The shuttles are refurbished city buses. They have no straps or bars to hold onto -- the space is designed for seated passengers. Each bus fits about 30 people in either armchairs, banquettes or plush stools along a wooden counter.

Up front there is a mini-fridge with a selection of snacks and beverages for sale. Riders can order up things like Blue Bottle, Stumptown Coffee, Boxed Water and Happy Moose Juice -- a crowd favorite.

The bus seems to cater to the kind of tech-savvy professionals in its promotional video, but Kirchhoff says it is for everyone.

“We built Leap to be for all of San Francisco,” he says, “not one particular group of people.”

Yeah right, says Ilyse Magy. She is a representative from the San Francisco Transit Riders Union.

“I get triggered when I think about all of the people who don't have access to Leap,” she says.

Magy points to the price. A standard ticket costs $6 compared to $2.25 on a city bus. You need a smart phone to get on, unless you print your tickets, which means you need access to the Internet and a printer. There is no discount for young riders, no designated seating for the elderly or pregnant, and the bus is not wheelchair accessible.

“I get triggered when I think about all of the people who don't have access to Leap.” Ilyse Magy, San Francisco Transit Riders Union

San Francisco's public transit system needs improvement says Magy, but services like Leap do not help. She says Leap segregates the well-off from the rest of the city; it allows more privileged riders to opt out of the public system she says, which will eventually weaken it.

“When you have fewer and fewer people taking public transportation, but still voting on how it's funded and how it's managed, you have a voter base that is out of touch with the system,” Magy says.

Leap CEO Kirchhoff says he is not trying to disrupt Muni, but to get more people on mass transit.

“When Muni gets overcrowded, people go get in their cars and use car services, and we think that is worse for the city overall,” Kirchhoff says.

A private bus appeals to Malissa Schiermeyer. She is trying Leap because she wants a more comfortable ride than public transport. She has also tried taking Uber, which Kirchhoff sees as a competitor.

“When I work late and I can't take the express bus home -- how do I say this -- it's uncomfortable the amount of passengers and the type of passengers. Sometimes I don't feel safe,” Schiermeyer says.

“There is this libertarian philosophy that supports these private ventures and that is really destructive.” Erin McElroy, Community Organizer

Leap is one of many tech startups taking advantage of public irritation with San Francisco's public transportation. There is another shuttle company Chariot, and car services like Lyft, Sidecar and Uber. Leap has received funding from big names in Silicon Valley, like Salesforce CEO Marc Benioff and Netscape co-founder Marc Andreessen.

The whole startup approach to mass transit worries community organizer Erin McElroy. She runs the Anti-Eviction Mapping Project to fight for those getting priced out of the city by gentrification, and she would rather see more public approaches to issues like transportation.

“There is this libertarian philosophy that supports these private ventures, and that is really destructive,” McElroy says.

This is not the first time San Francisco has had private shuttles or jitneys. There were some back in the '50s and '60s, and there is still one shuttle that stops at the 4th and Market Caltrain station. But in the 1970s, San Francisco stopped the sale of jitney licenses. The rationale was to protect public transportation.

Right now it is unclear how services like Leap will be regulated. There have been complaints from residents and businesses about shuttles blocking driveways and causing congestion. City supervisors will hold a hearing on the issue, but probably not for at least a month.