Ride-hailing company Lyft has debuted Lyft Shuttle, a new service that allows commuters to get picked up and dropped off along a fixed route, at predetermined locations.

For the moment, Lyft Shuttle is being tested in San Francisco and Chicago. A map sent to the Examiner shows pre-set stops in the Marina, Fillmore, Lower Haight, SoMa, and FiDi, among other spots. 

Lyft Shuttle is intended to operate as a rush-hour extension of Lyft Line, the company's carpool service. (It runs from 6:30-10am and 4-8pm on weekdays.) But unlike competing SF shuttle service Chariot, drivers use their own cars, with passenger pick-up and drop-off at select locations, instead of door-to-door travel. Prices vary according to time and distance, though they are not subject to surge pricing.

The system has drawn concern from the SFMTA, which is worried about Lyft Shuttle or similar services cutting into bus and train ridership. 

“It’s more privatization of our public sector and our public transportation system,” Sue Vaughan, a member of the SFMTA's citizen advisory council, told the Examiner. “We need to have a big conversation about this.”

A representative for the SFMTA's taxi division said the agency will be looking into whether Lyft Shuttle falls under its jurisdiction. It's not yet clear if new laws regulating private bus shuttles in the city, which are currently in the works, would also have an impact on the service.

Lyft's idea is not new. In 2015, Uber piloted a similar service, called UberHop, in Seattle, which paired riders traveling a similar route. Uber also tested a bus-style service called Smart Routes, which let customers set a pickup location along a fixed route. 

Last year, Lyft itself shut down a carpool commute feature in the Bay Area, after a failed attempt to find enough participating drivers.