With time, a significant increase in the automobile population on roads has been observed and is likely to go higher and higher in the near future. Automobiles have become the most used mode of transport among people. Increase in the number of road accidents is also due to increased vehicle population, road conditions, driving errors and speed limit violations. Thus the vehicle safety is an important area of concern for all car manufacturers. The vehicles are designed and equipped with safety technologies for improving the crash worthiness of the vehicle.
Safety in automobiles can be classified into two : active safety and passive safety. Active safety includes those systems which are installed in the vehicle for prevention of crash. Electronic stability system, Anti-lock braking system, and traction control system are few examples of the active safety methods. Passive safety includes those systems that will protect the occupant from injuries during crash. Airbags, seat belts, rollover structures represent some of the passive safety methods.
In high end vehicles, a technology for crash information has also been placed. The crash detection sensor will trigger the GPS (Global positioning System) for locating the site of crash along with a notification all to the nearest hospital’s to the crash site.This significantly leads to less deaths during accidents.Various safety regulations are framed and it is the responsibility of the car manufacturers that their vehicles go through all safety tests.
Next lets look into the passive safety technologies in automobiles.
They help in restricting the motion of the occupant by stretching itself. It helps in protecting the occupant by not allowing him to eject out of the vehicle during a fatal crash.Thus it is advised to wear safety belts whenever you traveling in a car. It is mandatory for all the vehicles.
These are basically cushions which are activated during a collision. The air bag gets filled with a gas as soon as the collision occurs and does not allow the occupant to hit on the steering wheel and the doors. Thus it reduces injuries by absorbing the impact of the collision. Thus an air bag wants to reduce and slow down the passenger impact speed to zero. However with stringent safety norms coming in the near future, all the vehicles will be equipped with air bags. Air bags are mounted on the steering wheel to resit the impact of a frontal crash. Door mounted side air bags prevents occupants form injuries during any side impact on the vehicle. Air bags are made of very thin nylon fabric. The functioning of the air bag depends on the crash detection sensor. The sensor provides the signal for air bag inflation. Inflation happens due to the reaction of sodium azide and potassium nitrate which results in a hot blast of nitrogen gas.
The lamination of the windshield helps in keeping windshield into one piece during frontal crash or even in case of pedestrian collision. When the glass breaks, unlike ordinary glasses it results in formation of granules with no sharp edges. This helps in keeping the occupants and pedestrians safe from injuries due to the glass particles. Also these laminated glasses have to undergo testing according to the safety norms before they can approved for installation in vehicles.
Crumple Zones, Safety Cell:
These zones absorb the impact of collision. Vehicles can have front, rear and even side crumple zones for protecting the occupant from high impact forces. These are made of shock absorbing materials like polyurethane.This refers to the safe design of the passenger compartment. The design needs to be made in such a way that there is a scope of survival space after the vehicle has undergone a crash. This helps in the movement of the occupants and will also help them in getting themselves out of the vehicle. High strength steels are sued for making such designs which can withstand the huge impact forces.
Roll over bars:
Many road accidents happen due to the rolling of the vehicle. The roll over structures in the chassis are made for such scenarios and are able to resit the impact forces on a vehicle roll. Roll sensors are also available in some vehicles which provides the signal of rolling tendency which results in the slowing down of the vehicle speed to avoid any roll.
All the above methods are first virtually tested on computers. Crash simulations are performed on computers to study the impact forces, type of impact, air bag functionality and survival space. This results in the fast development of vehicles which are then simulated for real life conditions. The crash is conducted on vehicles and the results are co-related with the computer simulation results. This allows easy understanding of the vehicle behavior during a crash.