This came from a listener named Daniel Goddard:

Back in the late seventies when I was in college, I had a vanity plate that read: "BO IN" What was the car?

Answer: Bo in Arrow. Plymouth Arrow.

In 1973 our listener Steve Blunden had a license plate that read "16OZO." (Here's a hint, he was never rear-ended.)

Answer: Pinto (16 oz = 1 pint, + o = Pinto)

Shlomit Aucielloe wrote:

"...one of my mother's doctors has a license plate that read's 'OLOGIST.' Can you guess the car and the guy's trade?

Answer: Audi-ologist

Susan Krouse saw this license plate on a Chevy in North Carolina: "VLAD THE"

Answer: Impala

[ As Read on Car Talk]