How Fast-Growing Colorado is Tackling its Transportation Emissions
From Denver smog to jammed mountain highways, Colorado is focusing on transportation to solve congestion, pollution, and climate problems.
The first in a series of stories based on RMI analysis of how key US states are deploying real climate solutions. See more at State Climate Scorecards.
Denver resident Shalon Bowens grew up in Los Angeles, so she’s no stranger to traffic. But she also grew up riding her bike. Like many Coloradans, she drives an SUV. “I was tired of driving so much,” she says. “I wanted to lose weight, get exercise, and not burn gas.” Now her 2004 Ford Explorer sits in her garage as she rides her electric bicycle to work and around the city. Bowens is a participant in one of the many projects this growing state is implementing to help address transportation-related climate issues.
Over the past decade, people have been flocking to the mountain west, drawn by its legacy of big skies, fresh air, and open roads. From 2000 to 2020, Colorado grew by nearly a third to 5.8 million people, making it one of the fastest growing US states. Yet the rising headcount is driving up congestion, costs, and climate risks, compromising many of the region’s legendary charms.
And bigger problems are looming. Colorado is experiencing firsthand dangerous impacts from climate change including more frequent wildfire, intense drought, and record high temperatures. For long-established locals and newcomers alike, these stresses threaten the health of the region’s people, its ecosystems, and the economy. In the face of these rising threats, the state has set ambitious goals to halve greenhouse gas emissions from 2005 levels by 2030, and to cut them by 90 percent by 2050.
Colorado’s efforts stand out in a scorecard recently released by RMI, a first-of-its-kind assessment of US states’ progress on climate goals. Colorado’s work on transportation — which produces nearly one-quarter of the state’s emissions — offers a blueprint for many fast-growing, western states facing a similar mix of scale and varied challenges. In dense Denver, for instance, urban congestion is growing; yet long road trips define much of the state’s rural reaches.
To tackle this mix of problems, Colorado developed a Greenhouse Gas Pollution Reduction Roadmap, which calls for lowering annual transportation emissions by 12.7 million tons from 2005 levels by 2030. The state’s recently passed $5.4-billion transportation funding bill (SB260) will help reach that goal by putting more electric vehicles (EVs) on the road, enriching biking and walking options, and investing further in a fast-growing mass transit success story linking Denver to more rural areas.
Riding Bustang: A State-Wide Transit System
Mass transit might seem like a tough nut to crack in a state where four-wheel-drive SUVs and pickups rule the roads. Yet Colorado’s statewide transit service, Bustang — a play on the state’s iconic wild mustangs — is proving it can tempt drivers out of their vehicles with the right mix of advantages.
To decrease highway congestion and better connect Denver with communities to the north, south, and west, the Colorado Department of Transportation (CDOT) launched this intercity bus service in 2015. To make the buses convenient and accessible, they’re all equipped with bathrooms and internet, along with wheelchair lifts and bike racks.
Buses may seem like an obvious fix. But financing transit solutions can be notoriously vexing. In 2013, CDOT officials estimated it would cost almost $20 billion to install high-speed rail along the congested I70 corridor that runs 120 miles from Denver to the Eagle/Vail airport. By comparison, the start-up costs of Bustang were only about $10.7 million, it covers a much larger area, and service can be modified more flexibly as demand shifts and grows.
“In the United States, building a mile of subway can be five times as expensive as in Europe. Buses are cheaper to build, buy, and operate,” says RMI Principal Julia Thayne DeMordaunt. “During the COVID-19 pandemic, when many transit agencies made buses free, they were not only a lifeline for frontline workers, they were also a way to stitch together communities across dense downtowns and nearby suburbs.”
Colorado is finding ways to make Bustang’s finances work. When it launched, CDOT required the service to hit 20 percent farebox recovery — the percent of operation costs covered by fares — within several years, or it would be canceled. The national average for farebox recovery in buses is 22 percent. “We hit greater than 50 percent farebox recovery in two years,” says David Krutsinger, former director of transit and rail at CDOT and one of the team members behind Bustang.
In 2015, its first year, Bustang’s service was limited to 13 routes and served just over 100,000 riders. Demand was so high, that by 2019, ridership more than doubled to 251,000 riders. (Although ridership crashed during 2020 and 2021 due to COVID, it’s now making a comeback to near 2019 levels.)
Determining the best routes, stops, and fares took a lot of detailed planning. “We used a combination of demographic data, peer review, ridership trends, historical data, public surveys, and stakeholder feedback — and guessing,” Mike Timlin, CDOT’s manager of mobility operations, explains. CDOT also identified where transit-dependent residents were concentrated and conducted a peer review with other state commuter bus programs to set its fares and optimize its park-and-ride facilities.
Kristin Shannon lives in the western mountain town of Glenwood Springs. As the integration leader for an IT service provider, she travels a lot for work. In the winter, Bustang offers relief from stressful snowy drives, she says. And even in the summer, “I prefer Bustang. The buses have wifi so I can work on my way to and from the airport,” says Shannon.
The service is so popular, that over the past few years CDOT added Bustang Outrider, eight routes that connect rural towns throughout the state, and Snowstang, a service that links Denver to three different ski resorts. There’s also RamsRoute, which operates during the school year between Denver and Colorado State University in Fort Collins. And there’s even a service to shuttle Broncos football fans to Mile High stadium from areas south and north of Denver.
The climate benefits of the Bustang fleet are scaling quickly. Timlin estimates ride switching from cars to the bus network has taken over 100,000 cars off Colorado’s highways, knocking off some 460,000 metric tons of carbon from the state’s annual emissions. More savings will come as the fleet goes electric. “We hope that by 2027, when we start turning over our fleet, we can invest in electric buses,” says Timlin.
