Ok I've officially finished the first iteration of a ghost mode script. I've outlined in the suggestions board but I'll put it here too.
At current the system will count down 15 seconds, and then each vehicle will check to see if any other vehicle is within 5 metres of itself, and if there is none it will turn ghostmode off for itself. However if there is it will keep ghost mode on and the car will blink its alpha to indicated that ghost mode is trying to turn off.
I've tested it as much as I can but really I'm certain there will plenty of little issues with it, so I'm hoping that over the next few days you can all just let me know if you have any difficulties with it, or any suggestions to improve it. That'd be great.
Cheers