Kicking off today, the pilot will see TuSimple's self-driving trucks used to haul mail between USPS's distribution centers in Phoenix, Arizona and Dallas, Texas. This route, which stretches over more than 1,000 miles (1,600 km) and crosses state lines will be covered five times as round trips, with TuSimple's trucks hauling USPS trailers along for the ride.

Like others in the business of delivering goods, such as UPS and DHL, the USPS is exploring how autonomous vehicles can streamline its operations, cut down on fuel costs and pollution, as well as improve safety. This is particularly pertinent when it comes to long-haul routes with short turnaround times, which require a lot of human drivers.

And the agreement is significant for TuSimple, too, which has until now been validating its autonomous technologies with shorter trips for customers in Arizona. Human operators are onboard throughout to gather data and ensure safety, and the same goes for the new two-week trial with USPS as its expands its operations into Texas.

"It is exciting to think that before many people will ride in a robo-taxi, their mail and packages may be carried in a self-driving truck," said Dr. Xiaodi Hou, Founder, President and Chief Technology Officer, TuSimple. "Performing for the USPS on this pilot in this particular commercial corridor gives us specific use cases to help us validate our system, and expedite the technological development and commercialization progress."