Not that you should try driving your car backwards, but this is an interesting fact.
Theoretically, you should be able to go as fast in reverse and you can drive forwards. The engine runs the same speed whichever way you are going.
However, the one crucial difference is that the car has gears and these enable the car to go faster or slower.
So it has four or five gears when driving forwards but only one when you reverse – which is the equivalent of first gear.
Unfortunately, when reversing your car the mileage does not go backwards – which is a real shame.