For airport security signs, see Security Information.
Mandatory Instruction Signs
These are white characters on a red background. Pilots must not proceed beyond a mandatory sign without an ATC clearance to do so.
An information sign should be provided where there is an operational need to identify by a sign, a specific location, or routing (direction or destination) information. These include: direction signs, location signs, destination signs, runway exit signs, runway vacated signs and intersection take-off signs.
An information sign, other than a location sign, should consist of black characters on a yellow background.
A location sign is yellow characters on a black background. The location sign is used to identify the location the pilot is at, usually a taxiway.