slang The speed limit of 55 miles per hour. The US nickel, which is worth five cents, at one time featured a picture of a buffalo. Whoa, whoa, cool it with the double buffalo—the speed limit here is 25!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
See double nickels
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.