UPS has been delivering packages for months in self-driving trucks, and no one knew.
The company just announced they made a minority investment in TuSimple, the self-driving freight truck startup that has been delivering mail across Arizona for the last few weeks.
But TuSimple self-driving trucks have also been transporting UPS loads between Phoenix and Tucson since May, the company revealed.
TuSimple cuts the shipping cost in a tractor-trailer by 30 percent, the company claims.
USPS also has done a two-week pilot program with TuSimple between Phoenix and Dallas.