Stopping sight distance is the minimum distance available

Stopping sight distance is the minimum distance available on a highway which is the

1. distance of sufficient length to stop the vehicle without collision.
2. distance visible to a driver during night driving
3. height of the object above the road surface.
4. distance equal to the height of the driver’s eye above the road surface.

SSD is the minimum distance available so that upon braking, the vehicle stops without collision.