Boston’s weeks-old Hubway bike share program is in full swing, but many local advocates wonder when Dorchester and Mattapan commuters can expect a ride on some of the program’s 600 bicycles.

After three years of planning and negotiation, the Hubway system currently offers 61 bike rental stations located in densely populated downtown neighborhoods including the North End, Back Bay and Downtown Crossing and extends outward to a handful of pick-up points in Allston and Roxbury. But no stations have been located near Dorchester or Mattapan.

Nicole Freedman, Boston’s director of bicycle programs, said the program has focused on downtown neighborhoods in hopes of maximizing exposure to the system and attract the largest number of possible users. Freedman said the program gathered 500 registered users before its July 29 inception, a number that has swelled to 1,700.

“The general enthusiasm we’re seeing from people has been fantastic,” Freedman said.

Despite the Hubway’s positive reception by commuters and tourists, Freedman said the program is dependent on having rental stations positioned no more than 400 meters apart from one another to minimize time spent walking from a drop-off to a user’s final destination. Because of this design requirement, Freedman said the Hubway would extend outward “in bits” as additional funding becomes available, resulting in as many as 200 stations citywide – including a chain of stations that would lead down Dorchester Avenue toward Ashmont Station.

While officials say the program will gradually extend into Boston’s outer neighborhoods and neighboring towns, local health and bicycle advocates say more could be done to make their neighborhoods inviting to potential riders regardless of whether they own or rent their wheels.

Mattapan Food and Fitness Coalition member and cyclist Theresa Jordan said increasing ridership throughout Mattapan would be a major step toward combating the area’s nearly 70 percent adult obesity rate and sees the Hubway as a useful means to reintroduce lapsed riders to city roads; however, the lack of bike lanes and racks in the neighborhood make for a tough sell to new bikers.

“Biking is definitely something people in Mattapan want to do,” Jordan said. “We want people to consider riding in to Mattapan Square, but with so few bike racks, there’s no incentive for anyone to ride, there’s very little opportunity.”

Jordan also said that while the city has begun to extend bike lanes into parts of Dorchester, major roadways like Blue Hill Avenue are still treacherous for all but the most confident riders.

Dorchester resident and bicycle blogger Phil Lindsay has been a harsh critic of the Hubway system, saying that underlying safety concerns need to be addressed before more cyclists are introduced to Boston streets.

“[The Hubway] has distracted us from the real job that should be taking place, it’s something you talk about once you have the rest of the infrastructure in place for all riders,” Lindsay said. “All the energy and resources that’s been spent on planning it in the past three years could have gone towards adding more bike lanes and educating drivers.”

Lindsay also added that the $85 registration fee could make the program prohibitively expensive for riders who may avoid the system altogether and invest in a used bicycle for around the same price, creating “a Hubway of their own.”

Despite concerns from some residents, Ashmont Cycles owner Jack Pelletier said he hopes the program will encourage people to hit the pedals in their daily life.

“I would definitely welcome bike sharing in Dorchester,” Pelletier said. “Anything that has more people on bikes, or familiar with them is totally fine by me.”

Pelletier opened his shop earlier this season and said that based on the number of curious customers and families bringing in old bikes in need of tune-ups, the area is full of potential Hubway users.

While many bicycle advocates were unhappy to learn outer lying neighborhoods would have to wait for stations of their own, Pelletier drew an optimistic analogy between the Hubway program and Zip Cars, which he recalled began largely in downtown Boston but quickly expanded to encompass much of the city.

“The thing is, something like this is going to take some time,” Pelletier said. “People need to get used to seeing the system around. When it gets popular, you’ll start to see stations cropping up.”

For Pelletier, the real issue is not whether someone owns or rents their bike, but rather that they remain a visible presence on the road, serving as a reminder to drivers and cyclists that they are part of a larger – hopefully safer transit system.

“There’s no quick fix [to sharing the road,] it’s going to be a long mindset change for everyone,” Pelletier said. “A change I hope the city stays committed to in the coming years.”