Slowly but surely, the rent-by-the-hour car company Zipcar is creeping into Dorchester, mostly along the path of MBTA’s Red Line.

One new car was added to the Savin Hill T Station site, one of eight locations in Dorchester. The sites are clustered around the JFK/UMass, Savin Hill, and Ashmont stations.

The company has been criticized by many around the country for focusing on more affluent white communities, and in Boston, their pattern reflects the same, with hundreds of cars in the upscale sections of Brookline, Cambridge, and Somerville. In Boston, the company positions its cars mostly in Back Bay, the South End and the North End, with only 20 cars so far in Dorchester, the city’s largest, and possibly most diverse neighborhood.

But Boston Zipcar’s general manager Dan Curtin says the company follows its subscribers, trying to place one car for every 50 drivers that subscribe to the service—though he said the company does not release those numbers. Zipcar also pulled several cars out of Jamaica Plain a few years ago, where the service was very popular and growing, after two window-smashing incidents.

“We’ve been around for 10 years and we started in Central Square. A key part of this growth is key members talking to others, it starts at the center and moves out,” said Curtin this week. He also cited the service’s popularity in densely populated areas with chronic parking problems.

“We’re actively looking in Fields Corner and around Ashmont and anything we can fill in along Dorchester Ave.”