SAN FRANCISCO (Reuters) - Lyft has completed more than 5,000 self-driving rides through its ride-hailing app, the company said on Tuesday, as it aims to become a serious competitor in autonomous driving while its biggest rival, Uber, retrenches.

Lyft launched its self-driving service in January in Las Vegas, where passengers can take a ride in an autonomous BMW to and from some 20 different pick-up and destination spots around the city's casino-laden Strip. The autonomous driving system is not built by Lyft, however, but by high-tech auto-parts supplier Aptiv Plc APTV.N, which Lyft partnered with earlier this year.

Lyft is developing its own self-driving system, but company officials have declined to say when it will be ready for public streets. Lyft is far behind competitors such as Alphabet Inc's GOOGL.O Waymo, which has been testing autonomous cars for about a decade.

The Las Vegas service is available to all Lyft passengers, who get a prompt asking if they agree to ride in a self-driving car. If their destination is along one of the approved routes, they may get picked up by a robot car. Two safety drivers are in the front seats.

Lyft and Aptiv declined to provide financial details on the service, which costs passengers the same as a Lyft ride in a human-driven car, but both companies “are making money on this,” said Jody Kelman, product lead for Lyft’s self-driving platform.

Aptiv has a fleet of 75 self-driving cars in Las Vegas, 20 of which are picking up Lyft passengers. The company is a spin-off of Delphi Automotive Plc, which last year acquired self-driving startup NuTonomy, which is also testing self-driving cars in Singapore and Boston. Aptiv and NuTonomy are working to integrate their systems.

Lyft has several partnerships in the self-driving space, but the deal with Aptiv is the only one so far to result in rides for the public. Lyft was late to self-driving cars, announcing just more than a year ago plans for an autonomous driving development center in Silicon Valley.

Lyft’s chief rival, Uber Technologies Inc [UBER.UL], has meanwhile retrenched from its self-driving ambitions. Following a fatal accident in March in Arizona, in which an Uber SUV operating in self-driving mode killed a pedestrian, Uber suspended its self-driving testing and shuttered its operations in Arizona, its chief testing ground.

Uber has not yet reintroduced its self-driving cars in Pittsburgh, Pennsylvania, as it said it would by this summer. And last month, Uber ended its work on self-driving trucks.