Identifying someone via license plate lookup
In the event that you ever need to identify a car or individual by license plate number alone, you're in luck. People search services are more prevalent online than ever before, and can help you find someone via name, license plate number, phone number, or address. Be wary, as many of these are disreputable, forcing the user into a subscription or other recurring fees, or supplying outdated information. License plate search is definitely possible these days but read on before you take any action.
More reputable information, however, will most likely be found through the states themselves, or services the state may have partnered with. As of now, a number of states allow paid access to DMV records, get license plate information, through organizations such as TransUnion TLO. Most if not all others have forms, such as California's Request for Record Information form INF 70, which can be used to obtain an individual's driver's license, identification, or vehicle registration information.
In closing, while it's easier than ever to find a service offering license plate lookup, the old adage holds true: If you want it done right, do it yourself.