Domino's will begin delivering pizza using self-driving robots in the Houston area later this year, the company announced on Monday. The company will use delivery vehicles from the Silicon Valley startup Nuro.

“Nuro’s vehicles are specially designed to optimize the food delivery experience, which makes them a valuable partner in our autonomous vehicle journey," said Kevin Vasconi of Domino's in a press release. "The opportunity to bring our customers the choice of an unmanned delivery experience, and our operators an additional delivery solution during a busy store rush, is an important part of our autonomous vehicle testing.”

The deal is a coup for Nuro, which raised $940 million in February and is already delivering groceries for Kroger in the Houston area. Pizza delivery is one of the most common applications for last-mile deliveries, and Domino's is one of the biggest companies in the business, delivering about 3 million pizzas per day. That's a lot of potential business for Nuro if the Houston trial is successful.

"Select customers who order online from one of Domino’s participating stores will have the opportunity to use Nuro’s autonomous delivery," according to the press release. "Once they have opted in, customers can track the vehicle via the Domino’s app and will be provided with a unique PIN code to unlock the compartment to get their pizza."

Nuro's custom vehicle is optimized for deliveries

Most companies developing self-driving technology have either focused on autonomous passenger cars or long-distance trucking. Nuro, along with competitors like Udelv and Robomart, have focused on last-mile product delivery instead.

Nuro has a custom-built delivery vehicle called the R1. It's about half the length and width of a conventional passenger car and doesn't have any space inside for a driver.

The small size has safety benefits. The vehicle only takes up about half the lane width, giving Nuro room to swerve if a child or pet darts out into the street. It's much lighter than a conventional car, reducing the chances of serious injuries if it were to hit someone.

Nuro doesn't have to worry about its cargo getting annoyed by a slow ride, so its cars stick to low speeds—currently under 25 miles per hour—to minimize the chances of a serious accident. With no need to worry about passenger comfort, Nuro's cars can slam on the brakes the moment they encounter a situation they don't fully understand.

Most self-driving companies try to make the problem easier by geofencing the areas where their vehicles operate. This is awkward for a taxi service, since human passengers frequently want to travel outside arbitrary geographic boundaries. But it's natural for last-mile delivery services, since these services always operate in a limited area around a physical store or warehouse.

While there's no one inside the vehicle, Nuro still has each delivery vehicle followed by a human-driven car. Inside is an operator monitoring the delivery vehicle and able to take over in an instant if anything goes wrong. Nuro CEO Dave Ferguson told me in February that the company was hoping to stop using the chase cars by the second quarter of 2019—a step that will be required for the company to scale up rapidly. However, a Nuro spokesman told me today that the company will continue using chase cars "for now."