If You Build It, the Cars (and the Pollution) Will Come

RMI analysis indicates that Colorado's plan to add nearly 200 new highway lane-miles by 2030 could induce 1 to 1.5 billion additional annual vehicle miles traveled (VMT), equivalent to adding 70,000 more vehicles to the roads each year. The report argues that road expansion fails to provide long-term congestion relief because travel demand increases proportionally to new capacity, a phenomenon known as induced travel. These expansions are estimated to increase cumulative direct and upstream greenhouse gas emissions by 8 to 15 million tons of CO2-equivalent through 2050, costing over $3 billion in direct project costs. RMI advocates for shifting investment toward public transit, micro-mobility, and compact, mixed-use community development to achieve a 10 percent reduction in VMT by 2030.

• Road expansions in Colorado's urbanized areas are estimated to increase traffic by 2 to 8 million VMT per year for every new highway lane-mile added. Using a conservative midpoint, each new lane-mile corresponds to approximately 400 additional cars and SUVs annually and the carbon pollution of 200,000 gallons of gasoline.
• A portfolio of 176 planned and in-progress highway lane-miles in Colorado could result in 1 to 1.5 billion additional VMT per year by 2030, representing a 2 percent increase over current levels and adding the equivalent of 70,000 more vehicles annually.
• The planned road expansion projects in Colorado are projected to increase cumulative direct and upstream greenhouse gas emissions by 8 to 15 million tons of CO2-equivalent through 2050, with total direct project costs exceeding $3 billion.
• General research indicates that congestion reductions from road expansions are temporary, typically disappearing after 5 to 10 years as drivers increase the frequency and length of trips to utilize the new capacity.

APA

RMI (2021). If You Build It, the Cars (and the Pollution) Will Come. https://rmi.org/resources/if-you-build-it-the-cars-and-the-pollution-will-come/

Chicago

RMI. If You Build It, the Cars (and the Pollution) Will Come. 2021. https://rmi.org/resources/if-you-build-it-the-cars-and-the-pollution-will-come/.

Wikipedia

{{cite report |author=RMI |title=If You Build It, the Cars (and the Pollution) Will Come |date=21 April 2021 |url=https://rmi.org/resources/if-you-build-it-the-cars-and-the-pollution-will-come/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2021you, author = {{RMI}}, title = {{If You Build It, the Cars (and the Pollution) Will Come}}, institution = {RMI}, year = {2021}, month = apr, url = {https://rmi.org/resources/if-you-build-it-the-cars-and-the-pollution-will-come/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }