Just one note that I haven't seen mentioned in this thread... one mistake that I have seen on signage (vehicular or otherwise) is color and typography choice (font). You want your signage to be READABLE:
First consider the contrast and values of the color of the vehicle as compared to the color of the lettering. Obviously the highest contrast would be white lettering on a black vehicle (or vice-versa). That doesn't mean you can't use color, but think of the VALUE of the colors (in otherwords, if you took a picture of it in BLACK & WHITE, how much contrast is there between the letters and the background.
On might think that red and green are going to contrast, but (depending upon the shade) they might actually be almost the same VALUE and be difficult to read from a distance. Look at signage from that perspective and you'll see what is most effective.
Regarding typography, avoid the temptation to get overly cute with the fonts you use. You should never use more than two
different fonts on a vehicle and if you want contrast in your typography, one should be a serif style and another sans-serif (serifs are the little legs on the letters).
A good article on the subject is here:
http://www.eyewire.com/magazine/columns ... /index.htm. (Other articles on typography by the same author:
http://www.eyewire.com/magazine/columns/robin/
You might think all of this is too esoteric, but it isn't. When you make choices for your vehicle signage, logo, invoices or business card you are making DESIGN decisions. In that sense we are all designers, some of us are just not very good ones. Like everything else, you CAN get educated on the subject. It isn't difficult at all, there are basically just 4 rules to remember: Contrast, Repetition, Alignment and Proximity. (I wish there was a good acronym for remembering those, but unfortunately.... wait!)
: )
Go to your local library (or interlibrary loan program) and request Robin William's most excellent (and THIN) book "
Non-Designer's Design Book" (used for as little as $2 at Amazon.com). It will give you an educated eye in a hurry.
Right now, you know simply that you "like" something or you don't (from a design perspective. After learning these principles, you will also know WHY.
Jeeez, that was a HELL of a First Post, wasn't it? (Sorry for the length)
i.c. stars