CDOT takes an important nation-leading step forward with its greenhouse gas rule

With its greenhouse gas reduction rule in place, Colorado’s Department of Transportation (CDOT) becomes one of the leading states in tackling the single biggest source of climate pollution - the transportation sector. Success will be determined by how well it is implemented. The next six months will be critical.

I-25 traffic - credit staff

Transportation is the single-biggest source of greenhouse gas emissions in Colorado because nearly all our vehicles are gas or diesel-powered. 

And while our state is aggressively implementing policies and investing hundreds of millions in transitioning our vehicles to cleaner, electric-powered ones, that transition won’t happen fast enough. 

The most ambitious projections anticipate about 20% of the vehicle fleet will be electric by 2030.

According to the Governor’s Greenhouse Gas Pollution Reduction Roadmap, that means electric vehicle strategies will only get us about 60-70% of the way to where we need to go.  

We need to also cut transportation pollution by expanding the number of trips that are completed without a car. 

That’s why today’s decision by the Colorado Department of Transportation to set a goal for reducing greenhouse gas emissions and create a set of strategies to meet that goal by expanding travel options is a huge deal. 

Looking across the country, Colorado is a national leader and is one of only a few state DOTs that even has a goal like this. 


The goal: Cut 1.5 million metric tons of pollution

The heart of CDOT’s new rule is a goal to cut greenhouse gas emissions by 1.5 million metric tons (MMT) by 2030, focusing on strategies that will reduce the need to drive to complete every trip. 

A cut of 1.5 MMT is significant and ambitious. It would get Colorado about half of the needed reductions outside of electrification (see image above). 

It’s a floor not a ceiling, which is really important because, done right, this rule should result in even bigger reductions. It needs to. 

The other key piece to this rule is that it applies to Metropolitan Planning Organizations (MPOs). 

Our transportation system has many levels of decision makers. While CDOT has responsibility for a huge part of our roads, bridges, and transit systems, local governments and regional bodies, like MPOs, oversee and operate the rest. 

Two MPOs – the Denver Regional Council of Governments (DRCOG) and the North Front Range MPO, which covers parts of Larimer and Weld County – will also need to implement this rule immediately with the rest of the MPOs joining at later dates. 

This is important because many of the decisions surrounding our transportation system are made on a local level and, if we’re going to reduce climate pollution, we need our local and state governments to be pulling in the same direction. 

For example, we can’t have one governing body working to make their main streets more pedestrian friendly and reducing the amount of driving while another is erasing that pollution reduction with wider roads that pull more people into cars. 

Pedestrian-oriented main street in Arvada – credit staff


Pollution reduction tools and prioritizing cleaner transportation options

To cut pollution in the transportation sector we need to give people the ability to drive less and live more. 

The main way you measure that is by Vehicle Miles Traveled (VMT). As people gain real travel options, more trips can be completed without having to drive. 

Less driving = less VMT = less pollution.  

Everyone needs travel options so we don’t have to complete every trip by car, whether it’s to work, school, a grocery store, a doctor or a park.  

Right now, most people don’t have real travel options. 

We need buses and trains that come every 5-10 minutes, are fast and reliable, and take you where you want to go. 

RTD bus in Denver – credit staff

We need safe, protected bike lanes, sidewalks and infrastructure that ensures crossing the street is comfortable, not life-threatening. 

It would also help if communities were built in ways that support people walking and biking instead of forcing people to drive because there is nothing close by to walk or bike to. 

Kids walking to school under I-70 viaduct – credit staff

Implemented well, CDOT’s rule will shift our investments in ways that expand travel options by developing a set of pollution reduction strategies for CDOT, local governments and MPOs to use.

CDOT’s rule envisions a number of strong pollution reduction strategies including:

  • Adding transit in ways that can replace a trip in a car
  • Improving pedestrian and bike access in ways that allow people to reduce car trips or access transit
  • Encouraging land use that better aligns with walking, biking and transit
  • Improving the safety around crosswalks
  • Adding multi-use trails
  • Supporting transit by providing first and last mile connections to stations and stops
  • Electrification of loading docks and the large commercial trucks that access them

Most of the strategies focus on expanding options that allow people to live their lives without driving to do everything. 

Now that the rule is adopted, CDOT will develop the details and guidance around these strategies through a planning process this winter. 

The guidance for how to meet this rule is critical because we won’t know the exact greenhouse gas reductions from what we build or operate until after it’s built and launched. 

So to ensure we build the right stuff that actually reduces pollution, we need to make some assumptions. 

