CDPHE unveils proposals to reduce emissions from transportation sector, addressing the climate crisis and improving air quality

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Contact: Andrew Bare, 720-425-2736 (mobile),



REMOTE (May 20): Colorado Department of Public Health and Environment today presented a proposal for new rules that aim to reduce vehicle traffic in Colorado, cut emissions of greenhouse gases and other pollutants, and improve air quality in the state. The proposals provide Coloradans with more flexibility and options as they make transportation choices.  

CDPHE staff presented the proposal to the Air Quality Control Commission at its monthly meeting. The commission unanimously voted to schedule a rulemaking hearing on the proposal for its August meeting. 

“The transportation sector is the largest single source of greenhouse gas emissions in the state of Colorado,” said Clay Clarke, supervisor of CDPHE’s climate change unit. “And vehicle traffic contributes significantly to ozone pollution in the Front Range. We know that addressing this sector is absolutely crucial if we want to address climate change and improve air quality for Coloradans. We want to give Coloradans the tools to make smart transportation choices that are right for them and their families.”

The proposal has two components:

  • The Employee Traffic Reduction Program (“e-trip”), which is designed to provide employers and employees with flexible options to reduce the number of employees who commute to work in single occupancy vehicles. The program would require employers in the Denver Metro/North Front Range ozone nonattainment area with more than 100 employees to produce a plan to reduce vehicle miles travelled from their employees, though employers would not be penalized if employees do not meet the trip reduction goals. CDPHE estimates this will reduce greenhouse gas emissions by more than 681,000 tons per year, starting in 2025.
  • Tightening the state’s existing vehicle inspection program that requires vehicles 11 model years old or older to undergo an emissions test and meet registration requirements. The Air Pollution Control Division estimates this will reduce emissions of ozone precursors by approximately one ton per day. 

In addition to the transportation proposals, CDPHE also presented the Greenhouse Gas Emissions and Energy Management for Manufacturing rule, which would require energy audits and emissions reductions plans at four major industrial facilities in the state: the Evraz Steel Mill and GCC Rio Grande cement plant in Pueblo, the Holcim-Portland cement plant in Florence, and Cemex Construction Materials South in Lyons. CDPHE estimates this proposal would achieve a greenhouse gas emissions reduction of between 230,293 and 573,735 metric tons of carbon dioxide equivalents.

Thursday’s presentation came after extensive stakeholder outreach from both CDPHE and the Colorado Department of Transportation. CDPHE mailed roughly 3,700 letters to qualifying businesses, held 12 informational and listening sessions and two equity workshops as part of the Employee Trip Reduction Program stakeholder process.

“Reducing ozone pollution and greenhouse gas emissions are two of our highest priorities,” said Garry Kaufman, director of the Air Pollution Control Division. “Success in that work means better air quality and a higher quality of life for Coloradans. We look forward to the August rulemaking hearing on these vital proposals, and in the meantime, we’ll continue to look for other effective, scientifically driven policies for achieving these goals.”