Interstate 70

Issue and need:
I-70 is a critical artery between the metro area and the Western Slope that links many Coloradans to the outdoor lifestyle that caused many of us to move here. It is also the primary route for the east/west movement of goods across the state. Peak times of travel are no longer as predictable or avoidable as they were in the past. Full day commutes are no longer reserved for busy holiday weekends. In fact, during the winter of 2013-2014, there were multiple weekends with reports of eight hour drives or longer for those who were returning from mountain visits over the weekend.


The initial approval of I-70 was authorized in 1944 to run between Denver and the Kansas state line. As part of the initial approval, no mileage was allotted west of Denver, due to Utah’s lack of interest. The portion of I-70 that runs between Denver and the Western Slope was approved later as part of the 1956 Interstate Act. I-70 is a federal highway that has had large investments over the course of its life, including the completion of the Eisenhower Tunnel and expansion through Glenwood Canyon. I-70 generally serves two very different users—the leisure traveler and the worker moving goods or services.

The challenge of the volume of traffic on I-70 has been recognized for generations. To solve this issue, there needs to be an expansive solution that requires significant investment. Some less costly solutions, like pace cars to manage congestion at peak periods, have proven ineffective. Some of the more significant solutions that been proposed over the years include:

  1. Expanding the number of lanes. This is expensive given development that is close to the current highway and the tunnels and topographical limitations for expansion.
  2. Putting in a monorail or train system. Fixed rail systems are extremely expensive to put in place and to make financially viable given ridership.

In 2005, a study was conducted (the Chamber funded this effort) that found the cost of congestion is estimated at $839 million a year. An environmental impact study was conducted in the last decade and a record of decision was established which found that current technology would allow an Advanced Guideway System (mag lev) to operate in the corridor. The estimated cost of a mag lev system is $18 billion. There is not strong agreement that this record of decision presents the most viable option for addressing congestion on I-70 (the cost alone causes some to believe it is an unlikely solution).

A number of recent actions have been taken to improve mobility:

  1. An eastbound lane was added to the twin tunnel at Idaho Springs.
  2. A westbound lane is currently being added to the twin tunnel at Idaho Springs.
  3. An eastbound Peak period shoulder lane is being added from Empire to the Twin tunnels and is expected to be completed by October 2015. (This is a tolled lane with the rate established based on demand.)
  4. CDOT is exploring if it can create a westbound peak period shoulder lane and hopes to have funding plan in place by the fall of 2014.
  5. CDOT plans to run a bus service from Glenwood Springs to Denver Union Station one way each day with a few stops along the corridor to lessen car traffic. They also have placed an effort to increase awareness about current bus service (Front Range Ski Bus and the Colorado Mountain Express).
  6. An effort was established to shift travel times and encourage people to stay in the mountains through Sunday night or travel later on Sunday. (
  7. Discussion is starting again on alternative routes into the mountains such as 285 (Hampden).


  • Lack of funding: The solutions to address this challenge are very costly and require funding sources significantly larger than can be raised with current tax dollars. We also know through recent public opinion polling that Coloradans don’t have an appetite for a tax increase at this time.
  • Lack of alternative routes makes construction more challenging.
  • Inclement weather and geographic barriers also complicate execution of infrastructure improvements.

Potential solutions:

  1. Begin establishing a forum for statewide conversations to address this issue.
  2. Examine alternative routes into the mountains – 285 (Hampden) on the southern end.
  3. Land events that might help create the impetus for a solution, e.g., Olympics.