TuSimple, which began autonomous semi runs “driver out” with no human in the cab last year, says freight rail giant Union Pacific will be the first customer to use its automated trucking service to haul cargo in Arizona.

From this spring TuSimple trucks will pick up loads at a Union Pacific freight depot in Tucson and haul them to a distribution center in Phoenix. Though the deal is non-exclusive it is a significant new partnership for San Diego-based TuSimple, CFO Pat Dillon tells Forbes.