Sign Size versus Importance
Billboard
Size: 1,200 square feet, 50 ft tall
Importance: negligible
Hospital Sign
Size: 4 square feet, 6 feet tall
Importance: Life vs. death.
"If people didn't use billboards, we wouldn't be in business...we provide a service for people that can't adverise in ANY other way"- a representative of Trinity Advertising (Decatur) on APT's For the Record November 9, 1999.
If the size of a sign were a function of its importance, this situation would be reversed.  Obviously, signs do not have to be of gargantuan size in order to be seen!