RTD directors for years have prioritized converting metro Denver’s aging fleet of 995 diesel-powered buses to cleaner, quieter battery-electric vehicles, in line with Colorado’s climate goals.
But agency officials are buying new diesel buses instead — and planning to borrow $539 million for diesel bus purchases over the next five years, according to documents reviewed by The Denver Post.
It marks a behind-the-scenes change of direction reflecting an increasingly complicated landscape for public transit. The Regional Transportation District has long been a leader, pioneering the introduction of modern buses intended to reduce pollution.
The problem is that RTD’s current diesel buses “need to be replaced at the end of their useful life” and “this may or may not coincide with the availability of the charging facilities” and electric buses, RTD Chief Executive and General Manager Debra Johnson told the Post in an emailed response to questions. She did not consent to answer questions in person.
Johnson blamed “the impact of tariffs on the supply chain, scarcity of original equipment manufacturers, Buy America/Build America restrictions, and lack of availability of low- or zero-emission vehicles.”
The plan to buy diesel buses – contained in a financial document and an email sent to RTD’s elected directors this month — would delay a transition to electric buses celebrated on RTD’s website. It could lock RTD into diesel transit for at least another decade across the agency’s 2,342 square-mile service area because transit agencies typically run buses 12 years or 500,000 miles, whichever comes first.
The shift began in May when RTD’s directors approved a $51 million transfer of funds to purchase 47 new buses for Denver’s East Colfax Avenue rapid transit lane in 2027 that will burn diesel, contrary to initial staff assurances that these would be hybrids, agency emails show.
Public transit agencies in other U.S. cities are converting their fleets to electric and hybrid buses. Some bought 60-foot electric-hybrid buses made by the U.S. company New Flyer, which no longer produces them. The RTD’s target date for completing its shift by 2050 ranked behind the targets in Los Angeles (2030), Seattle (2035), Chicago (2040), and New York (2040).
Metro Denver isn’t giving up on the goal, Johnson said. “RTD remains committed to the acquisition of low- and zero-emission vehicles, predicated on funding availability, board approval, vehicle availability, adequate workforce, provision of modified and new facilities that accommodate those vehicles, Federal Transit Administration fleet replacement policies, current spare ratios, and fleet replacement schedules,” she said.
RTD directors haven’t decided whether to approve borrowing $539 million for the diesel buses, which would add to the agency’s current $2.7 billion debt from past projects. Sales taxes paid by residents of eight metro Denver counties fund 70% of the RTD’s $1.2 billion annual budget.
“We have limited debt capacity, for sure,” RTD first vice-chair director Patrick O’Keefe said.
If RTD executives want to reverse the shift from diesel to electric buses, “I don’t think our board members will support that,” O’Keefe said, advocating a full discussion of the issue before approving any plan.
When RTD executives asked directors in May to approve the funds transfer to buy 47 buses for the Colfax BRT system, Johnson told the directors these would be “hybrid diesel” buses, agency records show.
This week, RTD communications staffers said those BRT buses will be “clean diesel.”
That was news to RTD director Chris Nicholson.
“We approved those buses a couple of months ago for BRT as hybrids. It came to us as: ‘We’re going to buy hybrids.’ We approved hybrids. ‘Clean diesel’ is just a bus with a very efficient diesel engine. A hybrid is a bus with a battery,” Nicholson said.
“If the agency is now saying we are not buying hybrids, that’s a big deal. It means we are moving backward. What is our commitment as a board to making this transition? It is very clear to me that voters care a great deal about seeing us make this transition aggressively. So why would we be borrowing $539 million to buy more diesel buses when we haven’t spent anything yet for the transition to electric? I mean, we have a plan. But where is the beef?”
He and other directors last week delayed a scheduled vote on whether to approve the financial forecast document that contains the plan for borrowing $539 million to buy diesel buses.
Running electric buses instead of diesel on Denver’s new Colfax rapid transit lane would be difficult, Johnson told Nicholson in an email Thursday, because Denver designed the system to use 60-foot buses, and New Flyer, the Buy America-compliant company that made those, ceased production. New Flyer makes 40-foot electric buses, she said, but buying enough of those would cost more overall and require running buses at a greater frequency than Denver wants, she said.
“If RTD were to buy 60-foot diesel-electric hybrid buses to operate on the Colfax BRT, it would almost certainly have to use 100% local funds to purchase vehicles from Europe or Asia, and these would be subject to newly imposed tariffs.”
The RTD bus fleet transition plan unveiled in December prioritizes setting up charging facilities and declares that the RTD will acquire nearly 300 diesel hybrid electric buses by 2030 and 75 battery-electric buses by 2035 – toward the target for ensuring zero greenhouse gas emissions no later than 2050. Back in 2023, directors had to bail out of an $18 million contract to buy 17 electric buses due to a lack of charging facilities — a problem they resolved to prevent in the future.
The plan estimates fleet transition costs through 2035 at $600 million.
For years, RTD has run cleaner methane-powered hybrid and electric buses on Denver’s 16th Street Mall. But the bulk of RTD’s 995 buses burn diesel.
RTD officials did not provide the average age of those buses.
The fleet transition plan “will be implemented in future years if and when the board approves appropriation of funds in those future years,” Johnson said.
RTD officials in recent years declined to compete for Volkswagen legal settlement money and state grants available for buying electric buses, said Danny Katz, director of the Colorado Public Interest Research Group, which advocates for better public transportation and a healthy environment. RTD “could have been more aggressive” in setting up charging facilities as a first step, Katz said.
“To the extent we would be borrowing dollars for buses, couldn’t there also be dollars in there for upgrading facilities for charging electric buses? There’s an urgency to move to more electric buses,” he said.
“Tailpipe emissions from buses are a small piece of overall emissions, and buses themselves are a tool to reduce vehicle emissions if people leave their cars at home and ride buses. But we also want to make our buses electric. Diesel buses are noisy and polluting. ….. Let’s make sure our buses are electric so that we can cut the noise and the pollution.”