Waymo has announced a new partnership with DoorDash that will make the company's self-driving cars a delivery option for users in Phoenix, Arizona. You can already hail a ride in Waymo's Arizona service area, but this new partnership will give the company's cars something to do when they're not transporting human cargo.To start, Waymo says that deliveries will be limited to things you can order through DashMart, DoorDash's storefront for convenience and grocery stores. Eventually, though, deliveries will "include more local Phoenix merchants and a wider variety of offerings."