As if the process of car buying didn’t cause enough headaches, they don’t end after you’ve handed over your money and paperwork. You still have to register it, or else you won’t get a license plate. For some, this is just another step to check off. But for others, it’s an opportunity to get a personalized license plate number. However, with how many cars there are on the road, is it possible for someone in another state to share your license plate number?

Each state has its own license plate number rules and laws

New York State issued the first US license plate in 1901, Motor Trend reports. Since then, each state has established its own plate program. And they’ve only grown in complexity over time. It wasn’t until 1956 that the size itself was standardized, Automobile reports. Plus, states used to issue new plates every year, Autoweek reports. And even today, some states offer hundreds of possible plate designs, NCSL reports.

As such, there’s no one common rule amongst how states number their license plates. A few plates use 6 alphanumeric characters, while others use 7. Some states separate the characters into two groups, while others don’t. Some states’ license plate numbers start with letters, not actual numbers. And sometimes, the order is randomized, too, not just the characters, Arizona’s DOT reports.

But how are the license plate numbers themselves assigned? Again, that differs from state to state. Some states go in ascending order, e.g. first ABC 1234 then ABC 1235, and so on. Others go in descending order. As for the numbers themselves, sometimes they’re based on where the car is registered, Serra Toyota reports. But in some states, they’re genuinely randomized.

And that last part comes with a slight risk of chaos.

Your license plate number isn’t necessarily unique

The 7 characters on your license plate aren’t necessarily the only part of its designation. For example, in Illinois, where I live, EVs have ‘EL’ printed on their plates. And there are specific designations for heavy-duty trucks, antique vehicles, and cars with tinted windows.

Plus, some states have prohibitions on certain symbols, word, and letter combinations. In Minnesota, for example, only certain vehicles can use W, Y, and Z, the StarTribune reports. And of course, you can’t use put vulgar messages on your personalized or vanity plates.

However, because each US license plate number has a maximum of 7 characters, as opposed to the EU’s 8, there are fewer allowable combinations, Autoweek explains. Using Minnesota as an example, the plate uses 10 numbers and 23 letters. The state currently uses the 123 ABC format, meaning there are 12,167,000 unique combinations.

To be fair, that sounds like a lot. However, every other state has at least that many allowable combinations, too. And while there is a national database of plate information, Road & Track reports, each state’s registration process is separate. So, it’s entirely possible for two different cars in two different states to have the same license plate number.

Such a situation isn’t just hypothetical. For example, in 2017, one Rhode Island resident received numerous unpaid toll invoices for a New York-registered vehicle, NBC10 reports. Why? The NY truck had the same combination of letters and numbers as the Rhode Island-registered car.

My family member was recently in a similar situation. A truck passed through a tollway without paying, and the camera snapped a photo of the plate. That plate number belongs to my family member. However, the photographed plate was really from out of state. It just had the same number combination.

Is this something worth worrying about?

Admittedly, the odds of this happening are fairly slim. Going back to the Minnesota example, the odds of another 6-digit plate matching up are 1 in 148,035,889,000,000.

Plus, in my family member’s case, it was an issue with the camera not detecting the issuing state. It took a real person looking at the photo to do so. The same issue affected the Rhode Island resident. As camera technology improves, the frequency of these incidents will likely decrease.

Applying for a personalized license plate is one potential way around this. However, unless you really want it, it’s not strictly necessary.

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