A lawsuit against the Philadelphia Parking Authority filed by the city's taxi companies over the PPA's alleged failure to regulate competitors Uber and Lyft can move forward, a federal judge in Pennsylvania has ruled.

U.S. District Judge Michael Baylson of the Eastern District of Pennsylvania denied the PPA's motion to dismiss cab companies' equal protection clause claims alleging ride-hailing services were allowed to operate under the radar when it came to enforcement.

The ruling is the latest chapter in a host of litigation both in Philadelphia and around the country involving cab companies suing over what they allege are ride-hailing companies. However, the case itself is unique in that the taxi operators aren't targeting the ride-hailing companies, but the regulatory body that oversees point-to-point transportation.