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What is SRS?

What is SRS?

As the car is one of the most dangerous vehicles, it is equipped with a huge number of security systems that can save lives for drivers and passengers at the time of the accident. Today, almost all new cars are equipped with the so-called SRS system.

SRS is the abbreviation of the English phrase Supplementary Restraint System. Literal translation is the value – an additional restraint system. Sometimes SRS is called a passive safety system.

The passive safety system is a whole complex of elements that work during an accident. There are several options for picking SRS depending on the brand of car but the most common is the following:

  • Airbag for the driver.
  • Passenger airbag in the front seat (next to the driver).
  • Panel to enable or disable the passive safety system.
  • Frontal airbags.
  • Rear airbags.
  • Diagnostic health system SRS.
  • A lightbulb indicating a problem in the system.
  • Passive safety control panel.
  • Sensors for collision detection in front.
  • Sensors for collision detection from the rear.
  • Sensors for collision detection from the side.

Despite the fact that the SRS is an entire system in most cases it can only mean an airbag.

AirBag is a pillow made of elastic material, hollow inside. At the time of the accident, the system is triggered, the airbag is filled with the gas, which makes the impact on the collision softer.

The driver’s and front passenger airbags are located in different places. Airbag for the driver is located in the center of the steering wheel, in a specially designed box. The airbag for the front seat passenger is located on the top of the glove box on the front panel.

Date of first implementation and history of SRS origin

Initially, airbags SRS were used exclusively in the aviation sector but due to the reliability of this method of protection, they migrated to the automotive industry. In airplanes the airbags were used already in the 40s of the 20th century but were patented only after ten years.

For the first time, airbags began to equip cars only in 1971 when the American Allen Breed presented his creation to the automobile company Chrysler. At that time AirBag SRS included the pillow itself, as well as a sensor that was able to determine the moment of an accident. The invention of Allen Breed could significantly reduce the death rate of Americans as a result of a traffic accident. After all US residents rarely used the invented early seat belts.

First Ford cars were equipped with airbags in 1971. Further in 1972 AirBags appeared in vehicles manufactured by OldsMobile. Two years later, cars began to be equipped with an additional airbag – for the passenger in the front seat.

Despite the effectiveness of airbags, the Americans treated them skeptically. However, in early 1970, the Ministry of Transport of America offered to equip all cars with airbags.

The German automobile company Mercedes-Benz in 1983 developed its unique version of the airbag and began to equip it with a limited number of cars. The variant presented by the company differed from the prototype in that it was activated only in the event that the seat belts were powerless. The airbag was triggered by a special sensor.

After that, more and more manufacturers began to equip their cars with airbags, and already in 1984 in the United States of America came a bill that obligated mandatory airbags.

The front airbag was invented only in the mid-90’s, and on motorcycles SRS appeared only in 2006.

Initially, cars were equipped with airbags which protected only the driver of the vehicle – Driver AirBag (DAB).

The basic principles of SRS operation

In order for the SRS system start to work, certain conditions are necessary: the car must face an obstacle at a speed of more than 50 kilometers per hour. This is regulated by special sensors. In addition, the airbag does not work when colliding with soft objects (for example, bushes).

When an accident occurs, special indicators are triggered that give a signal to the pyro chucks. This leads to the disclosure of AirBag. The system is equipped with generators with dry gas inflating the cushion. The hollow space fills the gas instantly – at a speed of up to 300 kilometers per hour. Since this is a huge force, a non-buckled seat belt can lead to serious injuries to the passenger and the driver.

At the time of activation, the airbag touches the head of the driver or passenger while taking full force of impact on himself and providing reliable protection.

After the airbag deployment, the system transmits a signal to the pretensioners of the seat belts. Further, the sensors of the system analyze the state of the central lock of the car doors. If it is closed SRS automatically opens it.

You can find out the status of the SRS system using a special indicator on the car’s panel. If it is lit, the passenger or driver may not have fastened their seat belts or adjusted the seat backs incorrectly.

When all possible causes for which the system signals a malfunction are eliminated, the indicator is still lit, it is necessary to perform a technical inspection of the vehicle and to eliminate the cause of the malfunction.

In the passive safety system there is also an electronic unit, which constantly checks the condition of the airbags for serviceability when the vehicle is ignited,. If a problem is detected, the indicator light on the panel labeled “SRS” or “AirBag” lights up.

Pros and Cons of SRS

The passive safety system is quite reliable. It has, as well as huge advantages and some disadvantages.

Advantages of SRS airbags are as follows:

  • This is a reliable way to protect yourself from injury or death in the event of a traffic accident at high speeds.
  • Airbags are not visible, they do not create a feeling of discomfort while driving in the car.
  • Unlike the seat belt, the pillow does not need to be fastened or unfastened.
  • It works very accurately and instantly.
  • High degree of protection of vital parts of the human body: the chest and head.
  • The airbag takes up 90% of the collision impact force, and only 10% is the driver or passenger of the front seat.

The study was conducted in 2009, during which it became clear that due to the passive safety system managed to save more than six thousand lives of drivers and passengers of vehicles.

Like any other system, SRS also has some disadvantages:

  • If the seat belt is incorrectly fastened, serious injury may result.
  • Airbag will not be able to protect passengers and the driver if, at the time of the traffic accident, the car turns over or bumps sideways.
  • Sometimes the airbag can work accidentally.
  • While the inside of the airbag is filled with air or gas, the pillow emits a lot of noise.
  • After a one-time operation of the SRS system, it is no longer operational and must be completely replaced, which can severely be expensive for the vehicle owner.

Despite some disadvantages of the SRS airbags, they must be in every car, as it is a guarantee of safety and reducing the likelihood of death of passengers and drivers at the time of the traffic accident.

How much the SRS system is popular among drivers and automakers

Enormous popularity among drivers and automakers SRS airbags have acquired in 80 years of the twentieth century. With each year of its existence the system of passive security has been constantly improved. Today, almost all modern cars are equipped with the SRS system and in some new models it is even more refined.

In addition, if you take a used car then there is a high probability that the system of passive safety is missing. This is due to the fact that after triggering at the time of an accident the SRS system can no longer perform its original function. However, due to the high cost of replacing the passive safety system, most car owners do not want to install it again. When buying a used car, it is necessary to make sure of the presence of airbags and the serviceability of the passive safety system.


Date: 12.11.18     Views: 216