The big-box retailer has been working with a startup called Gatik on a delivery pilot for 18 months. Gatik, which is based in Palo Alto and Toronto, outfitted several multitemperature box trucks with sensors and software to enable autonomous driving.

Since last year, those trucks have been operating on a two-mile route between a "dark store" (a store that stocks items for fulfilment but isn't open to the public) and a nearby Neighbourhood Market in Bentonville, Arkansas. Since then, the vehicles have racked up 70,000 miles in autonomous mode with a safety driver.

Next year, the companies intend to start incorporating fully autonomous trucks into those deliveries. And they plan on expanding to a second location in Louisiana, where trucks with safety drivers will begin delivering items from a "live" Walmart

Supercentre to a designated pickup location where customers can retrieve their orders.

Those routes, which will begin next year, will be longer than the Arkansas operation -- 20-miles between New Orleans and Metairie, Louisiana.