Baltimore and other Maryland localities would receive millions of dollars in federal money for bicycle trails, scenic pull-offs and street beautification projects as part of a huge, bipartisan transportation bill expected to pass in the U.S. Senate as early as Tuesday.

The provision to protect funding for trails and other “transportation enhancements,” as the projects are known, was threatened in an earlier version of the $109 billion highway bill. Now the measure includes the funding and would give local leaders more control over how to use the money, which could bring speedier improvements to the Herring Run and Jones Falls trails in Baltimore.

Preservation of the trail funding is something of a political coup for Sen. Ben Cardin, who waded into one of the more controversial aspects of the transportation legislation and managed to appease both skeptics and bicyclists, who say trails often take a back seat to road maintenance and transit. The provision would still require approval in the Republican-led House of Representatives.

Maryland received $12.3 million for the projects in 2010 out of $886 million available nationwide.

“It offers cities a fair shot at getting these resources and making sure they’re used for the beneficial purposes the programs have supported in the past,” Kevin Mills, vice president of policy and trail development at the Rails-to-Trails Conservancy in Washington, said of the provision.

He said Cardin, a Maryland Democrat, “mitigated some of the most glaring problems” with the bill “in a way that navigated treacherous waters of disagreement.”

The provision is tucked into the large two-year bill that funds highway and bridge repair. Congress must pass the legislation by the end of the month or risk disrupting construction projects and suspending the collection of federal gas taxes in the middle of the nation’s fragile economic recovery.

Some bike riders in Baltimore say the money would be a good investment.

“If it makes it easier, I think that’s going to mean fewer people on the road commuting,” said Elizabeth Hazel, a 32-year-old Hampden woman who said she uses the trails recreationally. “It also just makes the city a nicer place to live — it just increases the livability of the city.”

In past years, the federal money has been used to help build the 15-mile Gwynns Falls Trail in Baltimore and extend the Maryland and Pennsylvania Railroad trail, familiarly known as the Ma & Pa, in Harford County.

Baltimore officials said they hope future funds will help pay to extend the Jones Falls Trail from Cylburn Arboretum to the Mount Washington light rail station and begin improvements to the Herring Run trail.

The number of people commuting by bike in Baltimore has risen by 40 percent over the past three years, according to estimates from the city’s transportation department. It’s not clear how many of those riders are using trails and how many are commuting on local streets.

The enhancement program has faced scrutiny in Congress. Republicans such as Oklahoma Sen. Tom Coburn have highlighted examples like a $3.4 million tunnel built to allow turtles to cross a busy Florida highway. More broadly, opponents say state officials should be able to decide where to spend federal transportation dollars rather than being forced to set aside a portion for trails and other enhancements.

State control over the funding is particularly important as governors wrestle to balance state budgets and meet the maintenance needs of aging roads and bridges, opponents say.

“A lot of organizations go to the national level to second-guess the decisions made at the state level,” said John Horsley, executive director of the American Association of State Highway and Transportation Officials. Horsley said his organization supports the broader legislation, but he added that he is worried Cardin’s trails provision will “create an administrative nightmare.”

Under current law, state transportation agencies are required to set aside about 2 percent of their overall federal transportation money for the alternative transportation projects, which can also include building bicycle facilities, mitigating the environmental impact of roads — such as by capturing polluted storm-water runoff — and roadside landscaping.

The Senate version of the transportation bill would make many more types of projects eligible for the money. The legislation also allows states to redirect some of the funding for other uses — such as road maintenance — if it is not being spent quickly enough for its original purpose.

Cardin and others said that provision would create a perverse incentive for state highway agencies to save the money so that they could spend it elsewhere.

“In tough budget times, the temptation might well be there to hoard these dollars and use them for other purposes,” said Cardin, who said that state and local officials in Maryland have historically worked well together on using the money for its intended purposes.

Cardin’s proposal, which he drafted with Mississippi Republican Sen. Thad Cochran, would immediately distribute half the money to local governments based on population, which would give local officials power over how to spend it. The state would then allocate the rest through competitive grants.

Maryland cities and counties are not likely to receive more money than they did this year — in fact, advocates say the Senate bill would slightly cut the program.

Cardin’s amendment faced little opposition and was included in a broader transportation bill expected to come up for a vote as soon as Tuesday . Its future is less certain in the Republican-controlled House, where leaders have abandoned a version of the transportation bill that made significant cuts to the enhancements program.

Republican House Speaker John Boehner has indicated he may take up the Senate’s bipartisan bill if lawmakers in his chamber don’t craft their own version in coming weeks.

Several bikers said the agencies that oversee Baltimore’s trails could use the money.

Rebekah Kuk, 30, biking recently along the Jones Falls east of Druid Hill Park, described the trail as “well kept” and “nicely landscaped,” but said it would be more useful if it extended farther south into downtown Baltimore.

She also said the city should do more to promote it.

“They have to tell people about it,” she said. “There’s not the marketing to go with it.”

Biking through the same spot, 28-year-old Kial Stewart said he uses the trail a couple of times a week to get from downtown to the Johns Hopkins University, where he is doing postdoctoral work. He said he’d use the trail every day if it were better maintained and extended farther south.

“This stretch of the trail, I guess it doesn’t get much attention,” said Stewart, motioning to the trail snaking along the Jones Falls south of 28th Street. “Even though it’s sort of in a state of disrepair, it’s so much nicer because you don’t have to fight the traffic.”