SAN FRANCISCO: Apple has joined the list of companies with permits to test self-driving cars in California, according to an updated roster released on Friday (Saturday in Manila) by state officials. The iPhone maker has disclosed little about its ambitions when it comes to self-driving vehicles, with chief Tim Cook hinting at plans but the company declining to comment for news reports on long-idling rumors. Late last year, Apple revealed it is investing heavily in autonomous vehicles in a letter asking the government to make it easier to develop self-driving cars. The California-based tech giant is expected to focus on software systems, letting partners manufacture vehicles, but would understandably want to be able to test its navigation technology in cars. Most major auto manufacturers and many technology groups are currently developing autonomous vehicles, considered to be the future of the automobile, along with electric power, with first production models promised for around 2020.