The range of headlights of car is the maximum distance (s) upto which an obstacle on the road can be seen by the driver . The car must stop before it hits the obstacle . If a is retardation produced in the car by applying brakes , then to stop the car within the distance s , the speed upsilon of t the car must be less than `sqrt(2 as)` Hence the speed of driving a car safely depends upon s , the range of head lights .
