Ambulance is always on an emergency
duty and is in a hurry to reach its destination. It needs
its path to be clear of any traffic jams and need to convey
its presence to the driver of the vehicle ahead. The letters
of the word AMBULANCE are printed backwards and are reversed
in sequence so that they appear legible when seen in a rearview
mirror. The driver of the vehicle ahead of ambulance can
see the word AMBULANCE in correct order.
The image of individual letters in the mirror show no right-left
reversal. However, the nonsymmetrical letters show a front-back
reversal, which appear as a top-bottom reversal.
The image of the vehicles behind appear laterally inverted.
For the letters of the word ambulance to appear in correct
order in the rear-view mirror, they are sequentially reversed
and are written in the left-right reversed order.
If you are still unclear about the concepts, please refer
the animation below.