Houston taxi drivers showed up at a City Council committee meeting Tuesday to protest the possible entrance of two ridesharing services, Uber and Lyft, into the Houston market.

The cabbies wore T-shirts bearing the words "Licensed, Insured, Legal," reflecting the established taxi and limousine industry's contention that the new services, which rely on non-professional drivers using their own vehicles, don't provide the needed safeguards to protect the public.

Two council committees met jointly to consider possible changes in city regulations that would enable Uber and Lyft to operate legally in Houston. For now the companies are avoiding regulation by providing free rides, although the industry contends even this is unlawful.

"Our main concern is public safety," the Houston Area Livery and Charter Association said in a statement. "When you have an operator that has to do 100 trips per week to break even, properly maintain their vehicles, secure proper insurance coverage and licensing, the math doesn't add up."

Uber, meanwhile, is seeking signatures on an online petition urging the city to allow the company to operate in Houston.

"In 2013, Houston was named America's next great global city," the petition states. "Unfortunately, a lack of modern transportation options are handcuffing that future."