Kroger kicked off a pilot program in Phoenix, Arizona this week using autonomous Toyota Priuses to deliver groceries, the Associated Press reports.

The details: The project allows customers to order same-day or next-day delivery "for a flat rate of about $6." The vehicle will be loaded with groceries at the Kroger store and drive to the shopper's house, where the customer will need to unload it themselves. According to the AP, customers will be able to open the vehicle with a numerical code.

Kroger partnered with Silicon Valley startup Nuro, which was founded by two former engineers that worked on Google's autonomous vehicles team, Waymo, to run the pilot program.

which was founded by two former engineers that worked on Google's autonomous vehicles team, Waymo, to run the pilot program. Nuro co-founder Dave Ferguson told the AP: "Our goal is to save people time, while operating safely and learning how we can further improve the experience."

The backdrop: Kroger's test follows a similar self-driving project headed by Walmart, which recently partnered with Waymo to shuttle shoppers to stores to pick up online grocery orders.