California is beginning a trial of digital number plates in a bid to ease the process of registering cars and changing registrations. 

The plates are a $699 (around £526/ Rs 47,158) option from dealerships and can display customised messages by the user, as well as advertisements and traffic information. When this mode is enabled, the car’s number is displayed in the top corner, according to a report in the Sacramento Bee. This mode is only available when the car is parked, however.

There is a monthly service charge of $7 (around £5.26/ Rs 472), as well as the cost of registering the car in the first place — it's $83 (around £62.50/ Rs 5,597) in California. An additional installation fee may also be charged.

The plate, which is equipped with a tracker, can register trip data and log traffic conditions and could help in recovering stolen vehicles, providing that the plates aren’t removed when the car is stolen. 

Legally, the trial can only be offered to 0.5 percent of vehicles across the state, equating to 175,000. The city of Sacramento has ordered 24 plates to use for the trial and has assured union representatives that they will not be used to track drivers. 

The trial is one of the more conventional ideas to feature digital displays on cars; past proposals have included emoji message boards on the front of autonomous cars, as well as a driverless car that can display a smiley face when encouraging pedestrians to cross in front of it. 

There are no reports as yet as to when the rest of the world is going to receive this technology.

Also read: The autonomous car that smiles at pedestrians