..or the last car has a man on board driving along.....camera turns to back window where there is no sign whatsover...then camera moves down and focusses on a window sticker instead which reads something like "No Sign on Board"..giving some kind of end to the 'sketch'? Maybe I'm thinking too much now..dangerous when i do that... 
or maybe an on board sign with an sign on board on board sign ?? getting stupid now im officially killing my thread !!! hollyoaks has just started anyway
One car's crashed at the side of the road. 'Blind man on board'.
yeah or 'corpse on board' ha ha i like that, nice work
infact that would make a good drink drive ad, have a bloke in a car n have the sign saying drink driver on board then have a voice over saying its this easy for polite to spot a drink driver
I can't believe I've got the nerve to even do this but maybe a team of mountaineers in a campervan with all there equipment strapped to the roofrack and their sign saying....
"Climb on board" 
right thats it, close this thread
Last word!