How to Improve I-25 Traffic Without Spending Big Bucks

July 14, 2017


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.”