California is testing a digital display license plate that allows changeable messages controlled by the driver or remotely by fleet managers.
The new plates use the same computer technology as Kindle eBook readers, along with a wireless communication system, the Sacramento Bee reports.
They come with their own computer chips and battery.
If the car is stolen, the plate's manufacturer says the plate can tell the owner and police exactly where the car is or at least where the license plate is if it has been detached.
Last week, Sacramento became the first city to agree to test the plates, taking a shipment of 24 plates for its in-house vehicle fleet.
Dealerships are expected to sell the plates for $699, not including installation costs. Users also must pay a monthly fee of about $7. The plates are not available through the DMV.