As he does most evenings, Scott — who only wanted to be identified by his first name — arrived at Union Station, having taken the MARC train from his job in Baltimore.

He stopped at one of the 54 red Capital Bikeshare bikes that covered nearly an entire block on the east side of the station. Instead of trudging the mile home, he rode off.

“It’s just quicker,” he said. Every few minutes around 5 p.m. one recent evening, others — all of them white — said much the same thing. Like three-quarters of regular Capital Bikeshare users, they got off the Metro and pedaled home.

According to a study released last month by the Urban Institute, you’re far more likely to have this convenience if you’re white, make more money and live west of the Anacostia River.

The study raises questions about the equity of the popular bike program, which allows people to make unlimited short trips for an annual $85 fee, or pay $2 each for rides shorter than 30 minutes. (Longer trips cost more.)

The Feb. 11 study found that census tracts in the District with the largest percentage of white residents had an average of 2.36 bike stations, whereas the least-white areas had only 0.62.

Areas with the highest percentage of people making $75,000 or more had on average 2.25 stations, while the least-well-off areas had half as many — 1.02 stations. The study did not look at other bike or scooter rental companies.

Capital Bikeshare did not respond to inquiries about the report or why bikes are placed where they are. City transportation spokesman Terry Owens said a number of factors come into play, but one is that the program wants to emphasize putting new bike stations in the city’s core — “otherwise, when trips are made to the central business district, there may not be docks available for the new bikes.”

To make the program more affordable, Capital Bikeshare does offer a membership for $5 a year to low-income people. On Feb. 26, the city also announced a new program to give veterans free memberships to the bike-share program.

But the Urban Institute report, “Three ways bike-share can counteract, not reinforce, DC’s disparities,” said it’s not clear how many people know about the discount for low-income people.

Capital Bikeshare, in a report on the results of a 2016 rider survey, acknowledged it hasn’t made much progress in diversifying. Eighty percent of survey respondents were white, about the same as the 84 percent in 2014.

Yipeng Su, one of the authors of the Urban Institute’s report, acknowledged the program faces a conundrum: Even when bikes are put in lower-income neighborhoods, they’re barely used. Four of the five least-used Capital Bikeshare stations in 2017 — the most recent year examined by the Urban Institute study — were east of the Anacostia River.

During an hour of the afternoon rush one day last week, no one grabbed any of the five bikes outside Metro’s Anacostia station after they got off the Green Line. The area directly around the station has the lowest income of the city’s 40 Metro stations.

“My bike-riding days are over,” said one man in his 40s. Another said he didn’t trust using his credit card to rent a bike. Others carrying construction helmets said they didn’t feel like pedaling home.

To Su, it makes sense to put bikes where they will be used the most. But that also makes other disparities worse, she said.

Poorer communities are less likely to have bike lanes, she said. So if that makes it less likely for lower-income people to ride bikes, then making bikes available based on ridership would just make it even less likely for people in poorer areas to have the same options as those in wealthier areas.

The number of stations is also significant because the bikes cannot just be left sprawled on the sidewalk like scooters. They have to be docked at another station. If a neighborhood doesn’t have many stations, there aren’t many places to drop the bikes off.

Renee Moore, outreach coordinator for the Washington area Bicyclist Association, who lives in Anacostia, said that makes it even less likely that people in lower-income areas will be able to use the bikes.

She noted that most of the Capital Bikeshare stations in lower-income areas tend to be around Metro stations or community centers. But the dearth of bikes means they’re less likely to be near people’s homes than in richer areas.

So if people in poorer areas want to bike to the Metro, they’d have to go to the train station to find a bike. “And that defeats the purpose,” she said.