Those assumptions (how much pollution will be reduced by a new bus line vs. a new crosswalk vs. a roundabout) will be developed over the next few months and we will need to watchdog the process. 

Some measures, like roundabouts, may serve a safety function but may not be an effective climate strategy especially if they wind up increasing the amount of driving.   

At the same time, CDOT is also realigning what projects they will fund in the next few years as part of their 10-year plan.

You may have heard – there is a lot of new money coming to our transportation system after the federal infrastructure bill and the state passed SB21-260

To meet our climate goals, we’ll need to prioritize the right transportation projects and strategies. 

I believe this step is even more important than the development and adoption of the rule. And it’s already started. 

It is critical people engage with their local governments, which are the ones who have the biggest impact on what will be prioritized, built and operated in a given city or region. 


Cutting greenhouse gas emissions with better travel options brings huge benefits

This rule is about cutting greenhouse gas emissions – a lot of greenhouse gas emissions. 

In a supporting document for this rule, CDOT presented a scenario for how the rule could be met. According to CDOT, greenhouse gas emissions could be cut by 1.5 MMT by 2030 by: 

  • Expanding transit service 70% by 2030 and cutting fares by 50%.
  • Adding 1,900 miles of new sidewalks and 5,000 miles of new bike lanes (ideally focused in ways that link to transit or create networks of walking and biking).
  • Focusing new housing and jobs in existing communities so people can live closer to where they work and play.

The strategies above will bring benefits way beyond greenhouse gas emission reductions. 

When we cut climate pollution by reducing the need to drive, we’re also reducing other air pollutants, especially the stuff that fuels the ozone that we were choking on this summer.  

Ozone haze in Jefferson County during the summer of 2021 – credit staff

It’s great that one solution, providing more travel options, can tackle both climate change and ozone pollution at the same time. But wait…there’s more. 

Expanding sidewalks and bike lanes recruits people to walk and bike because it is safer. That safety investment will help save lives at a time when cities like Denver are seeing a record number of fatalities on our roads. 

In addition, the more options, the less need to drive or even own a car to begin with. According to CDOT’s analysis, “households within 1/2 mile of transit stations own on average 0.9 cars, while households in the rest of the metropolitan regions own, on average, 1.6 vehicles.”

As our decision makers grapple with the high costs of living in Colorado, helping people avoid owning a car could save them thousands of dollars. 


Replacing a few trips makes a big difference

For the majority of Coloradans that spend hours stuck in their cars every week this rule results in more options. 

Enough good options means less trips by car.

Done right, CDOT estimates that a 1.5 MMT cut in greenhouse gas emissions through transit, walking, biking and land use decisions would result in a cut in VMT per capita by 7%. 

That means, on average, we each would drive 7% less miles a year.

For me, a 7% cut in driving is a few trips. Instead of driving a mile to grab some eggs, I’d hop on my bike. Instead of driving to the Broncos or Rockies game, I’d hop on a bus. 

Not everyone will do that. But reprioritizing our next few years of investments so everyone can do it, will recruit an awful lot of people to do it. 

This rule won’t result in these investments automatically. So I offer three suggestions:

  • Stop for a second and celebrate that Colorado’s DOT is leading the country by having a greenhouse emissions reduction goal. That’s a big deal.
  • Roll up your sleeves and join me in making sure the rule is implemented in a way that leads to a significant expansion of clean travel options for everyone. 
  • Ensure CDOT and others evaluate every investment afterwards so we know if what we’re actually building and operating is resulting in options that recruit people away from always driving.

The next decisions will be driven by local governments and regional MPOs as much as CDOT. 

Let’s raise our voice and win the transformation of our transportation system that we all deserve. 


Danny Katz

Executive Director, CoPIRG

Danny has been the director of CoPIRG for over a decade. Danny co-authored a groundbreaking report on the state’s transit, walking and biking needs and is a co-author of the annual “State of Recycling” report. He also helped write a 2016 Denver initiative to create a public matching campaign finance program and led the early effort to eliminate predatory payday loans in Colorado. Danny serves on the Colorado Department of Transportation's (CDOT) Efficiency and Accountability Committee, CDOT's Transit and Rail Advisory Committee, RTD's Reimagine Advisory Committee, the Denver Moves Everyone Think Tank, and the I-70 Collaborative Effort. Danny lobbies federal, state and local elected officials on transportation electrification, multimodal transportation, zero waste, consumer protection and public health issues. He appears frequently in local media outlets and is active in a number of coalitions. He resides in Denver with his family, where he enjoys biking and skiing, the neighborhood food scene and raising chickens.