Anthony Roberts set out to walk to a convenience store on the opposite side of a busy highway in Kansas City, Mo., one afternoon. It wasn’t an easy trip.

First, he had to detour out of his way to reach an intersection. Then he had to wait for the light to change. When the walk signal finally came on, he had little time to cross several lanes of traffic and reach the highway’s wide median. Finally, he had to make it across the other set of lanes to complete his trek.

“For a person who doesn’t have a car, it’s very hard, especially in the wintertime,” Mr. Roberts said. “No one wants to take a risk with their lives trying to cross the highway.”

Mr. Roberts’s journey is a small example of the lasting consequences stemming from the construction of highways slicing through urban neighborhoods in cities around the country. Completed in 2001 after being in the works for decades, the highway in Kansas City, U.S. 71, displaced thousands of residents and cut off predominantly Black neighborhoods from grocery stores, health care and jobs.

Kansas City officials are now looking to repair some of the damage caused by the highway and reconnect the neighborhoods that surround it. To date, the city has received $5 million in funding from the Biden administration to help develop plans for potential changes, such as building overpasses that could improve pedestrian safety and better connect people to mass transit.

The funding is an example of the administration’s efforts to address racial disparities resulting from how the United States built physical infrastructure in past decades. The Transportation Department has awarded funding to dozens of projects under the goal of reconnecting communities, including $185 million in grants as part of a pilot program created by the $1 trillion bipartisan infrastructure law.

But the project in Kansas City also shows just how difficult and expensive it can be to reverse long-ago decisions to build highways that slashed through communities of color and split up neighborhoods. Many of the projects funded by the Biden administration would leave highways intact but seek to lessen the damage they have caused to surrounding areas. And even taking out a roadway is just a first step to reinvigorating a neighborhood.

“Once you wreck a community, putting it back together is much more work than just removing an interstate,” said Beth Osborne, who served as an acting assistant secretary at the Transportation Department during the Obama administration and is now the director of Transportation for America, an advocacy group.

The United States has a long history of highway projects dividing urban communities that dates back to the construction of the federal interstate highway system in the middle of the 20th century. In recent years, the idea of removing some of those roadways has gained traction in cities around the country, including Detroit, New Orleans and Syracuse, N.Y.

In his first year in office, as part of his infrastructure plan, President Biden proposed a $15 billion federal program to help bring improvements to communities harmed by the construction of transportation infrastructure. His original proposal was whittled down to a much smaller program, with $1 billion in funding, in the bipartisan infrastructure package that Congress later approved.

The Transportation Department announced the first batch of grants under the program in February, awarding $185 million to 45 projects. The grants included about $56 million to help build a deck over an expressway in Buffalo and $30 million to go toward redesigning an urban freeway in Long Beach, Calif.

In a visit to Buffalo after the grants were announced, Pete Buttigieg, the transportation secretary, said that planners of some highways had “built them directly through the heart of vibrant communities — sometimes to reinforce segregation, sometimes because it was the path of least resistance, almost always because Black neighborhoods and low-income neighborhoods did not have the power to resist or reshape those projects.”

“Now, most of the people who made those decisions aren’t around today,” Mr. Buttigieg continued. “No one here today is responsible for creating that situation in the first place. But all of us are responsible for what we do in our time to repair it, and that is why we’re here today.”

Kansas City officials received just over $1 million from that program to study how to reconnect another part of the city, the Westside neighborhood, which is separated from other areas by a different highway, Interstate 35.

The Transportation Department is also using other grant money to support projects meant to stitch communities back together. The $5 million award that Kansas City received to address the impact of U.S. 71 came from a program called Rebuilding American Infrastructure with Sustainability and Equity, or RAISE.

The grant is meant to help the city devise plans for improvements along one stretch of the highway. City officials are not seeking to remove the roadway altogether, but they want to make it safer for pedestrians to get from one side to the other. Building overpasses could spare residents from the dangerous trip across the highway on foot and make it easier to get to a nearby bus route.

The idea for what is now U.S. 71 can be traced to the 1950s, when it was envisioned as a way to connect downtown Kansas City with areas to the south. A legal battle in the 1970s and 1980s delayed construction for more than a decade, and a portion of the route was ultimately refashioned into more of a parkway. Thousands of people, including many Black families, were displaced to make way for the 10-mile roadway, which is also known as Bruce R. Watkins Drive.

Its construction left a lasting imprint on Kansas City. The city’s Country Club District, a group of historic neighborhoods west of the highway where homes commonly fetch upward of $1 million, was untouched by the roadway. The area to the east of the highway is markedly different, with lower property values and more abandoned and foreclosed homes.

Kansas City’s mayor, Quinton Lucas, said it was impossible to live in his city and not know the scar that the highway left on the Black community. Churches, schools and businesses disappeared after it was built, he said.

Mr. Lucas said that fighting to undo the damage caused by the roadway — and righting the wrongs that had affected the city’s Black residents — was a top priority for him.

“It’s how to make sure we are linking businesses on both sides, how do we make it easier for people who can cross without a car and how to engage a neighborhood and not have them known as just a highway,” he said.

Ron Hunt, who for decades has lived in the Blue Hills neighborhood west of U.S. 71, said he had watched the highway cripple the area economically, drive up crime and limit access to grocery stores. Mr. Hunt said that as other parts of the city continued to grow and blossom, it pained him to see his community wilt after the highway was built.

Residents like Lisa Ray are trying to preserve what remains of neighborhoods they loved. Ms. Ray grew up in Town Fork Creek just east of U.S. 71, which was once a pleasant middle-class area filled with Black-owned businesses. But the highway destroyed it, she said.

“It sounded good 40 years ago when they first started this project,” she said. “It did not turn out the way any of us thought it would.”

Now, she and other members of the Town Fork Creek Neighborhood Association volunteer to provide food and other necessities to elderly residents whom the highway has cut off from grocery stores. They also buy trash bags and organize cleanups to keep bottles, car parts and papers from lining the streets. The neighborhood association has spent money purchasing door security bars to help prevent break-ins in the area.

“All we do is try,” Ms. Ray said. “I try every day, block by block. I can’t help everyone, but I do try.”

Kitty Bennett contributed research.