It is illegal for a civilian to run someone’s license plate number for personal reasons.
The Police and the Department of Motor Vehicle (DMV) are the only ones legally allowed
to trace a license plate. However, you can still have limited access to some information
in the following circumstances:
You have legal authorization or written consent from the vehicle’s owner.
You work for a security service or you are a licensed investigator.
For issues of motor vehicle and public safety.
Notice for impounded towed or vehicles, emissions, theft, product recalls.
Unless you are a government official or a police officer you cannot get full legal access
to someone’s personal information just by looking up their license plate.