Zoox Inc., a secretive autonomous-driving startup in Silicon Valley, is seeking to raise as much as $252 million in funding, according to a securities filing. While Zoox has said very little about what it’s working on, it’s the only startup with alicense to operate autonomous vehicles on the road in California. The other startup that had a similar license was Cruise Automation, which General Motors Co. acquired in March.

California has also granted permits to Google parent Alphabet Inc., Ford Motor Co., Tesla Motors Inc. and about a half-dozen other companies. Uber Technologies Inc. has started testing self-driving cars in Pittsburgh, where it collaborates with the robotics group at Carnegie Mellon University.