BENTONVILLE, Ark. — Walmart is expanding its tests of driverless vehicles via a program to use Udelv autonomous-driving vans to deliver groceries in Surprise, Ariz.

“We want to make sure we stay on the cutting edge of grocery delivery by exploring what’s new and next,” Tom Ward, senior vice president of digital operations for Walmart U.S., wrote Tuesday in a post on the company’s blog.

“What’s really cool is that Udelv will utilize a cargo van custom-made to deliver fresh groceries,” Ward said.

The pilot is the company’s latest experiment in finding an efficient way to get merchandise to shoppers who order groceries on Walmart’s website or through its app.

Walmart has well-honed capabilities for in-store pickup of digital orders, and the company has touted the advantages of the program over the more costly delivery option. But analysts see delivery capabilities as a vital component of any strategy to compete for what’s expected to be a surge in digital spending on groceries by consumers.

Walmart’s previously announced pilots of grocery delivery programs include test of autonomous-driving vehicles with self-driving vehicle companies Ford and Waymo.

Other tests have involved use of employees to deliver merchandise during their off-duty hours, and a program called Spark Delivery, a crowd-sourced alternative with a partner, named Brinng, that recruits drivers in Uber fashion for individual grocery deliveries.

In an interview on CNBC last month, Marc Lore, president and chief executive officer of Walmart eCommerce U.S., said the future of food delivery could be as convenient as “delivery right into the fridge.”

Walmart expects that when its fiscal year concludes, at the end of this month, it will have an online grocery delivery option in about 100 metropolitan areas, reaching more than 40% of U.S. households, with more to come.