By Jackie Wattles

NEW YORK (CNNMoney) -- Walmart is planning to eventually have self-driving shopping carts roaming its stores and herding themselves out of the parking lot.

The U.S. government granted Walmart a patent last week that indicates the company is planning to roll out a system that allows shopping carts to drive themselves.

According to the patent request, the carts will be equipped with detachable motors that have sensors and video cameras. Customers will be able to request a cart using a "user interface device" -- potentially a smartphone -- and the roaming motors will be able to fetch a cart and bring it to a customer.

And employees who are usually in charge of rounding up abandoned carts may be able to abandon that task. The system will, in theory, be able to identify an unattended shopping cart in a store or parking lot and return it to a docking station, according to the filing.

The system may help the stores manage inventory. One portion of the filing describes a scenario in which the system receives a request for an item, searches an inventory database, then sends the motorized unit to a store shelf to ensure the product is there.

There's no word yet on when or where Walmart intends to start using the system. A Walmart spokesperson was not able to immediately provide additional information.

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