...AND CHEAPER...:

Walmart said Monday it has started using fully driverless trucking in its online grocery business, aiming to increase capacity and reduce inefficiencies.

Walmart and Silicon Valley start-up Gatik said that, since August, they've operated two autonomous box trucks -- without a safety driver -- on a 7-mile loop daily for 12 hours. The Gatik trucks are loaded with online grocery orders from a Walmart fulfillment center called a "dark store." The orders are then taken to a nearby Walmart Neighborhood Market grocery store in Bentonville, Arkansas, where Walmart is headquartered.

It'll be two or three years before autonomous trucks are ready for commercial deployment on U.S. highways. But the first data-driven studies from early pilot programs suggest they'll be substantially more efficient.

TuSimple and UPS, for example, say their self-driving test trucks achieved 13% fuel savings while racking up 160,000 autonomous highway miles in Arizona.

"To get 13% fuel savings is unheard of," TuSimple CEO Cheng Lu tells Axios -- worth billions of dollars for the U.S. trucking industry.

Fuel accounts for 24% of the cost per mile for heavy-duty trucks, second to labor, at 42%, per the American Transportation Research Institute.

TuSimple's system drives more smoothly and efficiently than a human driver, Lu explains. "How you operate the truck has a very big impact on fuel economy. It's a great validation of the maturity of our technology."

Another study by Georgia Tech found that Ryder Systems' new autonomous transfer hub networks -- combining self-driving trucks on highways with conventional trucking operations for the first and last miles -- could save shippers up to 40%.

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