The patent, for an “autonomous delivery platform,” describes using self-driving trucks to deliver packages to specific destinations. Inside the truck, individual lockers will each contain one package (or perhaps multiple ones if they’re meant for the same recipient) and they can only be unlocked by entering a password on a keypad-like interface. The documents also mentions that the lockers could be equipped with payment processing technology so that a recipient can only open it after paying via credit card or via near-field communication technology.

Though the patent doesn’t describe in too much detail the self-driving car technology itself, Google is well-known for its efforts in that area. The company has been working on self-driving cars since 2009, and plans to get them on the road by 2020.

And, as Quartz notes, Google (GOOGL) is also working on delivering packages via drones, so this latest patent is far from surprising, regardless of whether it does eventually put self-driving trucks on the road.

Google is of course not the only company showing interest in driverless cars and their use for delivery. Ride-hailing company, and aspiring logistics provider, Uber has been heavily investing in driverless car technology. Amazon (AMZN) also joined the group recently when it announced a partnership with Ford Motors, which is developing its own driverless cars, that would let customers control their cars via Amazon’s virtual assistant, the Echo.