The United States Postal Service (USPS) has chosen self-driving trucking company TuSimple to haul mail as part of a two-week test of the startup’s autonomous technology. TuSimple will carry the mail on five round trips between the USPS’s Phoenix, Arizona, and Dallas, Texas, distribution centers, which is a stretch of more than 1,000 miles.

The test runs will include overnight driving, and TuSimple’s trucks will have both a safety driver and engineer on board. The USPS has also been running a years-long competition to create an all-electric version of its next-generation mail delivery truck.

TuSimple has been slowly expanding its testing over the last year, starting largely in the autonomous testbed that is Arizona, where it had 11 trucks on the road as of January. While it hasn’t named names, the startup has carried cargo for 12 different companies on its tests to date as a way to offset the cost of developing its self-driving technology. The USPS deal will mark the company’s first time testing in Texas.

TuSimple is backed by Nvidia and Chinese tech company Sina

Founded in 2015, TuSimple has raised $178 million to date, with Nvidia and Chinese technology company Sina as its most notable backers. The startup has two headquarters, one in San Diego, California, and another in Beijing.

TuSimple uses Navistar trucks outfitted with the startup’s own self-driving tech, which relies heavily on nine cameras. The trucks each have a pair of LIDAR sensors on board, but much like Tesla CEO Elon Musk, the startup is focused on developing a vision-based autonomous system.

Founder Xiaodi Hou spoke to The Verge at this year’s Consumer Electronics Show about why he wants to create a fully autonomous big rig over a so-called “Level 2” driver assistance system where the human is still ultimately in control of the vehicle, something Daimler is currently developing for its own trucks.

“Beating Mobileye will be the holy grail for all of the Level 2 systems,” Hou said, referring to the Intel-owned Israeli firm that helped develop the first version of Tesla’s Autopilot. “But I’m jumping out of this Level 2 war, I’m starting a new frontier. I just don’t want to repeat what they have done.”

Developing a self-driving truck that can operate without a human, Hou said, is a “problem that is so hardcore.” Still, he said he believes people are underestimating the progress of autonomous vehicles, especially in specific settings like trucking where he believes it’s possible to start doing business while development is happening. Hou estimated that making deliveries while testing means TuSimple’s cost per mile is “probably 10 percent or lower” than that of robotaxi companies like Waymo. “As long as those eggs in the back are not broken, you should pay me my shipping fee,” he said.