Uber loses bid to block drivers from suing as group for tips

"Uber's uniform and unilateral right to control its drivers' compensation is important common proof that bears directly on the class members' work status," Chen wrote.

Chen allowed the plaintiffs to pursue reimbursement for expenses including mileage by filing further arguments within 35 days. Liss-Riordan said she will pursue those claims.

'California law'

Chen's ruling "will very much impact other jurisdictions even though the case is California law," said Orly Lobel, a law professor at the University of San Diego who specializes in labor and employment issues.

In lawsuits challenging whether workers are independent contractors or employees, all U.S. courts, state and federal, use a similar test to weigh the "economic reality" of the position, and whether the worker is controlled by the employer in the sense of being hired and fired, or directed throughout the job, Lobel said.

Whether an individual is classified as an independent contractor or an employee can affect benefits, and an employer's employee counts, under many different state and federal laws, including the Patient Protection and Affordable Care Act (PPACA) and the federal Family and Medical Leave Act (FMLA). 

See also: Federal agencies pan PPACA employee counting rules

"The question of whether Uber drivers are employees will be determined by the very specific context and the particular circumstances of their relationship with Uber, and once one judge decides about their status this will be very influential for other judges," Lobel said.

Uber argued that the vast majority of its drivers prize their status as independent contractors permitting them to work whenever and as often as they like. Uber has said it relies on as many as 17 different licensing agreements for drivers, which the company argued is typical of independent contractor relationships.

See also: Could insurance go "Uber?"

Chen rejected Uber's argument, writing that Uber's right to terminate its drivers, described in the licensing agreements, further demonstrates Uber's control over its drivers and "weighs heavily in favor of class certification."

The case is O'Connor v. Uber Technologies Inc., 13-cv-03826, U.S. District Court, Northern District of California (San Francisco).

—With assistance from Eric Newcomer in San Francisco.