Colorado leaders must kick their road-widening addiction to enable a livable future

Highway expansion is bad environmental policy

April 27, 2021 11:30 am

Cars head south on Interstate 25 in Denver during rush hour traffic on on July 23, 2020. (Quentin Young/Colorado Newsline)

As Coloradans grapple with the consequences of climate change on our state, political leaders have introduced climate-focused priorities into many plans and guidelines. Most recently, this appeared in a state legislative proposal on transportation funding, which highlighted the role of electric vehicle infrastructure and traffic congestion relief in Colorado’s Greenhouse Gas Pollution Reduction Roadmap.

However, the projects and funding listed in the Legislature’s proposal do not reflect those priorities. Instead, they reflect a chronic addiction to road and highway construction, a condition which demonstrably causes further traffic congestion and precedes environmental destruction — destruction which Colorado has already viscerally experienced.

The Legislature’s proposal displays front and center its goal to “reduce traffic and congestion through improvements to key corridors.” For any Colorado driver, this appears to be a desirable outcome: Traffic, commute times and parking are all major topics in local political discourse, and we feel the stress of driving and sitting in traffic every day. Road and highway construction is an integral part of local and statewide spending, yet congestion remains a problem.

Why is that?


The answer is a principle called induced demand. Induced demand shows us that expanding roadway capacity causes people to choose driving as their mode of transport more often, because expanded roadway capacity makes driving more convenient. This leads congestion and pollution to return and worsen after only a few years.

In 2006, Colorado saw Interstate 25 heavily widened through Denver with the $1.67 billion T-REX project, but congestion returned to pre-expansion levels within five years. The effects of future roadbuilding projects are just as predictable: The Rocky Mountain Institute estimates that the state’s planned roadway expansion projects would bring the equivalent of 70,000 more vehicles on the road, with an accompanying increase of 8 to 15 million tons of greenhouse gases, all within the next 10 years.

Expanding roadway capacity causes people to choose driving as their mode of transport more often, because expanded roadway capacity makes driving more convenient.

But isn’t roadway expansion good for the environment, since congested roadways cause drivers to sit in traffic and pump out more pollution? This is a common position among roadbuilding advocates, such as the group Fix Colorado Roads and the Colorado Department of Transportation itself. However, research shows the opposite: The increase in pollution from induced demand after expansion outweighs the previous levels of pollution on a congested roadway. A study found that “congestion mitigation does not inevitably lead to reduced emissions.” Roadbuilding is bad environmental policy.

If we choose to widen roads as soon as they become congested, we pretend that there is unlimited room for roads, and that there are few downsides to expansion. But huge amounts of space have already been taken and the downsides are extremely clear.

The Legislature’s proposal is a reflection of the 20th century American addiction to building roads. That addiction has created harsh air pollution in Colorado today and is paving a road for further destruction through climate change, through impacts we have already experienced, such as extreme wildfires, storms and droughts. Our concept of transportation planning is killing us and burning our home. And we are still stuck in traffic.

In fact, the reason that Coloradans are stuck in traffic all the time is because Coloradans who would prefer to use a different mode, like walking, biking or taking transit, don’t have access to those safe, efficient options, options that reduce congestion by taking cars off the road. When our choice between driving and non-driving options is out of balance, the result is an oversized focus on road expansion, which leads to more congestion for everyone.

This issue is compounded by land use policies that practically enforce automobile usage and create inefficient, unsustainable sprawl. Coloradans would love to be able to walk or roll to their jobs or their favorite restaurants and shops, but our policies require homes and commercial areas to be strictly separated, increasing the amount of driving.

We should shift our policy and budgetary priorities to allow Coloradans to step away from their cars, reducing the need for vehicle ownership and emissions-intensive trips. For the same price as highway expansion, we could fund all 10 of RTD’s proposed regional bus rapid transit projects. This choice would increase mobility and safety in the region and act as a substantial positive contribution towards air pollution and climate goals.

Leaders must kick their addiction to the road widening formula, which has proven to only cause more congestion and more air pollution. Colorado deserves a modern transportation system. Until we can prioritize other options that will enable people to drive less, roadway expansion must not receive one more cent.


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Evan Derby
Evan Derby

Evan Derby is a transportation, housing, and land use advocate. He grew up in Boulder and graduated from the University of Denver in 2020. Today he works as a software engineer.