Lyft and Sidecar say they have measures to ensure passenger safety. They interview drivers, check driving records, conduct criminal background checks and inspect vehicles. Drivers use their own insurance, but both companies provide additional coverage up to $1 million.
Other cities and states are also figuring out how to regulate the new transportation apps. The International Association of Transportation Regulators is working on guidelines for regulations that, if adopted, could restrict the upstarts.
Internet-based ride-hailing apps should be regulated, but regulators must be careful not to quash innovation in a transportation sector, said Daniel Sperling, director of the Institute of Transportation Studies at the University of California, Davis.
Sperling believes technology can reduce congestion, pollution and greenhouse-gas emissions by making transportation more efficient and convenient, allowing more people to live without personal cars.
"This is the first wave of what we hope will be a whole series of innovative companies and technologies that will transform transportation as we know it," Sperling said.
Lyft launched in San Francisco in June and began offering rides in Los Angeles on Thursday. It's cultivated a playful image with its pink mustaches and fist-bump ice-breakers. Users sign up with their Facebook accounts.
To maintain safety and quality, both Lyft and SideCar ask passengers and drivers to rate each other after each ride. Too many low ratings, and they're booted from the network.
Both services have attracted a diverse group of drivers. Lyft drivers include PhD students who need a break from writing dissertations, preschool teachers looking for adult conversation and artists seeking to earn extra money, said Green.
San Francisco State University student Shelby Stone, 23, drives her black Volkswagen Rabbit for Lyft four or five days a week to help pay car expenses and other bills.
"I have a blast with Lyft," Stone said after dropping off passenger Kutscher by Union Square. "All day long I'm meeting new people and getting to know the city of San Francisco."