Keith Pollock, who oversees the city's taxi program, said other regulations — uniform vehicles, an assurance that riders won't refuse fares and will operate in all parts of the city, the posting of rates on the door — are not followed by the new services.

So far, he said, the city hasn't taken an official position on the companies. Wednesday's meeting is strictly informational.

"This is a new kind of breaking issue," he said. "I don't think a lot of the (Transit and Parking Commission) members and some of the alders are aware of it. We're going to have all the cab companies come. We're hopefully going to have Uber and Lyft come, and the city attorney will be there just to explain the current laws as they pertain to public passenger vehicles."

One of the most contentious issues that has arisen from the new taxi services is liability. Both Uber and Lyft claim to have $1 million commercial insurance policies for passengers.

But in San Francisco, where an Uber driver is being sued for wrongful death for killing a 6-year-old girl, Uber's liability in the tragedy isn't so clear and Uber doesn't want anything to do with the case.