Apple has expanded its fleet of self-driving cars in California, registering an additional two dozen vehicles with the state’s Department of Motor Vehicles. It’s a significant expansion for a company that has been seen as lagging in the race to build self-driving cars.

Apple originally registered three Lexus Rx450h SUVs under its permit to test autonomous vehicles in April 2017. Since then, it has acquired an additional 24 Lexus SUVs, according to the DMV, two in July, seven in October, two in November, six in December, and seven in January.

The news was first reported by Bloomberg.

Unlike companies like Waymo (Google subsidiary) and Uber, Apple has been tight-lipped about its self-driving car program, codenamed Project Titan. Last July, CEO Tim Cook confirmed in an interview that the iPhone maker is currently “focusing on autonomous systems”, rather than, say, a car stamped with the Apple logo and that this could be used for many different purposes.

Apple’s test vehicles have been spotted a couple of times in the wild, most recently last October. The car appeared to be outfitted with standard third-party sensors and hardware, including (count ‘em) six Velodyne-made LIDAR sensors, several radar units, and a number of cameras — all encased in Apple-esque white plastic.

But Apple has a lot of catching up to do if it’s going to be a player in the self-driving car space. The company ranked second-to-last in Navigant Research’s most recent leaderboard analysis of the autonomous vehicle race, right ahead of Tesla.