SEATTLE – Seattle has become the first city in the nation to allow drivers of ride-hailing companies such as Uber and Lyft to unionize over pay and working conditions.

The legislation the City Council approved Monday is seen as a test case for the changing 21st century workforce. The companies strongly oppose it and are expected to challenge it in court.

The council passed the measure on an 8-0 vote. It requires companies that hire or contract with drivers of taxis, for-hire transportation companies and app-based ride-hailing services to bargain with its drivers, if a majority show they want to be represented.

San Francisco-based Uber and others argued federal labor law prevents cities from regulating collective bargaining for independent contractors, and the ordinance would violate federal antitrust laws.

Supporters say many drivers are immigrants who depend on full-time work, but some make less than minimum wage and lack basic worker rights.

Uber and others say federal labor law prevents cities from regulating collective bargaining for independent contractors. They say the ordinance would violate federal antitrust laws by allowing independent transportation providers to conspire to artificially drive up transportation costs.