To effect a passing manoeuvre, a driver must leave the racing line to go around the car in front. When this is done on a corner, the challenging driver has two options, to cut inside the defending car or to take a long way around the outside of the racing line.

This longer path is known as the outside line and is often fraught with danger as the track is green and can be covered in marbles or they may run out of track. 

Andrew Burden

The author Kiwi F1 Fan