A former San Diego Uber driver sued Uber Monday, alleging the company's use of a passenger rating system in driver evaluations leads to racial bias and discrimination, NPR reports.

Filed in San Francisco, the lawsuit claims that the star rating system passenger's use creates racial bias against drivers who aren't white or who speak with accents. Once a driver's average rating drops below a certain number, the driver is fired, the suit argues.

The lawsuit seeks class action status and aims to include all minority Uber drivers. Additionally, the lawsuit asks the court to prohibit Uber from using passenger ratings in determining whether or not to ban a driver.

"Uber has long known that relying on a system that depends on passenger evaluation of drivers is discriminatory," lead attorney Shannon Liss-Riordan wrote in the federal lawsuit.

In a statement to NPR, an Uber spokesperson refuted the claims, arguing that "ridesharing has greatly reduced bias for both drivers and riders, who now have fairer, more equitable access to work and transportation than ever before."