate 70 Mountain Express Lane Corridor, starting Monday, you will see "dynamic tolling" as prices fluctuate depending on real-time traffic conditions.

According to the Colorado Department of Transportation, beginning Monday, Nov. 25, drivers will see real-time pricing along the 18-mile stretch of the I-25 express lanes from Monument to Castle Rock, and on the westbound 12-mile stretch of the I-70 express lanes from the Veterans Memorial Tunnels to Empire.

The new pricing program is known as "dynamic tolling." CDOT said the tolls will automatically adjust based on real-time traffic conditions instead of by the time of day -- how it previously used to fluctuate.

CDOT said the new system better manages demand during peak hours and maintains the flow of traffic on the South Gap and mountain express lanes.

“Our studies have shown dynamic tolling is helping maintain minimum speeds on the Central I-70 Express Lanes between I-25 and Chambers Road in Denver,” said Piper Darlington, director of the Colorado Transportation Investment Office, the division of CDOT that owns and operates Colorado Express Lanes. “With the amount of traffic that the South Gap sees, we want to ensure that minimum speeds are maintained and drivers have reliable travel times.”

The department assured drivers that the pricing will be similar to the time-of-day pricing they are used to. According to CDOT, tolls on the South Gap range from $1.50 to $4.75; the mountain express lanes range up to $9.

The only difference is that the toll rates may change throughout the day to respond to the conditions, meaning prices may be higher at times drivers aren't currently used to.

"Rates may be updated as often as every five to 15 minutes, and overhead signs will display current toll prices. The price displayed when vehicles enter the Express Lanes is the price drivers will pay if they have an ExpressToll pass, even if the toll changes while the driver is traveling in the Express Lanes," said CDOT in a press release.

Those who do not have an ExpressToll pass will still pay the license plate fees. Motorcyclists, commercial transit vehicles and vehicles with three or more passengers and a switchable HOV transponder can continue to use the I-25 South Gap express lanes for free.

Drivers who want to use the express lanes can purchase an ExpressToll pass and save an average of 40% on toll pricing, CDOT said. The passes can be purchased online.