California regulators say Uber, Lyft and Sidecar's car-pool services are illegal

Recently Uber, Lyft and Sidecar began rolling out a new type of service that lets their customers share their rides with strangers picked up along the way to their destination, then split the fare. Each company has its own brand name -- UberPool, Lyft Line and Sidecar's Shared Rides -- but essentially they work the same way. Right now, they're only available in San Francisco.

They may not be for long. This week the California Public Utilities Commission sent essentially the same warning letter to each of the companies, telling them that the new service violated state law. Charging individual fares to passengers when multiple people are being transported in the same car is against the law, the letter said.

None of the companies approached the Public Utilities Commission before rolling out the services, according to Denise Tyrrell, director of the agency's safety and enforcement division. "The commission lacks the flexibility to allow a transportation service that is contrary to the statute as approved by the legislature," she wrote in the letter.

Uber, Lyft and Sidecar may petition the California legislature to change the law, but otherwise the agency must enforce it, the letter said.

Each of the companies told the IDG News Service it would be working with the commission to address the issue. None of them said it would be suspending the new service, at least for now.