ATLANTA, Ga. –UPS Ventures, the venture-capital arm of courier giant United Parcel Services, has acquired a minority stake in the self-driving startup TuSimple.

Together, both companies are testing self-driving tractor-trailers on a route in Arizona to determine whether the vehicles can improve service and efficiency in the UPS network, UPS said Thursday.

“This is an extension of the ongoing commercial relationship between UPS and TuSimple in which UPS has purchased transportation services from TuSimple.”

The work with TuSimple began with the goal of helping UPS better understand the requirements for Level 4 Autonomous trucking in its network, the company said.

“L4 Autonomous means the vehicle’s onboard computer is in complete control at all times, eliminating manual intervention. Currently, however, laws regulating L4 Autonomous driving require a driver in the vehicle at all times to take over operation if needed,” UPS said.

Throughout the ongoing tests, UPS has been providing truckloads of goods for TuSimple to carry on a route between Phoenix and Tucson, Ariz.

The company initiated self-driving service in May, 2019, with a driver and engineer in the vehicle. TuSimple and UPS monitor distance and time the trucks travel autonomously.

“While fully autonomous, driverless vehicles still have development and regulatory work ahead, we are excited by the advances in braking and other technologies that companies like TuSimple are mastering,” said Scott Price, chief strategy and transformation officer at UPS.

“All of these technologies offer significant safety and other benefits that will be realized long before the full vision of autonomous vehicles is brought to fruition – and UPS will be there, as a leader implementing these new technologies in our fleet.”

UPS’s tests with TuSimple are part of an advanced technology evaluation for vehicles in the UPS Global Smart Logistics Network, the company said.

“We are honored by UPS’s strategic investment and their vote of confidence in TuSimple, this proves their commitment to staying at the forefront of innovation,” said Xiaodi Hou, founder, president and CTO of TuSimple.

“TuSimple is confident that it can accelerate bringing the first self-driving truck to market to increase road safety.”

The company believes it could cut average purchased transportation costs by 30%.