Uber Technolgies Inc [UBER.UL] on Friday again defied a demand by California regulators that the ride-services firm apply for a permit to test self-driving cars, setting up a possible legal battle. Uber said its self-driving cars, unveiled to the public on Wednesday, would remain on the road, and reiterated its defiance of an order from the California Department of Motor Vehicles to "cease" operations. "We respectfully disagree with the California Department of Motor Vehicles legal interpretation of today's autonomous regulations," Anthony Levandowski, vice president of Uber's Advanced Technologies Group, said on a call with reporters.