SEATTLE -- Uber is asking a judge to quash the City of Seattle's rules allowing drivers to unionize.



Uber subsidiary Riser filed a lawsuit in King County Court asking a judge to review the rules and then find them invalid.



Uber says they're "arbitrary and capricious."



When the City Council approved the rules in 2015, it acknowledged they could face a court challenge. The city issued a draft of the unionization plan in November.



The measure requires companies that hire or contract with drivers of taxis, for-hire transportation companies and app-based ride-hailing services to bargain with their drivers if a majority wants to be represented.



Seattle was the first city in the U.S. to establish such rules. The lawsuit claims the city didn't provide comprehensive rules.



The U.S. Chamber of Commerce sued over the rules in March 2016, but that suit was dismissed.