I imagine most of you will remember the flags that used to be flown on (Especially) white vans - These were 'I'm a Crap Driver' signs , but fell out of favour when it was pointed out that they increased
wind resistance and interfered with fuel economy . The solution was a sign inside the car , and these came in two styles ! The 'Baby on Board' and the 'Prebooked Private Hire' stickers .