# Wisconsin’s license plates are tapped out

It’s the end of an era on Wisconsin’s license plates.

There are no more six-character combinations left in America’s Dairyland.

The state will go to seven, the Division of Motor Vehicles announced today.

Six characters can provide 20-million variations, which took from 1986 to exhaust. Adding the seventh character will provide 100 million.

If you’ve done the math on that and find it doesn’t work out, it’s because I, O and Q are not used on license plates because they’re too similar to numbers.

• MrE85

“It’s the end of an era on Wisconsin’s license plates…”
I think we’ll all remember where we were and what we were doing when we learned of this change. 😉

• Jerry

And the letters and numbers have to stick together in blocks? In the old way, I take it we could have done things like ABC123 or 123ABC. That gives 2*23^3*10^3=24,334,000. So you’re saying that now they allow things like ABC1234 and 1234ABC? Then I think there should be 2*23^3*10^4 = 243,340,000 combinations. Or is 1234ABC not allowed? That would bring us back down to 23^3*10^4=121,670,000.

How did you get 100 million?

• The state switched in 2000 — or thereabouts. Previously the letters went first, then the numbers. Then they switched and put the numbers first and then the letters.

• Jerry

Okay, but even if we say the letters have to come first, we get 121,670,000 combinations, not 100 million. Maybe the guy in the article meant that adding another digit produces 100 million *new* combinations.

Full disclosure: I’m a mathematician.

• Threads like this are my favorite part of NewsCut

• Jack Ungerleider

Full disclosure: I’m a long time recreational mathematician. 8^)

• Jack Ungerleider

There is bad math in this that doesn’t involve leaving 3 letters out of the 7 character license plate. (I’m assuming I, O and Q were used in the 6 character plates.)

Using the “Combinations and Permutations Calculator” at Stat Trek (For those who want to play along its at http://stattrek.com/online-calculator/combinations-permutations.aspx) we find that 26 letters in 3 letter combinations provides 15,600 permutations. Since there are 1000 numeric variations for each of those there would be about 16 million combinations not 20 million (that’s the bad math). Reducing the number of letters to 23 provides 10,626 permutations and the 4 digit gives you 10,000 variations for each permutation which would be 106,260,000.

• Jerry

When they compute “permutations”, they don’t allow for repetitions. For instance, they don’t count strings like AAA. Likewise for numbers, they’re not counting things like 111. However, somebody could have license plate number AAA111.

• Jack Ungerleider

Okay here is a revision to the original math that takes into account your concern. What we need to use is the Event Counter which provides the number of combinations for x independent events with n1 n2 n3 … possible outcomes per event.

3 independent events, each event has 26 possible outcomes.
Total possible combinations: 17,576.
Multiply by 1000 for the 3 digit number: 17,576,000 possible combinations

3 independent events, each with 23 possible outcomes.
Total possible combinations: 12,167
Multiply by 10,000 for the 4 digit number: 121,670,000 possible combinations.

For consistency I tried the calculation with 6 and 7 events adding 3 or 4 10 state events to the list and the results are the same as the above calculations. So it looks like they are gaining more than 100 million new combinations that will be less ambiguous. Probably a good thing all around.

• Jerry

I agree. In general, the “Event Counter” should just multiply n1*n2*n3…

• Postal Customer

I’ll remember it because I’m a license plate geek.

When I was a kid, Wisc was ABC-123 in 1986 and MN was 123-ABC. Then they
switched at some point, then I think they switched back. Of course,
before that, Wisc had different combinations like A1B 234, etc.

There are a number of really cool license plate sites out there. There was
an interesting NYTimes story about the California black plate coming
back and being immensely popular.

• tboom

When I was a kid Minnesota plates started with the number corresponding to the congressional district of your residence. As a kid I though it was really cool you could tell the region of the state someone came from just by looking at their plates.

By the time I got my first car Minnesota license plates were the most hideous orange on white with something like two letters followed by four digits. I say something like because I’m too lazy to go to the garage and dig them out … yep, kept the ugliest plates ever made just because they were on my first car. I had to keep the plates, the neighbors wouldn’t let me keep that rusted out hulk in the back yard.

• Joe

In Iowa, they still have the county where the license plate was issued on each plate. So you can tell exactly where people are from. Kinda fun.

• Jeff C.

In Massachusetts, the white plates with green letters that they stopped making in 1988 are kept on cars like a badge of honor. Classics. http://archive.boston.com/news/local/massachusetts/articles/2011/01/23/owners_wont_part_gently_with_vintage_mass_plates/

• I think I’ve got one of the white on brown they used before that one, too.

• KTFoley

I still remember the first Connecticut license plate that was issued to our family car — two letters, a dash, and four numbers — because a driver can keep that combo forever. My mom has had it on every car she’s owned since 1968.