Even if GZ was aware of the sign
That the sign is actually there is just a vivid illustration of a point that I have made before.
Zimmerman's claim to have gotten out of his truck to 'look for a street sign' is absurd on its face. A person looking for a street sign doesn't get out of his vehicle at a bend in the street. He drives to the next intersection.
why would he walk all the way back to his truck
Because he wanted to meet the police at his truck. That's one point Zimmerman was quite consistent about.
Why would Zimmerman want to stand in the rain while waiting for the police?
turn it around
Zimmerman's truck was already pointed in the right direction. He would just have to drive around the bend. After reading the sign he would have had an intersection to turn around in.
drive to a sign
That sign would have given him the name of Twin Trees Lane, the street whose name he said he wanted and on which his truck was located.
get out to see a house number
I don't see why he couldn't read a house number from inside his truck.
Much easier to walk the few extra feet to Retreat View Circle and note a house address.
Zimmerman said that he was looking for a street sign from the moment he got out of his truck.
In the reenactment Zimmerman was about 100 feet west of RVC when he said he looked down the dog walk and didn't see Martin.
Zimmerman said he started returning to his truck after reaching RVC, so he wasn't saving any walking distance with what would have been a 200 foot round trip.
What would be the point of Zimmerman giving the police an address on RVC, if he was going back to his truck to meet them there?