Colorado to adopt California’s vehicle emission standards as EPA considers rolling back regulations

Traffic congestion on I-25 northbound. (Photo by John Herrick)
Traffic congestion on I-25 northbound. The Trump administration finalized new rules on March 31, 2020 to rollback vehicle emissions standards. (Photo by John Herrick)

Gov. John Hickenlooper signed an executive order Tuesday to ensure vehicles sold in Colorado meet current emissions standards even if the Trump administration decides to slash regulations for the automobile industry.

The executive order requires Colorado to adopt California’s limits on greenhouse gases that spew from tailpipes. California has a legal waiver under the Clean Air Act that allows it to have more stringent emission standards than those set by the federal government. Colorado will join a dozen states, including California, and the District of Columbia seeking to lock in place current Obama-era vehicle emission standards.

Those 2012 standards are designed to lead to more fuel-efficient vehicles on the market in coming years. New cars, light trucks and SUVs will have to average 55 miles per gallon come 2025, a rule that was incorporated into California’s regulations.

This would complement Colorado’s goal of cutting 2005 greenhouse gas emission levels 26 percent by 2025. Vehicles on the road make up the state’s second-largest source of greenhouse gas emissions after electricity generation from power plants, according to the state’s most recent data.

Environmental groups are lauding the executive order as a win for the state at a time when the White House is rolling back environmental protections.

“I think this is a very big moment for the work that is being done in the country on climate policy,” said Jessica Goad, deputy director for the environmental advocacy group Conservation Colorado. “States are going to need to lead the way on this.”

A legal showdown between the Trump administration and California is expected over that state’s decision to set emission requirements that are more stringent than under the Clean Air Act.

Attorney General Cynthia Coffman, a Republican who often has opposed government regulations and is sympathetic to the oil and gas industry, did not return a request for comment on whether Colorado will defend California’s stance.

That call ultimately may fall to whichever attorney general candidate is elected in November. Democrats Joe Salazar and Phil Weiser say they would be willing to defend California’s waiver if challenged by the Trump administration. Republican candidate and 18th Judicial District Attorney George Brauchler did not return a request for comment.

Today’s order requires the Colorado Department of Public Health and Environment to propose a rule that incorporates California’s regulations by August for possible adoption by the end of the year.

Hickenlooper’s executive order said the expected plan by the Environmental Protection Agency to roll back greenhouse gas and fuel efficiency standards could have “serious consequences” for Colorado’s effort to meet its own clean energy goals.

In a statement, he said the executive order was also about protecting Coloradan’s quality of life. 

“Low emissions vehicles are increasingly popular with consumers and are better for our air,” he said. “Every move we make to safeguard our environment is a move in the right direction.”

The auto industry, however, is raising concerns about costs for consumers. Tim Jackson, CEO and president of the Colorado Automobile Dealers Association, said according to most recent reports on car sales, Coloradans drive more trucks than Californians do. That’s one reason why he says it’s crazy to have Colorado’s adhere to California’s emission standards.

“It’s going to be a harder standard for automakers to achieve so they will have to disincentivize, which means raise the price on the vehicles that Coloradans like to drive,” he said. He added that if consumers can’t afford new cars they may keep older, more polluting ones.

According to the American Lung Association, Denver-Aurora ranked 14th out of 227 metropolitan areas for the most polluted cities as measured by the number of high ozone days. A May report by multiple local public health departments in the Denver metro area said vehicle emissions are one to two leading cause for high ozone days. 

Last year, the Colorado Department of Public Health and Environment issued 45 Action Day Alerts, meaning air pollution levels were so high that the agency recommended that people with certain health conditions like asthma stay inside for certain activities such as exercise. There have been 11 such warnings so far this year.

Correction: A previous version of this story stated that the May report was authored by Denver’s Department of Public Health. It was authored by the Metro Denver Partnership for Health, which includes Boulder County Public Health, Denver Public Health and Jefferson County Public Health. 

Traffic congestion on I-25 northbound at 7:00 AM. Photo by John Herrick


  1. “Low emissions vehicles are increasingly popular with consumers and are better for our air.”

    Great! Then let consumers decide to buy them instead of government forcing them to do so.

    Since they’re so popular.

  2. It is hard to believe chickelooper was once a business owner. What a bleeding
    liberal! He cares more for illegals
    than citizens. Want to clean up our
    air? Ban chemtrails

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