Potholes are such a problem on the Baltimore-Washington Parkway that officials have lowered the speed limit. (Astrid Riecken/For The Washington Post)

For the thousands of drivers who have barely managed to avoid being swallowed by one of the potholes on the Baltimore-Washington Parkway, their commute has entered another circle of hell.

The National Park Service decided the potholes present such a danger to motorists that it lowered the highway’s posted speed limit to 40 mph from 55 along one stretch.

The lower speed is in effect between Routes 197 and 32.

“Lowering your speed will make it safer for you and for the crews working every day to address current road conditions,” Park Service Superintendent Matt Carroll said in announcing the change earlier this month.

Potholes appear to have hit the Washington region especially hard this year with the dramatic temperature swings and repeated freezing and thawing creating perfect conditions for the craters to multiply.

So, a curious driver might ask, why not just fix the potholes instead of lowering the speed limit on a road that carries 125,000 cars daily?

The 29-mile parkway is one of the busiest thoroughfares in the region for commuting between Washington and Baltimore, and it connects to several major job centers, including NASA’s Goddard Space Flight Center, the National Security Agency at Fort Meade and Baltimore-Washington International Marshall Airport.

“If you are saying you have to slow down the speed limit in order to ensure the safety of drivers, okay, we get it, safety first, you can’t be mad at that. But please do something to fix the roadway,” said D.C. resident Bashon Mann, a Navy lieutenant commander stationed at Fort Meade.

The Park Service, which owns about 19 miles of the roadway from the District line to Fort Meade, said crews used more than 60 tons of asphalt to patch potholes in February and continue to work there daily as the weather allows. But the road has continued to deteriorate, the agency said, leaving no choice but to lower the speed limit.

What the parkway really needs, officials say, is a complete overhaul.

The Baltimore-Washington Parkway has long shown signs of wear and tear. A need to resurface the road was identified a decade ago, but repaving has been done only in segments as funding has become available, Park Service officials said.

“To put this in larger context,” Park Service spokeswoman Jenny Anzelmo-Sarles said, “the NPS has a maintenance backlog of about $11.6 billion, half of which is related to transportation infrastructure.”

The maintenance of roads, buildings and other facilities across the national park system has been postponed for years because of budget constraints. Aging infrastructure and years of inconsistent federal funding have contributed to that backlog.

The Park Service gets funding for maintaining its transportation assets through the U.S. Department of Transportation and that agency’s operations and construction appropriations. But Park Service officials say they cannot rely on appropriated dollars alone to address the backlog and are looking at other options.

Tires and rims damaged by potholes are piled up at Mac’s Tire Service on Florida Avenue NE in Washington. (Astrid Riecken/For The Washington Post)

The section of parkway that is in the worst shape and where the speeds were lowered is expected to undergo a major repaving starting in the fall. It would be the first complete repaving of the parkway in 20 years. It’s unclear how much the repaving would cost because the project must go through a bid process.

Officials say improvements have already been made from the District line to the Patuxent River Bridge near the Maryland 197 interchange. The final phase of that project is scheduled for completion in 2021.

“We are currently investigating more immediate solutions while working with the Federal Highway Administration to try and expedite the start of this phase of the repaving project,” Anzelmo-Sarles said. But the work can’t be done as long as temperatures continue to drop below freezing because repaving requires warmer temperatures or the work won’t last, she said.

Those who use the road daily say they have never seen it so bad. Mann, who commutes 25 miles to Fort Meade from his home in Southeast Washington, said he sees drivers pulling over with flat tires and damaged rims almost daily. He has been lucky so far.

The stretch of the highway just south of Maryland 198, both north and southbound, has seen the worst of it. Signs are posted warning drivers of a “Rough Road” ahead and the lowered speed limits near Fort Meade.

But even before the signs were up, drivers had taken to social media to complain about their trips, calling the scenic parkway “hell on earth,” “a hot mess” and “downright dangerous.”

One driver tweeted jokingly that he saw a “4br 2 bath pothole” on the parkway.

Mann tweeted at Maryland Gov. Larry Hogan (R) on Feb. 28 that portions of the parkway were “undeniably unsafe to drive upon.” His assessment was quickly validated on the social forum by a Park Service spokeswoman who agreed that the conditions “are pretty bad.”

“I do hope they fix the road,” Mann said in an interview. “If they want to address it by saying we want traffic to slow down . . . that is one thing, but what’s the plan for the long term?” he said.

Park Service officials say the partial government shutdown this winter did not slow maintenance work on the highway, but inclement weather prevented crews from patching potholes until the final days of the funding lapse.

The proliferation of potholes in recent weeks has led to thousands of service calls from drivers stranded on the region’s roads. Crews from AAA emergency roadside assistance rescued 10,196 members with flat tires across the Mid-Atlantic region, including nearly 5,000 in Maryland, Virginia and the District in the final two weeks of February, according to the group.

AAA is averaging two to three calls a day from members who need assistance on the parkway because of a flat tire or damaged rim — about average for this time of year, the group says. But the number of stranded motorists is probably much higher, because a lot of people try to change tires themselves, according to accounts from roadside assistance crews.

Officials with AAA Mid-Atlantic said they worry that lowering the speed limit will have little effect on a roadway known to suffer from traffic jams and an “unsafe driver culture.”

“This could be a double-edged sword that might create more unsafe driving and more dangerous conditions and crashes on one of the most dangerous roadways in the Washington metro area,” AAA spokesman John Townsend said.

But Park Service officials say the lower speed limit will remain in effect “as long as it’s necessary” to keep travelers and road crews safe.