In an effort to improve efficiency, UPS has been quietly utilizing self-driving vehicles to transport cargo over the last few months. The delivery company confirmed the move Friday, when it announced it taken a minority stake in the autonomous driving startup TuSimple.

According to a press release, UPS has been working with TuSimple to "better understand the requirements for Level 4 Autonomous trucking in its network." Level 4 refers to a vehicle that is controlled by a computer the entire time, which effectively eliminates the need for manual operations. According to Forbes, the trailers UPS has been using are equipped with digital cameras, radar, and LiDAR, sensors; however, UPS states that a driver and an engineer have been on board to monitor the operations, as required by law. 

"UPS is committed to developing and deploying technologies that enable us to operate our global logistics network more efficiently," Scott Price, UPS' chief strategy and transformation officer, said in a press release. "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."

TuSimple says its mission is to "increase safety, decrease transportation costs, and reduce carbon emissions" through self-driving technology. The company also states that UPS' newly announced investment will cut the average cost of shipping with a tractor-trailer by 30 percent.

Back in May, the United States Postal Service announced it had partnered with TuSimple for a two-week pilot program that consisted of five round trips between Phoenix and Dallas. According to Electronic Design, the test run was deemed a success, as all deliveries were completed ahead of schedule without any traffic incidents.