How to Improve I-25 Traffic Without Spending Big Bucks

Many Colorado drivers complain about the traffic on Interstate 25 through metro Denver. But Colorado doesn’t have money to add new lanes to I-25, and even if it did, motorists would see only temporary benefits until traffic increased so much that even the new lanes would become snarled. Now, a report from the Southwest Energy Efficiency Project (SWEEP) explains how to use market forces to improve the highway for the long-term, all at a reasonable cost.

The old saying “time is money” also applies to traffic management. The more time that drivers spend in traffic on a particular road, the less likely they are to use it. Example: A decade ago, Colorado added lanes to I-25 with its Transportation Expansion Project (T-REX) and at first the time needed to drive the highway – that is, the “price” – decreased. But the lower “price” just encouraged more motorists to use the interstate.  Today, I-25 traffic jams are just as bad as they were before T-REX. 

Colorado’s population growth has added to the problem, but the issue is fundamental. Nationwide, numerous studies confirm that new highway lanes just attract more drivers and result in more jams.

But a different, affordable and long-lasting solution has been used successfully on another Colorado road: managed lanes, also known as High-Occupancy Toll lanes, have worked well on U.S. 36 between Boulder and Denver’s northern suburbs.

SWEEP’s study explains how HOT lanes can maximize efficient travel on I-25 through part of metro Denver. Its key points:

  • CDOT can convert one lane of I-25 through the T-REX area to a HOT lane;
  • The cost would be much lower than building entirely new lanes;
  • The change would take less time than adding new lanes;
  • The HOT lane can be used by cars with just one or two occupants, but as is true on U.S. 36, those cars would pay a fee; 
  • Money earned from the HOT lanes can be invested in: public transit; transit passes for commuters; expanding and upgrading biking and walking infrastructure; and additional support for carpools and vanpools.
  • Conversion of existing lanes to managed lanes, along with aggressive promotion of alternatives to driving alone, can benefit all types of travelers
  • Congestion in the remaining general purpose lanes would be no worse than before.

SWEEP Transportation Director Will Toor explains: “Colorado’s thriving economy continues to attract more people to move here, but the state and its cities don’t have enough money to keep adding new highway lanes – and even if taxpayers agreed to pay the hefty price tag, the new lanes wouldn’t solve the long-term problem. It’s time for Colorado to try a different approach.”