Uber's self-driving trucks have officially hit the road and are delivering cargo in Arizona.

In a release Tuesday, the company announced its trucks were hauling real loads across the Grand Canyon State through Uber Freight, an app that connects companies and their drivers with shippers.

According to USA Today, Uber's Volvo trucks have been sent on delivery runs in Arizona since November.

"This a big step forward in self-driving truck technology, and the future of the freight industry at large," the company said in a release Tuesday.

In the latest haul outlined in a release from Uber, a load was moved along I-40 between Sanders, Arizona and Topock, Arizona and eventually onto Southern California. But it wasn't all via self-driving trucks. Uber's pilot program doesn't actually feature these trucks making the full run from pick-up to delivery.

Instead, like in this most recent delivery, Uber uses both self-driving and human-driven trucks. Uber's self-driving trucks focus on the "long haul, highway" part of the delivery.

Here's how it works:

After a shipper submits a load via the Uber Freight network, a driver, in a conventional truck, picks up the load. That driver will take the load from the shipper to a transfer hub where it's handed off to a self-driving truck.

The self-driving truck does the heavy lifting or longest drive (with a vehicle operator in the driver’s seat) and takes the load to a second transfer hub. There, it's given to another conventional truck for the short haul to the load's final destination.

The idea, according to USA Today, is that "truckers get to go home to their families instead of being on the road."

"The big step for us recently is that we can plan to haul goods in both directions, using Uber Freight to coordinate load pickups and dropoffs with local truckers," said Alden Woodrow, Uber's self- driving truck program lead, told USA Today. "Keeping trucking local allows these drivers to make money while staying closer to home."