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 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!
"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.