TuSimple, which has been testing its self-driving trucks in Arizona for more than a year, said it would expand its Tucson center on Sept 12, creating 500 new jobs in a variety of fields ranging from engineering and autonomous truck driving to office management. TuSimple also will expand its autonomous fleet to 200 trucks in the US by 2019. With 500 trucks worldwide next year, TuSimple will possess the world's largest autonomous truck fleet. "We work with Peterbilt trucks hauling commercial cargo primarily in Arizona, and we are generating some revenue," company spokesman Robert Brown said in an interview. While utilizing TuSimple's self-driving system, Brown said the trucks in the test fleet have a driver and test engineer on board to monitor the rig.