Maryland’s roads, mass transit services, storm water management systems and other infrastructure received an overall “C” grade in the latest report card from the American Society of Civil Engineers.

The grade — though described as “mediocre, requires attention” — was still slightly improved from the “C-minus” on the organization’s last state infrastructure report card in 2011.

Maryland also outperformed the nation’s overall D-plus grade in 2017.

Sen. Ben Cardin (D-Md.) called the engineering group’s report card “extremely valuable” and proof that Congress should increase funding to repair the nation’s infrastructure and boost the economy.

The state’s slightly higher grade “tells us we’re making progress,” Cardin said during a teleconference on the report’s release Thursday. “But we have a lot more work to do, and the federal government needs to step up to the plate.”

A similar report card for the District is planned to be released later this year, a spokesman for the engineering group said. There is no time frame for a Virginia report card. The spokesman noted that the report cards are done by local engineers volunteering their time.

Two media representatives for the Maryland Transportation Department did not respond to two emails and two text messages seeking comment on the report’s findings.

Maryland earned its highest mark — a “B” — for its bridges, which the group said are among the best in the country. Nationwide, 8.4 percent of bridges, which include highway overpasses, are considered structurally deficient. In Maryland, 274 of 5,357 bridges, or 5.1 percent, fall into that category, according to the report.

That classification doesn’t mean those bridges are unsafe, the organization said, but rather that vehicle speeds and weights might need to be restricted to keep them open. Replacing all of the Maryland bridges in “poor” condition would cost $623 million, the report said.

The group credited Maryland’s “robust” bridge inspection program and dedicated funding to maintain and modernize its crossings. However, the report warns that one-quarter of the state’s bridges are over 60 years old — they’re typically designed to last 50 to 75 years — and that many will need more maintenance to extend their life.

Maryland received its lowest mark — a “D-plus” — for its transit systems, including MARC commuter rail, state commuter buses, and Baltimore’s light-rail, subway and bus systems. The group noted that the systems have a $2 billion maintenance backlog due to aging and outdated infrastructure.

The state has “significant budget shortfalls” to keep its transit systems, as well as its share of the Metro system, in a “state of good repair,” the report said.

“Maryland’s transit system has fallen behind and failed to meet the capacity needs of a dense population,” said Carrie Nicholson, past president of the engineering organization’s Maryland section.

While all transit systems require government subsidies, the report notes that Maryland’s systems need more public funding than others. That’s because fare revenue on Maryland’s transit lines covers 20 percent of their operating costs, compared with the national average of 32 percent.

The engineering group recommended fare hikes to help fund more repairs and maintenance work, which it said would improve on-time performance and, in turn, make people more likely to ride. Trains and buses that are late or unreliable are among the “systematic issues” caused by funding shortcomings that have contributed to eight years of declining ridership overall, the group said in a release.

MARC commuter trains have bucked that ridership trend, with trips growing by 2 percent over the past couple years, the report said, but the commuter rail lines run on schedule an average of 28 percent of the time.

“Quite frankly, our transit score is embarrassing,” Cardin said. “We haven’t invested in transit like we should.”

Maryland’s rail infrastructure, both for freight rail and Amtrak, received a “C-plus.” The group noted that funding is lacking to expand rail capacity, even as freight volume through the state is expected to double over the next 30 years and Amtrak is also expected to grow.

The state’s roads got a “C,” with 80 percent of the pavement in “fair to very good” condition. However, the group noted that 254 miles of highway, or 15 percent of the state’s highway network, has “heavy to severe” congestion. The state needs more highway capacity, the report said, including express toll lanes planned for the Capital Beltway and Interstate 270.

Maryland received a “C” for its storm water management efforts, due to the amount of pollution that hits streams and eventually the Chesapeake Bay after rain rushes off dirty pavement, farms and other surfaces.

Though Maryland’s approach is considered one of the most innovative nationwide, the report said, the Chesapeake Bay’s water quality has steadily declined over the past several decades due to insufficient treatment of polluted storm water runoff.

Erik Fisher, of the Chesapeake Bay Foundation, said he agreed with the “C” grade.

“There’s been a lot of investment in storm water in Maryland, but the truth is there’s plenty of work to do,” Fisher said. “We’re not where we need to be.”

Fisher said the state needs to require more retrofitting of older neighborhoods and commercial areas with rain gardens, landscaping and other methods that absorb and filter rain water that rushes off parking lots and other hard surfaces. While Maryland is known for some “very innovative” approaches to storm water management, he said, the state has to grapple with more water-filtering woods being cut down as it continues to grow and develop.

“It’s a big job, and we’re not making enough progress,” Fisher said.

Adam Ortiz, director of Montgomery County’s Department of Environmental Protection, said it’s a “critical time” for storm water systems to better protect the Chesapeake Bay.

“Our score is not where it needs to be,” Ortiz said, “but we’re also undoing literally four centuries of damage to the environment. . . . We have a lot of work to do.”

Maryland’s grade for its dams fell from a “C” in 2011 to a “C-minus.” Of the state’s 539 dams, about 130 are 50 to 60 years old. About 45 percent are “high hazard” or “significant hazard” dams, meaning their failure would threaten people, roads, homes and other buildings. The number of dams includes any wall or embankment designed to hold back or store water, even small ones that create neighborhood ponds.

The state’s drinking water systems received a “C,” mostly because of aging pipes that break and disrupt service. The group noted that Baltimore has stepped up its pipe replacements from five miles to 20 miles annually and that the Washington Suburban Sanitary Commission, which serves Montgomery and Prince George’s counties, has an “aggressive” program to replace more than 60 miles of pipe per year.

Even so, the group said, water utilities, which fund their pipe replacements and repairs via customers’ payments, need more funding. The report noted that the U.S. Environmental Protection Agency estimates that Maryland needs $9.3 billion in new drinking water infrastructure over the next 20 years.