I-25 South Gap, section of I-70 freeways to begin dynamic tolling

Starting later this fall, the Colorado Department of Transportation will begin implementing dynamic tolling — changing rates based on real-time traffic rather than time of day — on two sections of the Colorado highway.

The new real-time toll will affect highway lanes along a 18-mile stretch of Interstate 25 between Monument and Castle Rock. Dynamic tolling will also begin on the western 12-mile stretch of Mountain Express Lanes between the Veterans Memorial Tunnel and Empire.

CDOT originally said the new tolls would begin Nov. 1, but later sent a correction saying it would begin later this fall at an unknown date.

CDOT representatives say the toll shift will not mean a significant change in toll prices from the regular time of day. On the South Gap of I-25, prices range from $1.50 to $4.75. The Mountain Express Lanes can cost up to $9.

The change will involve traffic patterns that may fall outside the typical busy and quiet hours for each lane. CDOT said in a statement that the toll “may be slightly higher or lower than drivers are accustomed to.”

Above-ground signs indicate toll prices, which can be adjusted every 5 to 15 minutes. The price a driver pays is the price he sees when he enters the express lane, regardless of whether it has changed while driving in that lane or not.

Those without an ExpressToll pass will still have to pay an additional license plate fee.

CDOT says real-time pricing adjustments will help keep traffic flow reliable on these two busy highway corridors.

“To keep traffic flowing, expanding dynamic tolling to these two corridors makes sense,” said Piper Darlington, director of the Colorado Transportation Investment Office, the division of CDOT that owns and operates Colorado Express Lanes.

“The South Gap and Mountain Express Lanes are two of the most traveled corridors in the state, and we want to do everything we can to keep Express Lane speeds reliable. By moving to dynamic tolling and adjusting tolls based on real-time traffic conditions, we can do just that.”

Dynamic tolling was first introduced earlier this year on the Central 70 Express Lanes. CDOT plans to eventually transition all highways in the state to dynamic tolling.

Tolls on I-25 highways in the South Gap began earlier this year. Prices are tied to the time of day, with historically higher traffic times associated with higher prices. Tolls were collected for a two-year trial period after the express lanes opened in December 2021.

With the new pricing system, the I-25 South Gap Express Lanes will still remain free for motorcyclists, commercial vehicles and vehicles with three or more passengers and a switchable HOV transponder.

All vehicles, including motorcycles, are tolled on the Mountain Express Lanes.