Updated 02/17/15 – 11:42 a.m.

CHICAGO (CBS) — Some Chicago cab drivers staged a work stoppage Tuesday morning, protesting what they see as unfair competition from the less-regulated ride-sharing industry, a day after city officials granted a “transportation network provider” license to Uber.

Many cabbies drove through downtown for four hours Tuesday morning, refusing to pick up fares.

Dozens of cabs drive in circles around City Hall and the Daley Center for more than an hour, honking their horns to draw attention.

“It’s good music to my ears,” said cab driver Rocky Mmomo, a steering committee member of the United Taxidrivers Community Council.

Many cabbies had posted protest signs in their windows, accusing Uber of stealing their customers.

Mmomo said cabbies want the tax industry deregulated, so it can better compete with Uber and the other ride-sharing companies.

“We actually like that, because that actually calls for good competition,” he said. “It’s not good if you have one side highly regulated, and the other side unregulated. There are so many things that are wrong.”

The cabbies want the city to do away with chauffeur licenses required for taxi drivers, biannual city safety inspections required for all cabs, and medallions required to operate a cab company. A city medallion costs up to $375,000.

“We have 12,000 drivers who are suffering, because of the invasion of Uber, and UberX, and Lyft into the streets of Chicago; and that was as a result of the lack of regulation from the city of Chicago,” UTCC chairman Fayez Khozindar said at a City Hall news conference.

Cab drivers have said, because regulations on ride-sharing companies are much less restrictive, it’s very difficult for cab drivers to compete.

“We’ll be sitting at a hotel for two, three hours; and all of a sudden you see three UberX cabs just came and picked up customers while we’re just sitting there. How is that fair? That’s not fair to a cab driver,” cab driver Mustafa Husein said.

While plenty of cab drivers were taking part in the work stoppage, many others were picking up fares all morning, including outside the Palmer House Hilton, and at downtown train stations.

Even though some cab drivers did not participate, UTCC organizer Peter Enger said the protest was successful, because it sparked a conversation.

“We’re not calling it a strike, because the target of our action is to force a conversation with the city about UberX, and the ride-share industries, who are in the process of decimating the taxi industry,” he said.

Enger said, if the city is going to allow ride-sharing companies to operate, there should be a level playing field with existing cab companies.

“Instead of asking for more regulation (of ride-sharing), which this City Council and this mayor does not seem inclined to want, we’re asking let’s consider the option, which is deregulating the taxi industry,” he said.

On Monday, the city agreed to issue a “transportation network provider” license to Uber, after negotiations led to a promise from Uber to provide more stringent safety measures than required by the city’s ride-sharing ordinance.

Uber competitors Lyft and Sidecar were granted similar licenses three months ago.

Safety has become a major concern for ride-sharing services, especially after two Uber drivers recently were charged with sexually assaulting passengers in their cars.

Among other safety measures, Uber has promised to fully cooperate with police investigations of any complaints against their drivers, provide an in-app safety checklist every time a user requests a ride, use GPS to track the time and route of each ride, hire off-duty police officers as “secret shoppers” to conduct monthly audits of quality and safety issues, set up a notification to alert city officials when drivers are deactivated due to criminal charges or other safety issues, and implement a system to make Uber drivers easy to identify.

The company also has announced plans to implement a so-called “panic button” feature on its app, for riders to alert police if they feel threatened.

According to the Sun-Times, the city’s taxi industry has claimed Uber drivers “steal” 2 million rides a month from cabs, forcing 3,000 cab drivers to quit their jobs, and sending some taxi companies into bankruptcy.

Before the election next week, cab drivers want all five mayoral candidates to weigh in on the issue. Both Jesus “Chuy” Garcia and Bob Fioretti have said they support taxi drivers, and want a level playing field when it comes to regulating taxis and ride-sharing firms.