Ever since i got my first van i have always got the sign writing on as soon as possible.
I have lost count how often people have called after getting the number from our vans. So much beter than Yellow Pages or local papers.
But last week tried something different, i got the roof of one of our vans a transit sign written with our name and number and already have gained a 6 house builders clean, the site gaffer was surprised when he looked down and saw the number on the van, he dialled it from his mobile there and then.
You pay for the roof of the van so might as well use it.
Give it a try
cheers
Gordon