Kim Smith, a 48-year-old teacher and mother of four, lives in Philadelphia's gentrifying Point Breeze neighborhood, where the city in April placed one of its racks of bright blue bicycles as part of the Indego bike-share program.

As one of the 19 program ambassadors, Smith has keen interest in getting her friends and neighbors on the 1200 block of South 15th Street and throughout the lower-income neighborhood to take advantage of the hourly bike rental.

Her message to wary neighbors has been consistent.

"This resource was put here for all residents," she said.

Bike sharing has taken off in U.S. cities in the last five years, as part of a push to improve health and to reduce traffic congestion and auto emissions in urban areas. In April, when Philadelphia launched its program, the National Association of City Transportation Officials released a study that showed low-income people do not participate proportionally in bike sharing.

"There's a perception of biking being for wealthier people who are not minorities," said Paul DeMaio, who was integral to launching Capital Bikeshare in the Washington area. "It's overcoming these hurdles that we're all facing."

Overcoming that perception is an important goal of the Indego program. The city is riding the national bike-sharing trend and the emerging "sharing economy." Philadelphia faces the same myriad challenges - marketing, pricing, public and private funding - as other urban centers to make Indego a sustainable business that is accessible to residents across the city's income spectrum.

The Mayor's Office of Transportation and Utilities is evaluating bike-share ridership data for demographic details on participation. Officials would not provide the number of renters by station - except for the few highest-volume stations - among the city's 73 Indego stations, but did provide the riders by zip code. Officials said appealing to a diverse group of city bike riders remains a priority - and a struggle - for the program.

"I want as many people as possible to think Indego is for them," said Denise Goren, the office's director.

In Philadelphia, where U.S. Census data show a 26 percent poverty rate and the highest level of deep poverty among the nation's 10 largest cities, bike-share organizers see Indego as a new transportation asset for the city's poor.

But the majority of bike-rental stations now are in higher-income areas of the city. Of the 25 bike-rental stations in neighborhoods with average annual household income of $54,367 (the city average) or less, 18 are near Temple University, the University of Pennsylvania, or Drexel University.

Officials said they had to balance outreach to the city's poorer communities with budget limits and the demand for bike sharing in wealthier neighborhoods. A 2016 expansion plan will add 24 more stations, some in low-income areas, probably in South and West Philadelphia, officials said.

Since its spring launch, Indego has drawn 7,250 monthly members. An additional 40,000 people paid for single rides on the program's 700 rental bikes. About $900,000 in member-related fees is projected to cover about 80 percent of Indego's costs, officials said.

"It's way ahead, almost in some cases double" the number of users for the same period in Washington and Boston, said Russell Meddin, Bike Share Philadelphia's founder, who lobbied for years for the city to start a bike-share program.

Capital One Bank recently sponsored Indego. In September the William Penn Foundation gave a $1.5 million grant to help pay for the additional stations.

Indego allows people to pick up bikes at stations around the city, ride to another one nearer to their destination, and drop off the bikes. Ridership data indicate a surge of riders at 8:30 a.m. and 5 p.m. daily, Goren said, which suggests that riders use Indego bikes to commute to and from work or school.

"It's the easiest way to get around," said Bob McDermott, 24, a Temple University research fellow, as he docked a bike at a station on John F. Kennedy Boulevard, near City Hall. McDermott rides to work from Ninth and Spring Garden Streets. He cited the $15 monthly membership fee and the freedom of riding a bike as reasons for using Indego.

"When you're going diagonally across the city, it's easier to bike," he said. "You can get exactly where you need to go."

Brian Johnston, 37, of Fairmount, uses Indego either in combination with a bus or as his sole means of travel to work at a Fresh Grocer on Broad Street near Temple.

"It's real convenient," he said. "It's fast."

The monthly fee pays for unlimited one-hour rides. Indego also offers a limited-use monthly membership for $10, and walk-ups can get a bike for $4 a half-hour ride. By comparison, a SEPTA monthly bus city Transpass costs $91.

Many cities, including Washington, Boston, and Chicago, have established bike-share programs. This, officials say, gives them lots of places to look for ideas to build ridership in Philadelphia.

Officials say the reasons for the small number of low-income riders in Inedgo's first six months include a lack of stations in their neighborhoods, low awareness of the program, and difficulty paying for the bike rental.

While researching where to put bike-share stations, the city placed stickers on streets inviting people to send text messages if they wanted a bike station in their community, said Andrew Stober, now a candidate for City Council, who led the planning and implementation of Indego. Even at stations in higher-income neighborhoods, organizers sought ways to maximize access. A station in Queen Village, he said, was placed next to public housing.

Philadelphia is one of the few major cities with a bike-share program offering a cash-payment option, officials said. Only 50 of Indego's more than 7,000 monthly members pay for membership with cash, officials said.

Ka'ymer Luis, 19, of Kensington, is exactly the kind of user Indego hopes to attract. At the station on JFK Boulevard, he said he used Indego twice a week, often to get to his destination faster after getting off the subway, he said. Without Indego, he said, "I'd probably be walking."

Meddin, of Bike Share Philadelphia, said the city could do more to attract diverse Indego ridership. The $15 monthly membership fee, spread out over a year, is among the country's highest for a bike-share program, he said. And Indego does not offer a discounted annual membership. Indego's rate for nonmembers, $4 a half-hour, is higher than that for a single ride on a SEPTA bus or train. In Chicago, $5 will pay for an annual bike-share membership for individuals who qualify as low-income. In Boston, monthly membership costs $20, but an annual membership is $85. In Washington, riders also can pay $85 up front for an annual membership or choose an installment plan of $8 a month. In both cities, membership covers only the first half-hour.

Meddin also would like to see more bike-rental stations in Philadelphia. In 2013, the city's plan for Indego called for 150 to 200 stations.

Initial bike-station placement balanced density with a desire to serve more neighborhoods, Goren said. Surveys of potential riders established $15 a month as reasonable, she said. Officials said monthly payments, rather than a lump sum for annual membership, make it easier for those with less money to pay.

Smith continues working to share the benefits of bike sharing with her Point Breeze community. Sometimes, when out with her 4-year-old daughter, she sees a bright-blue Indego bike pass by.

She was happy, she said, when her daughter excitedly said, "Mom, they're riding your bikes."