A Maryland toll lanes proposal placed on life support last month got a second wind Wednesday when D.C.-area leaders reversed an earlier vote, reviving Gov. Larry Hogan’s signature transportation project.

The Transportation Planning Board’s 28-to-10 vote in favor of widening Interstate 270 and part of the Capital Beltway with toll lanes marked a major victory for Hogan’s traffic-relief plan. The governor’s proposal to build billions of dollars worth of toll lanes via a public-private partnership suffered an unexpected blow June 16, when the board removed it from a required air-quality analysis at the behest of some Montgomery County leaders.

Hogan (R) gained some support from Montgomery leaders Tuesday after agreeing to include state funding to design bus lanes as part of the highway expansions. Potential projects include a long-planned Corridor Cities Transitway between the Shady Grove Metro station and the Metropolitan Grove MARC commuter rail station, or express bus lanes along Rockville Pike (Route 355) between the Shady Grove Metro station and Clarksburg.

Directing money to bus projects, some Montgomery officials said, was the kind of significant transit investment they had been seeking since Hogan first announced the plan in 2017.

The Maryland Department of Transportation has committed at least $60 million to design a bus project in Montgomery, according to planning board documents. The money would come from $145 million the state expects to receive as an upfront payment from a private team chosen to build the lanes. That funding would be in addition to $300 million the private team previously promised for transit projects as part of the toll lanes construction.

In a statement, Hogan called the vote “a great victory for the Marylanders sick and tired of being stuck in soul-crushing traffic.”

It was also a “win,” the governor said, “against the small group of Montgomery County politicians and far-left activists” who continued to oppose the highway expansion as too environmentally destructive, even with the additional transit funding.

Toll lane opponents said they will focus next on the state’s Board of Public Works, which is expected to vote in the next several weeks on the first $50 million contract to develop the lanes’ design. The state also faces a potential lawsuit from a losing bidder that has alleged the winning predevelopment proposal was based on unrealistically low construction cost assumptions.

The planning board’s approval was significant because D.C.-area projects must undergo an air-quality analysis to be included in the region’s long-term transportation plan, which is a requirement for federal environmental approval. The board’s removal of the toll lanes proposal from that analysis last month threw the project into doubt as MDOT prepares to seek approval of the first contract.

The new support from a majority of the Montgomery County Council appeared to sway some regional planning board members who previously had rejected the toll lanes.

Arlington County Board member Christian Dorsey (D) said the greater commitment to mass transit showed that MDOT “has made significant improvements, in my mind.” He said he would have preferred a regional consensus among Maryland leaders, but that didn’t appear to be possible.

“I want to reward progress,” Dorsey said.

Other board members said the Maryland highway expansion would help the entire region by relieving Beltway bottlenecks at the American Legion Bridge and creating a network of express lanes that buses could use to provide faster, more reliable service.

Northern Virginia has more than 60 miles of toll lanes and is building or planning another 36 miles, including extending its Beltway lanes north toward the American Legion Bridge at the Maryland border.

“Our economic future depends on good transportation,” said Virginia Sen. Dave Marsden (D-Fairfax).

But some Montgomery officials said the governor’s plan, even with more money for bus lanes, would exacerbate climate change and, by relying on private financing, result in toll prices that many Marylanders couldn’t afford.

“This was never about the Corridor Cities Transitway and never about holding up the state for [transit] money,” Montgomery County Executive Marc Elrich (D) told the board before voting against the highway expansion. “This is about more fundamental questions about the project.”

Elrich also criticized the Hogan administration for threatening to cut $1.23 billion worth of road and transit projects if the toll lanes proposal failed. While MDOT officials said those cuts would be necessary to offset private financing that would be lost, Elrich said the governor was “trying to strong-arm” local officials to win votes.

Prince George’s officials, who had previously expressed concern about MDOT’s proposed cuts, reversed their opposition from June. Representatives for County Executive Angela D. Alsobrooks (D) and the county council voted to restore the toll lanes.

Several Northern Virginia officials, as well as the District’s transportation and planning agencies, also changedtheir votes from last month.

An expectation that the vote would be close on a project valued at $6 billion prompted the entire board to weigh in — the highest meeting attendance in 20 years, said Lyn Erickson, a staffer for the Metropolitan Washington Council of Governments, the planning board’s umbrella organization.

The board received an unusually large number of public comments on the project — 293 seeking to restore the toll lanes and 270 urging the board to nix them again, Erickson said.

Under Hogan’s plan, both I-270 and the western part of the Beltway would get four toll lanes — two in each direction. They would start on the Virginia side of the American Legion Bridge to the I-270 spur, then continue to Frederick. The first section to be built on I-270 would end around I-370. The state has just begun the environmental study for I-270 north of I-370, where construction would follow.

The regular lanes would be rebuilt and remain free.

The project also would include replacing and expanding the nearly 60-year-old American Legion Bridge, which has broad political support in Maryland and Virginia.

MDOT has selected Australian firms Transurban and Macquarie to develop the lanes’ design over about a year while negotiating a 50-year deal for the companies to build them and finance the construction in exchange for keeping most of the toll revenue. However, under the “predevelopment” contract, MDOT would have to reimburse the companies up to $50 million if the project doesn’t clinch federal environmental approval — a risk that some opponents said was too great for the state to take on until the planning board signed off.