The document discusses stopping distance and braking efficiency. Stopping distance can be divided into three parts: reaction time, time for brakes to engage, and net stopping distance depending on deceleration. Braking efficiency is measured by the minimum distance needed to stop a vehicle from its speed after brakes are applied. Stopping distance depends on tire tread, inflation, and road surface conditions as well as the vehicle's velocity. Stopping distance can be calculated using the equation D=kV^2, where k depends on the braking system. Braking efficiency can be calculated as η=V^2/3D and is rated from perfect to very bad depending on the percentage.

1. Stopping Distance
And
Braking Efficiency

2. Stopping Distance
The total stopping distance in case of emergency braking may
be divided into 3 parts.
1. Distance transverse during the reaction time of the driver.
2. Distance transverse during the time elapsed between the
driver pressing the pedal and brake being actually applied
at the wheels.
3. Net stopping distance, depending upon the deceleration.

3. • For practical ,measure for braking efficiency
that of the minimum distance in which it can
be brought in to rest after the brake is applied.
The stopping distance depends upon
1.Grip between the tyre and road surface.
2.Tyre tread condition.
3.Tyre inflation.
4.Nature of road surface.

4. • The stopping distance is calculated by
D= k * V2
Where ,
 D=stopping distance in kilometres.
 K=Constant depending upon the road and
tyre inflation.
 V=velocity of the vehicle per hour.
Note:-
The value of k is 1/25 for 4 wheel braking system.
1/12 for 2 wheel braking system.

5. • The braking efficiency is calculated by the
equation
η=V2/3D
Where,
V=velocity of the vehicle
D=stopping distance.
Condition of Brake Braking efficiency in %
1.Perfect 90%
2.Excellent 77%
3.Good 70%
4.Fair 60%
5.Poor 50%
6.Bad 37%
7.Very bad 30%
Below Fair is very danger.