City Solutions: Cutting Smog and Boosting Mobility with EVs
Home to nearly 3 million people, Denver is one of the fastest growing and most polluted cities in the country. In the winter, temperature inversions trap dangerous gases coming from vehicle tailpipes and building chimneys, leading to stubborn brown smog that obscures the mountain views and puts the city not far behind Los Angeles on the list of worst cities for air pollution. Electric vehicles are emerging as a way for the city to reduce both tailpipe pollutants and emissions of greenhouse gasses.
In the Montbello neighborhood, the city is running a pilot project to provide free rideshare service to local destinations and to regional transit services using a mix of low-emissions vehicles: an EV, a plug-in hybrid minivan, and a wheelchair-accessible van. Funding for the $500,000 pilot came from a small climate tax the city implemented in 2020 and an increase in city parking meter fees.
One of Denver’s largest neighborhoods, Montbello is a community of color, predominantly home to Black and Latino families. Lacking access to robust public transportation networks, its residents pay above average transportation costs relative to their income.
The on-demand rideshare program has been so successful that it might graduate out of pilot status and continue indefinitely. “We’ve had numerous calls from other neighborhoods interested in having this same type of service,” says Krutsinger, who is now transit director for the city and county of Denver. “So we are definitely looking at expanding to other areas.”
The city also allocated $300,000 of federal CARES Act funding to deploy electric carshare vehicles together with necessary charging infrastructure in six under-resourced communities. Colorado Carshare, which manages the vehicles, is providing subsidized memberships to up to 450 residents of these communities.
Beyond Cars: From Four Wheels to Two
Denver’s ambitions also include getting people out of cars. “We expect the city and county of Denver’s population to grow by 30 percent by 2050,” says Krutsinger. “And the streets aren’t getting any wider. Places thrive more when they have a good balance between auto access and other modes of transportation.”
Electric bikes are leading the city’s diversification charge. In the fall of 2020, the state committed $55,000 toward an e-Bike pilot to increase access to e-Bikes for low-income essential workers. The Can Do Colorado eBike program distributed e-Bikes, locks, and helmets, and provided training for how to safely bike around the city, to low-income Denverites at no cost.
“There’s an awareness at the state and local level of the importance of getting e-Bikes in the hands of folks,” says Jack Todd, director of communications and policy at Bicycle Colorado and the developer of the pilot, “and they’re really starting with low-income populations to do that.”
Bowens was one of the first participants, and she uses her e-Bike to commute to her office at It Takes A Village, a nonprofit organization that works to reduce health and social disparities among people of color. “I normally drive my car to work, but now I ride the e-Bike every day,” she says. “I also use it to run to hospitals to administer COVID tests for my job, to get groceries, and to visit friends.”
“I was glad I was able to be an example to the community. We’re making a difference.”
For Bowens, the shift has been transformative, both physically and financially. She lost 85 pounds since she first got her e-Bike, and is saving about $200 a month on gas. Bowen’s success inspired her mother, sister, and daughter to follow her example — they all bought e-Bikes.
The program is delivering promising emissions reductions, but health gains and cost savings are meaningful too. The National Renewable Energy Laboratory monitored the cyclists and determined that over the first three months of the pilot, the bikers saved some 1,367 lbs. of CO2 emissions.
“Our goal first and foremost was getting people out of single-occupancy vehicles,” says Christian Williss, senior director at the Colorado Energy Office, which funded the pilot. “But we did talk about quality of life and the health benefits that come from riding bikes on a regular basis,” he adds.
For Bowens, the shift has been transformative, both physically and financially. She lost 85 pounds since she first got her e-Bike, and is saving about $200 a month on gas. Bowen’s success inspired her mother, sister, and daughter to follow her example — they all bought e-Bikes. “I was glad I was able to be an example to the community,” she says. “We’re making a difference.”
Building on this success, seven more e-Bike pilots are being implemented across the state, five in rural areas and two more in Denver, all geared toward low-income essential workers. “We know there’s huge opportunity for e-Bikes in Denver and beyond,” says Todd.
Great Progress but More Work to do
In December 2021, the state also passed a standard that requires CDOT and regional planning agencies to set GHG reduction targets. If they don’t reach their targets, they are required to develop a GHG Mitigation Action Plan and shift more funding toward clean transportation projects. Matt Frommer, senior transportation associate of Southwest Energy Efficiency Project, calls this work a gamechanger for the state.
Most state departments of transportation continue to invest in highway expansions in the name of congestion relief. “But we can’t build ourselves out of congestion and it doesn’t achieve any of our other social or environmental goals,” Frommer says. “With this standard, DOTs across the state will have to invest in more sustainable options.”
Even so, Colorado has substantial work to do. According to RMI’s Colorado state scorecard, with current policies the state’s 2030 transportation sector emissions will be 29 percent below 2005 levels — less than the 40 percent goal. Significant investments as well as effective implementation are required to meet state targets and unlock the full benefits of climate action.
For Frommer, Colorado is headed in the right direction. “We could either use [federal stimulus funding] to dig the climate hole deeper with wider highways that bring more vehicles and all the emissions that come with them,” he says. “Or we can use it to build out connected multimodal transportation system with transit, biking, walking, and transit-oriented development.”
In fact, Colorado’s next moves could help advance some of the most important climate policies in the country, all while delivering economic opportunity, improving public health, and creating a safer, more resilient future.A passenger waits to board Bustang (top), passengers using the free Montbello Connector EV (middle and bottom).