2187, unfortunately isnt  for someone by the name of Elwood Blues. By dissecting the license  number, you can find out information about the holder. Birthdate:  July 1st 1952 (Dan Aykroyds birthday) Gender: Male First Initial:  D, Middle Initial: E. Last Name: Starts with a B, followed by a  guttural or sibilant (C, G, J, K, Q, S, X, or Z), followed by a  short liquid (R), followed by a dental (D or T). The drivers  license number turns out to be what Dan Aykroyds license number  would be, if he had obtained an Illinois license, simply  substituting the leading A with the B for "Blues"; thus the  number shown in the film is a "hybrid" and is an invalid Illinois  number. The book "Blues Brothers: Private" by Judith Jacklin gives  Elwoods birthday as December 6, 1953. Therefore, Elwoods drivers  license number should have been: B420