I've researched this to death. A sign like this has about 3 seconds to do 3 things.
* Get there attention
* Relay the message
* Get them to remember it
When people are driving by my trailer they may have 5 seconds to do this. If the trailer and the customer are both driving, 3 seconds is the max. I thought about what the ABSOLUTE most important thing was that I wanted that person to remember when they saw my trailer.
Hands down... I want them to remember the phone number.
Everybody in this town pretty much knows who I am, but they don't all know how to reach me.