Maryland Gov. Larry Hogan (R) has said the state can expand the Capital Beltway and Interstate 270 at no net cost to taxpayers because the private sector will build billions of dollars of toll lanes in exchange for keeping most of the revenue.

But that promise doesn’t appear to include the potential public expense laid bare by a similar public-private partnership on the state’s troubled Purple Line project: those stemming from a legal challenge that can stall construction, drive up costs and sour relationships underlying decades-long contracts. Before quitting in September, the Purple Line’s construction contractor blamed lawsuit-related delays for $131 million in cost overruns.

The potential for a legal fight over Maryland’s highway plan grew more apparent this month, when environmental groups, local officials and project critics responded to the state’s draft environmental impact statement. Legal experts say opponents typically lay their legal groundwork in their comments because doing so is a prerequisite for filing a lawsuit later.

“There’s no doubt in my mind this project is headed to federal court,” said Gus Bauman, a veteran land-use lawyer for Beveridge & Diamond. Bauman represented the Maryland Department of Transportation in two 2006 lawsuits filed by several environmental groups against construction of the Intercounty Connector toll road.

The Sierra Club’s Maryland chapter said it plans to sue if the state doesn’t address its concerns with the environmental analysis. In 207 pages of comments, the Sierra Club and about 50 other environmental and civic groups said the state hasn’t adequately assessed the highway widening’s effects on parkland, air and water quality, and historical sites, among other problems.

“If the agencies decide to move forward, and the flaws are not addressed, we anticipate challenging that decision,” said Josh Tulkin, director of the Maryland Sierra Club.

The Maryland-National Capital Park and Planning Commission, the planning body for Montgomery and Prince George’s counties, has objected to the idea of widening the Beltway through its public parkland. It submitted 82 pages of comments and detailed questions on letterhead for Akin Gump, a prominent law firm.

The commission cited the state’s “failure to consider reasonable alternatives with fewer impacts to the environment,” such as expanding transit or diverting traffic to the Intercounty Connector.

General counsel Adrian R. Gardner said the commission is “engaged in good faith discussion with the state about mediating some issues raised” in the environmental analysis. He downplayed the significance of the law firm’s involvement, saying the commission often hires outside lawyers for federal expertise.

The two counties, Gardner wrote, “deserve nothing less than an experienced legal team that is prepared to handle every potential outcome.”

But some legal observers said the commission sent a clear message with the law firm letterhead.

“If Park and Planning has their comments filed by Akin Gump, and not their general counsel’s office, that in and of itself is quite revealing,” said Bauman, the commission’s former legal counsel and chairman.

The proposal recently has drawn powerful objections, even without threats of a lawsuit.

Comments from the Montgomery and Prince George’s county governments cited what they said were numerous shortcomings in the environmental review.

The U.S. Navy reminded MDOT that it had said “multiple” times it will not provide property along the Beltway near Walter Reed National Military Medical Center in Bethesda because of anti-terrorism requirements. The state’s analysis of how construction would affect the base’s “mission critical infrastructure,” the Navy wrote, was “woefully inadequate.”

MDOT also had given short shrift to commuting changes caused by the pandemic, the Navy said.

MDOT declined to make anyone available for an interview about the study, the project’s opposition or the potential for a legal challenge.

In response to emailed questions, project spokesman Terry Owens wrote that MDOT and the Federal Highway Administration received nearly 3,000 comments representing “a broad spectrum” of opinions.

He said the two-year study “fully complied with federal laws and regulations” by doing an “extensive analysis” of the proposed toll lanes and “reasonable alternatives” in nearly 18,000 pages of technical reports.

“MDOT cannot comment on legal proceedings,” Owens wrote, “whether ongoing or those that may occur in the future.”

He said MDOT is “planning measures to address litigation risks” in case of a lawsuit.

In a Nov. 20 legislative hearing on his agency’s proposed budget, Maryland Transportation Secretary Greg Slater said MDOT will examine the public comments to see how they might be addressed.

