I bumped into Sunil Paul, CEO SideCar, at Hub SoMa in San Francisco last Wednesday and we shot this impromptu interview about the progress of his real-time ridesharing service, which is currently in the process of working out significant regulatory challenges.

SideCar is a ridesharing smartphone app that connects drivers with riders in real-time. It's become a huge hit in San Francisco since it launched last June, and the breakout of real-time ridesharing services is one of the unexpected sharing success stories of 2012.

Sidecar beta tested in San Francisco for six months building up a critical mass of drivers and riders before launching. Their test included over 10,000 rides. Once launched, it filled a huge unmet need in notoriously taxis-scarce San Francisco.

In October, the PUC issued a cease and desist order to SideCar and similar services. The crux of the issue is that under existing regulations, drivers providing compensated transportation services are required to have "charter party carrier" permits that make sure drivers are licensed, screened, and insured. SideCar screens and insures drivers, but still ran afoul of regulations, which did not forsee nor were intended for these new technology-enable peer transporation services. The oft-stated concern of the PUC is safety, though it's clear that taxi interests see Sidecar and their ilk as a direct threat to their business.

Interestingly, none of the services served cease and desist orders stopped operating. This resulted in SideCar and others being fined $20,000 in November. According to Paul, discussions with the PUC since the fine have been constructive and are heading down a path that treats real-time ridesharing services differently than taxi and livery services. We'll see.

In any case, none of this is stopping Google-backed SideCar from pursuing national expansion plans. As Paul states in the interview, SideCar recently launch in Seattle as preparation for a national rollout. And while the conflict is with regulations that govern taxi services, the real target of disruption for Paul is car ownership. He sees SideCar and other innovative mobility options like peer to peer carsharing as a replacement for car ownership and car owners driving and bearing the cost of ownership alone. With the high financial, social, and environmental cost of cars, let's hope this is a service whose time has come.