The most important thing a good sign must possess is the ability to be loud. A sign must have a minimal amount of frills (these distract from the true meaning of the sign), and say something without the possibility of it being misinterpreted. If someone infers the wrong thing from a sign, it wasn't loud enough. A good example of a loud sign is a stop sign. This is a big red octagonal sign that says STOP on it. Unless you're blind, you will know exactly what it is trying to say. Even if you can't read English, you probably will stop because the sign is red. It jumps out at you and says, " HEY I'm red, that means STOP." If a sign is not loud, then it tends to get ignored.