US 36 Express Lanes Project

Please Note: Tolling has begun on US 36! Whether you plan on driving solo or as an HOV on the US 36 or I-25 Express Lanes, it's important to get a pass so that you can use these lanes. Create an ExpressToll account here, and order your pass today! For tolling or billing questions, please call 303-537-3470.


US 36 between Denver and Boulder opened as a toll road in 1951. The toll road bonds were paid off early and the tolling infrastructure was removed in 1968. When it was built, this four lane road had only one interchange between Denver and Boulder. In response to rapid population growth, there are now 10 interchanges along US 36 between I-25 and Boulder. However, the number of main through-lanes has remained at four.

In December of 2009, the Colorado Department of Transportation completed an Environmental Impact Statement which described Preferred Alternative improvements to the corridor which would be implemented in the future as funding became available. The main elements in the Preferred Alternative include one buffer-separated managed lane in each direction, Bus Rapid Transit (BRT) ramp stations, auxiliary lanes between most interchanges, and a bikeway.

These two projects will be the first steps in implementing improvements described in the US 36 Environmental Impact Statement.

CDOT Update on US 36 Public-Private Partnership: Understanding the Facts

The public asked CDOT for more details about the upcoming public-private partnership (P3) for the US 36 corridor.  We wanted to take this opportunity to explain what is happening with the P3 and the contract as there has been a lot of misinformation released. Read more here...

US 36 Public-Private Partnership Concession Agreement

CDOT released the concession agreement for the US 36 corridor on February 14, 2014, upon further discussion with its partner Plenary Roads Denver.  The document contains the contract provisions, standards of service and other agreements to which each agency will be held.  It also includes 27 schedules which describe agreements ranging from maintenance, to construction requirements.  Four of the schedules are summarized at the request of Plenary Roads Denver due to the proprietary information. The documents can be found on the CDOT website at:

Colorado: The Official State Web Portal