As the food service industry struggles to find workers, Domino’s has deployed a unique strategy to fulfill orders: robot delivery vans.

The company has begun making autonomous deliveries in Houston, using self-driving vehicles that pull up to your driveway. The program was first announced two years ago, but only began making real-world deliveries on Monday.

The autonomous deliveries, powered by Nuro’s R2 robot, are being made in the Woodland Heights area of Houston. Customers can choose whether they want a robot or not.

Those who choose robot delivery will be able to track the vehicle (and their pizza) via GPS on their order confirmation page. When the vehicle pulls up, customers simply enter a PIN to open the doors and allow them to retrieve their food.

Tipping is optional—and superfluous.

"We're excited to continue innovating the delivery experience for Domino's customers by testing autonomous delivery with Nuro in Houston," said Dennis Maloney, Domino's senior vice president and chief innovation officer in a statement. "There is still so much for our brand to learn about the autonomous delivery space. This program will allow us to better understand how customers respond to the deliveries, how they interact with the robot and how it affects store operations."

The R2 is the first completely self-driving, on-road delivery vehicle to get regulatory approval from the Department of Transportation. That was given last February. Besides the vehicle’s work with Domino’s, it also partners with Walmart and Kroger in the Houston area for deliveries.