This is the era of automobile revolution. People in old days looked for comfort luxury and economy, but now a day they are keener on safety. Safety places an important roll on the design and production of modern car. A lot of research and developments made in this field and hence a lot of safety devices are implemented on modern cars. In the two decades, automobile technology is evolved so much and, more and more safety systems have been incorporated into the car in an attempt to make them safer. Safety systems in automobiles are classified in to two o Passive safety system o Active safety system Active safety systems are those systems, which are active during driving and help in avoiding and preventing accidents. Passive safety systems get activated only at the time of an accidents and helps in ensuring safety to the occupants during the crash. Automobile technology continues to grow and evolve at an ever-quickening pace, and the changes that are coming will continue to challenge those, who have fix tomorrows automobiles. There are many safety features now available as standard equipment. Some of these include the electronics stability program (ESP), secure tyre system, Anti-lock braking system, airbags and seat belts. The number of automobile is growing rapidly and so do is the number of accidents. This paper tries to review the emerging safety systems that are incorporated in today?s automobiles to prevent accidents as well as ensure maximum safety to the occupants.

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FUNCTION
To maintain the stability & steer-ability of the vehicle while the wheels are impending lock or skid in varying road conditions during braking.
To maneuver in your intended direction during “panic-stop” situation.
To stop the vehicle with minimum stopping distance.
DESIGN & WORKING-EARLY ABS
Consisted of Mechanical components only-Drum, Flywheel.
Relative angular speed difference between Drum & Flywheel causes some drop in main hydraulic line & thereby reducing brake pressure in the adequate amount.
DESIGN & WORKING-TODAY’S ABS
COMPONENTS
Speed Sensors-The anti-lock braking system needs some way of knowing when a wheel is about to lock up. The speed sensors, which are located at each wheel, or in some cases in the differential, provide this information.
Pump-Since the valve is able to release pressure from the brakes, there has to be some way to put that pressure back. That is what the pump does; when a valve reduces the pressure in a line, the pump is there to get the pressure back up.
Valves-There is a valve in the brake line of each brake controlled by the ABS. On some systems, the valve has three positions:
In position one, the valve is open; pressure from the master cylinder is passed right through to the brake.
In position two, the valve blocks the line, isolating that brake from the master cylinder. This prevents the pressure from rising further should the driver push the brake pedal harder.
In position three, the valve releases some of the pressure from the brake.
Controller-The controller is a computer in the car. It watches the speed sensors and controls the valves.

PRODUCT ARCHITECTURE

FLOW CHART
AGENDA
ABS – Function, Design & Working.
ABS types.
Recent Advancements.
Effectiveness & Limitations.
Testing & Validation.
Job of the Driver.
Closing Remarks.

Anti-Lock Brake Types
Four-channel, four-sensor ABS-This is the best scheme. There is a speed sensor on all four wheels and a separate valve for all four wheels. With this setup, the controller monitors each wheel individually to make sure it is achieving maximum braking force.
Three-channel, three-sensor ABS-This scheme, commonly found on pickup trucks with four-wheel ABS, has a speed sensor and a valve for each of the front wheels, with one valve and one sensor for both rear wheels. The speed sensor for the rear wheels is located in the rear axle.
One-channel, one-sensor ABS-This system is commonly found on pickup trucks with rear-wheel ABS. It has one valve, which controls both rear wheels, and one speed sensor, located in the rear axle.