By Photo: David Shankbone / Wikimedia Commons, CC BY 3.0
For years the stretch of Interstate 25 between Denver’s northern suburbs and Fort Collins was the bottleneck every Northern Colorado commuter knew. The Colorado Department of Transportation has been rebuilding it in segments since 2019. Here is where the work stands and how the new lanes work.
What’s open
The Berthoud to Fort Collins section, from Colorado 56 in Berthoud to just past Prospect Road in Fort Collins, is complete. CDOT added a general-purpose lane and a tolled express lane in each direction, rebuilt interchanges and bridges and added park-and-ride mobility hubs. The express lanes opened in December 2023 and are now tolling. CDOT counts about 47 lane-miles of express lanes in this section, both directions combined.
What’s under construction
The last gap is the roughly six-mile Mead to Berthoud section, from Colorado 66 to just south of Colorado 56 in Weld County. Construction began in May 2024. The $415 million project adds an express lane in each direction, widens shoulders, rebuilds the Weld County Road 34 interchange and replaces several bridges. CDOT expects to finish in 2028. When it is done, I-25 will have more than two lanes in each direction all the way from Denver to Fort Collins for the first time.
Expect lane shifts and overnight closures in the work zone. CDOT’s speed-camera program is active there, and drivers caught going well over the limit receive civil fines.
How the tolls work
- The lanes are open 24 hours a day. Tolls change by time of day and are posted on overhead signs.
- Drivers pay through an ExpressToll account with a transponder or by license-plate toll, which costs more.
- Carpools of three or more people ride free, but only with an ExpressToll account and a switchable HOV transponder set to “HOV.”
- Motorcycles ride free without a pass, and buses use the lanes.
- Enter and exit only where the lines are dashed. Crossing the double solid white lines brings a ticket, starting at $75.
Transit
CDOT’s Bustang intercity bus runs between Fort Collins and Denver and uses the express lanes. The new mobility hubs along the corridor give riders park-and-ride lots and bus stops in the median or next to the interchanges.
Check before you drive
CDOT posts weekly lane closures on its project page and live conditions on COtrip.org. For mountain routes in winter, see our guide to Cameron Pass, the Snowy Range and winter road sources.
Sources
- CDOT, I-25 North Express Lanes, Mead to Berthoud: project facts and schedule.
- CDOT Express Lanes program, I-25 Berthoud to Fort Collins.
- CDOT news release, December 7, 2023.