While the Navy’s objections are “pretty significant and serious,” Slater said, “we want to work through that with them.”

In public-private partnerships, experts say, the government typically assumes the risk — and the costs that come with it — of a project obtaining, and keeping, federal environmental approval. That approval is typically the point of attack for lawsuits.

As the 16-mile Purple Line project has shown, entering a decades-long public-private partnership amid a looming legal challenge poses a potentially costly risk to the state.

MDOT’s 2016 signing of the $5.6 billion Purple Line partnership amid a pending lawsuit backfired when a judge suspended the federal approval. The ruling postponed the start of light-rail construction by 10 months — a delay the contractor later said added $131 million in cost overruns.

That early holdup became the first in a series of construction delays that ultimately led the private team to terminate the 36-year contract. While the lawsuit-related delays appeared unrelated to the subsequent problems, they pitted the state and the concessionaire against each other over the construction schedule and costs.

The ensuing three years of cost disputes, which wound up in court, ended Tuesday, when MDOT announced it had agreed to pay $250 million more to resolve the cost claims and salvage the Purple Line partnership.

Owens said the state will collaborate with companies on the toll lanes earlier than it did on the Purple Line. MDOT plans to enter a “predevelopment agreement” with a private team this spring, after the final environmental study is expected to be approved. The companies will meet with adjacent communities, property owners and the public in hopes of reducing the impacts in the design of the toll lanes, Owens said.

Such a “progressive” process, Owens said, “reduces risks and mitigates cost and schedule issues that may be present if a lawsuit is filed.”

MDOT plans to seek approval from the state’s Board of Public Works for the first 50-year toll lane contract in summer 2022, at the earliest, Owens said.

Because environmental lawsuits typically take up to two or three years to play out on appeal, legal experts say, MDOT could end up committing to a decades-long contract worth billions amid a pending legal challenge.

DJ Gribbin, founder of Madrus, a Leesburg-based infrastructure consulting firm for governments and companies, said Maryland’s rocky Purple Line partnership is “perceived as a bit of a cautionary tale” in the industry.

Even so, he said, it’s not unusual for states to pursue projects under threat of legal action.

“You don’t want every project in your capital plan delayed by six months in case you get a lawsuit that takes a year-plus to get a judgment,” said Gribbin, a former special assistant to President Trump on infrastructure issues. “I don’t think taxpayers would want governments to delay every project by years to quantify the litigation risk.”

Because lawsuits are anticipated on controversial projects, state lawyers typically work closely on major environmental reviews to ensure they will pass muster in court, experts said. During the Intercounty Connector study, Bauman said, he spent four to five months with other lawyers and state and federal agencies scrutinizing the “purpose and need” statement, which was about a page long.

Jonathan Gifford, a professor and expert in public-private partnerships at George Mason University, said state transportation officials might proceed with a controversial project if their lawyers conclude that any lawsuits are unlikely to succeed or cause significant delays.

The companies — and, more importantly, their investors — will protect themselves from a legally vulnerable environmental analysis, he said. That’s because private financing relies on collecting toll revenue to pay back bondholders and other investors on a certain schedule.

“I’d be astonished if the state or any developer would enter into an agreement without having very explicit discussions and agreeing on how they’d cover such an eventuality,” Gifford said.

Emmet Tydings, a toll lanes supporter and longtime member of the Citizens Advisory Committee for the region’s Transportation Planning Board, said he expects the Sierra Club or other opponents to fight the highway project in court.

“The environmental groups’ basic mantra is, ‘No more pavement,’ ” Tydings said.

He said adding toll lanes is the only way to relieve crippling traffic congestion. Opponents’ arguments that the state hasn’t sufficiently studied less environmentally harmful options, such as expanding mass transit, are a “Trojan horse” designed to try to kill the proposal, he said.

If a legal challenge ends up costing taxpayers by delaying the toll lanes’ construction, Tydings said, “I put that on the Sierra Club or those that sue.”