The Regional Transportation District plans to add nearly 300 diesel hybrid electric buses by 2030 and 75 battery-electric buses by 2035.
The agency’s new fleet transition plan published this month plots out a path toward RTD’s target of achieving net zero greenhouse gas emissions by 2050. Its board adopted that goal in May 2023, and at the same meeting terminated a contract to buy 17 battery-electric buses because it didn’t have the necessary infrastructure to charge and store them.
“We realized that our facility was not in a state to accept, safely operate, and maintain those vehicles,” said Charlie Stanfield, a planning project manager at RTD. “We let the vehicle get ahead of the facility."
The new, “facilities first” plan aims to avoid another such situation. It comprehensively examines needs for facility upgrades, staffing and training needs, and system-wide costs.
While RTD has had some cleaner buses in its fleet for decades — first the hybrid electric and then battery-powered 16th Street Mall shuttles — the vast majority are traditional diesel vehicles.
The first phase of the plan estimates that the shift away from diesel and toward pricier hybrids and battery-powered buses, along with facility upgrades, will cost RTD an extra $600 million over the status quo through 2035. It’s not yet clear how the agency will cover the premium.
The second phase, which looks beyond 2035, is murkier, but RTD staff hope it will clear up as technologies improve and, hopefully, prices fall. The agency estimates that a full transition of its fleet to zero-emission vehicles, which could be battery-powered, hydrogen-powered, or some combination of the two, would cost billions of dollars.
“The plan is very expensive,” Stanfield said.
RTD expects its facilities and buses will generate just over 140,000 tons of carbon dioxide in 2025. Its near-term plan would reduce that to under 120,000 tons, or about a 9 percent drop, by 2035.
RTD’s plan is pricey, but not particularly ambitious compared to its peers.
Thirteen of the 25 largest U.S. public transit agencies have established mandates to convert their entire bus fleets to zero-emission vehicles, according to a March 2024 white paper from consulting firm WSP.
The most common target year is 2040, adopted by transit agencies in New York, New Jersey, Chicago, Philadelphia, Boston, Oakland and Phoenix. Agencies in Seattle and San Francisco are shooting for 2035. King County Metro in Seattle says it purchased its last hybrid buses in 2023 and that it will only purchase battery-electric buses in the future.
The WSP report indicates that RTD’s 2050 goal is the latest among its peers that have set one.
Some transit agencies have struggled to meet their goals though, citing rising costs and other problems. Some transit experts and advocates note that public transit buses account for a tiny fraction of total transportation-related emissions, and argue that a more effective way to reduce pollution would be to add more transit service to help reduce car trips.
With the limited range in today’s electric buses, RTD would likely have to add even more costly vehicles and staff to match its diesel fleet’s capabilities if it were to go all-electric. That added cost would be counterproductive, Stanfield said.
“If we're sacrificing our service delivery for a fleet technology, we're not going in the right direction,” he said.
But transit agencies should be able to both improve service and shift to electric, said Matt Frommer, transportation and land use policy manager at the Southwest Energy Efficiency Project, an environmental research and advocacy organization.
He said RTD has failed so far to successfully use state and federal grant money available for fleet electrification that’s been available for years. Frommer also said the transition plan “lacks ambition.”
“It's encouraging to see a plan,” he said. “But I don't think it goes far enough, and I think it relies too much on diesel and hybrid vehicles and not enough on all-electric vehicles that really deliver on climate and air quality.”
In the late 2010s, RTD boasted the largest battery electric bus fleet in the country — 36 vehicles that roll up and down the 16th Street Mall. But RTD’s efforts in that space have stalled since then, Frommer said. Its new plan calls for the next purchase of battery-electric buses to be in 2030 — 15 years after its last successful electric bus order in 2015.
“It’s disappointing that they have not even piloted any of the newer electric buses,” Frommer said, comparing RTD’s aging 16th Street Mall fleet to the first iPhone.
Initially, RTD board members were leaning toward a more aggressive zero-emission target date of 2038. But that shifted as the directors spoke with industry officials at peer agencies around the country and RTD’s own staff, who cautioned that moving toward zero-emission vehicles will be expensive and complicated.
“While it'd be great to see it happen earlier, I think the timeline they laid out looks to be an appropriate balance of taxpayer dollars and expenditures,” said former RTD board member Bobby Dishell, who led the zero-emission policy discussions for the board.
RTD also needs to figure out how to pay for the transition.
Even if it were successful in reeling in federal and state grant money for cleaner buses, RTD says those won’t fully cover all of its elevated costs through 2035. The agency anticipates it will have to come up with at least $361 million to help fund the near-term transition plan, and financing costs would push that even higher.
The amount of federal funding available could change under a new Congress and the second Trump administration, RTD’s plan says.
“We plan to access that as much as we can,” Stanfield said. “But the reality is that we're not going to be able to, at least in this current environment, fully pay for the transition.”
The board will have to decide how to cover the extra expenses, Stanfield said. But the transition plan implies that RTD does not want to free up cash by cutting service.
“RTD’s primary focus is to continue delivering transit service to meet the region's needs,” it reads.
