Buckle up!

Seatbelts save lives! Many countries have over the last many decades grappled with the need to effectively communicate this message to its population. Compliance has varied between countries and over time. But their effectiveness at saving the lives of the car’s occupants and at preventing injuries remains the same across markets.

Research conducted across countries point to the same statistic – that wearing seatbelts cuts the risk of a fatality by half in the event of an accident at slow speeds. At high speeds the chance of surviving an accident is about 45 per cent and that of avoiding serious injury is more than 55 per cent (on average).

Yet, driving safety and seatbelt usage are rarely discussed until a tragic road accident involving a celebrity (or in our case a Minister) captures the national psyche. But awareness quickly drops back and compliance takes a back seat. Even in the most advanced automotive markets of the world, compliance is not cent per cent.

Seatbelts have been perfected to such a level that they have pretty much crested the development curve and incremental improvements can only provide marginal performance improvements. It is to the credit of the seatbelt that it is the single most significant safety device in a passenger vehicle. In fact, the effectiveness of most other life-saving safety features in a car is dependent on seatbelt usage (including airbags and roll-cages).

History The seatbelt has come a long way from its initial stages of adoption by the automobile industry. It has grown from being a rudimentary belt for preventing movement, to a significant safety restraint system, with its own clutch of assisting technologies. Like many other safety technologies for the automobile, seatbelts too were first introduced in racing, before making it to road-going cars.

The three point ELR (emergency locking retractors) seatbelt was first introduced in the 1960s and 70s in many countries in Europe and North America. This is the fundamental basis for all seatbelts of today.

The most important part of the seatbelt is the belt itself. Made of nylon, polyamide and other synthetic fabric, the belt is constructed in a tight weave. Called seatbelt webbing, the combination of its material and construction, gives the seatbelt its life-saving potential.

It is neither too hard and inflexible nor is it too elastic allowing an excess of stretch, both of which can potentially make it ineffective at protecting the passenger.

Seatbelt webbing is hardy, doesn’t chaff easily and is bacteria-resistant, making it the most ideal option.

If an accident occurs, the vehicle’s occupants are subjected to an opposing force if they wear a seatbelt. So, while the occupant’s body and his or her internal organs continue to travel in the direction of the car’s original movement, the seatbelt reduces the impact by stopping the occupant’s body along with the car. The three-point seatbelt also transmits the deceleration energy over the stronger parts of the occupant’s body such as the shoulder, chest and pelvis, so that the impact can be better absorbed.

In the event of a high speed crash, the seatbelts are the primary restraints that reduce the force of the impact, which then make airbags effective. Without seatbelts, airbags cannot prevent extreme bodily injury both external and internal – that is if the occupant hasn’t already been ejected from the vehicle. The modern three-point seatbelt has a number of assisting technologies that make it perform its job as a SRS better. Here are a few of them:

Load limiters Seatbelts are fairly taut and rigid by themselves. So there is a risk of them harming the occupant by becoming too tight from the restraining force during a collision. Load limiters do the job of reducing the amount of restraining force or load applied by the belt on the occupant. They allow a small amount of slack to achieve this targeted load threshold.

Pretensioners These are devices that complement the seatbelt’s attempt at preventing the car driver or occupant from falling forward in the event of a collision. In the three-point seatbelt, they also prevent the driver from sliding out of the seat and slumping (submarining) to the floor of the vehicle.

Though they may seem very contradictory, pretensioners have to be combined with load limiters to be effective at preventing injury. Pretensioners work in tandem with sensors that are similar to the ones used for airbags. When an impending collision is detected from rapid deceleration, a pre-emptive tightening of the belt by the pretensioner helps in prepping the occupant’s position to avoid impact injury and to make airbags more effective.

Pretensioners used pyrotechnic charges to explosively engage a piston to retract the seatbelt during the initial milliseconds after a collision. Many of today premium cars use an electrical version of the pretensioner that doesn’t need replacement and which also can be programmed to work in parallel with other safety systems. The PRE-SAFE technology of Mercedes-Benz is an example where the pretensioner works even when you engage in emergency braking or under extremely hard acceleration.

India has the dubious distinction of topping the list of countries with the most road fatalities. In our market, with the focus being so much on low costs, seatbelts offer the best hope for being a life saver. On average, driver speeds are also lower than in other countries raising the possibility of their effectiveness.

So, the next time you get behind the wheel or sit at the rear, remember to buckle up and if the annoying seatbelt reminder warning is not enough, it might help to keep a picture of a loved one next to the deity on the dashboard.