Phoenix will, yet again, be a testing ground for self-driving vehicles. This time, it's for UPS and its partnership with Waymo in a plan announced Wednesday.

Autonomous Chrysler Pacifica minivans with the Waymo brand will pick up packages in metro Phoenix — the same area where its self-driving vehicles already operate. The minivans will take packages from UPS store locations to a local UPS sorting facility for processing - and won’t involve package delivery to consumers.

And it won't be entirely automated. The vehicles in this pilot will have a Waymo-trained driver on board to monitor autonomous operations.

Previously, UPS partnered with autonomous trucking company TuSimple between Phoenix and El Paso, Texas. The company said it is modifying some of its minivans for package delivery by removing the back seats.

Waymo has more than 600 self-driving vehicles in its fleet, mostly housed in Arizona.