Consider the following distances:
d1 = distance travelled by the vehicle after applying the breaks.
d2 = distance travelled by overtaking vehicle, during reaction time for overtaking.
d3 = distance travelled by overtaking vehicle, during total overtaking time.
d4 = distance travelled by overtaken vehicle, during total overtaking time.
The Overtaking Sight Distance, on a road with one-way traffic will be equal to:
1
d1 + d2 + d3 + d4
2
d1 + d2 + d3
3
d3 + d4
4
d2 + d3