Definitions by U.S. Secret Service

hard car 

(n.) an armored or bulletproofed vehicle; used by the President and other VIPs for protection

Pete Garrison: Yeah, it's Garrison. Need a hard car for the President at Southwest Two.

Tom DiPaola: Coming to you, Pete. (to the driver) Go. Go! Go, go! Southwest stairs. Let's go get 'em.

-The Sentinel (2006)

hard car by U.S. Secret Service March 26, 2010