Since late December, San Diego autonomous driving outfit TuSimple has run seven semi-truck trips between Tucson and Phoenix without a driver in the vehicle.

These driver-out demonstrations aim to prove that TuSimple’s artificial intelligence autonomous driving technology works repeatedly along a real freight hauling route.

And this spring, the recently public company hopes to add another layer of proof by delivering actual freight for Union Pacific — one of the nation’s largest railroad shippers.

While not groundbreaking by itself, the deal with Union Pacific announced Wednesday aims to provide additional evidence that TuSimple’s technology can add value to the freight hauling industry in real-world conditions…

TuSimple will own and operate the 53-foot big rig making the roughly 80-mile trip between the Tucson railyard and a distribution site near Phoenix using open, public roads without a human in the vehicle.