One of the first things you will be asked to do by the examiner during the test is to demonstrate that you can read a car number plate from a distance of 20.5 metres (with glasses or contact lenses if you need to wear them). This fault is easy to avoid by regularly checking your eyesight, and getting fitted with the appropriate corrective eyewear as required. If you can't read the number plate the test will end there and then - i.e. a fail.