Ridesharing apps like Lyft and SideCar have been surging in popularity over the past few months in San Francisco's taxi desert. In fact, we'd be willing to bet more than a few frustrated transit or cab riders ended up being satisfied customers after hopping a ride with SideCar, Lyft or Uber over this past weekend.

The general consensus among riders we've talked to (anecdotal evidence, sure, but useful nonetheless) has been overwhelmingly positive. The California Public Utilities Comission, on the other hand, sees them as "unsafe, illegal and risky."

As the Chronicle reports today, the CPUC has issued a cease-and-desist order to both Lyft and SideCar, claiming neither company has the required carrier permits that make sure the drivers have the proper licenses and insurance to carry commercial passengers. So far, the two companies have skirted the commercial passengers issue by claiming fares are paid as "suggested donations."

For their part, all three companies have been touting the in-house driver screening processes and insurance policies. Lyft, for example, conducts DMV and background checks on new drivers, and recently announced a $1 million excess insurance policy. So, it seems the CPUC's real beef with SideCar and Lyft is that the startup companies have managed to offer a solution to the cab shortage that didn't get hung up in the bureaucracy. (Until now, that is.)

According to the commission, SideCar and Lyft will need to obtain $1,100 charter party carrier licenses, only given out after the CPUC has vetted each company's licensing, screening and insurance policies. Under the cease-and-desist order, there's a chance vehicles could be impounded and drivers could face penalties up to $5,000 per day and up to three months of jail time, just for schlepping you and your pals from the Mission to North Beach on a Friday night. In the case of Lyft and SideCar, drivers are regular folks in their Hondas and Priuses.

Uber received a similar cease-and-desist shortly after that company started up back in 2010. Judging by the very pleasant ride out to Golden Gate Park our Uber driver Steve gave us on Saturday, that hasn't slowed the company down yet, but the Public Utilities Commission says that Uber is still under investigation.

Meanwhile, the cab companies still aren't happy about the startup services which they like to call "rogue cabs." The SFMTA is launching its own investigation into all three companies, but in the meantime, we're still waiting for them to process all the paperwork on those 150-200 new taxi permits they promised last month.

Note: SideCar has also weighed in via a blog post this morning, stating very clearly: "SideCar is not a charter-party carrier."

Previously: More On Those Pink Mustache Cars, And Why They're Good; Hail! City To Issue 150-200 New Taxi Permits