AIRBAGS - THE COST OF INFLATION

ONCE A LUXURY LIFE SAVER, AIRBAGS ARE NOW FITTED TO EVEN THE CHEAPEST CARS. YET DO YOU REALLY NEED THEM, ARE THEY DANGEROUS AND HOW DO THEY WORK? JONATHAN CROUCH REPORTS

Not long ago, top German motor racing driver Bernd Schneider was hurling his Mercedes touring car around the twists and turns of Europe’s most dangerous motor racing track, the 14 mile-long Nurburgring circuit built among the Eiffel mountains south of Frankfurt.


Barrelling down through one of the many chicanes, his car crashed against the kerbing, inflating to his surprise the airbag that Mercedes insist is fitted even to their racing machines. Just what he didn’t need at over 100mph in the middle of a forest...


It’s the kind of incident that sums up the fears of millions of people who see the current trend towards airbags for even the cheapest cars as the kind of fashionable accessory they could do without.
Yet examine the facts and there’s a strong case not only for having airbags but for making them compulsory. There’s also, as Herr Schneider found, little reason to fear...
Airbags are the flavour of the month just at present. No major manufacturer can afford to offer a family car without one and many are fitting them to even their cheapest offerings.
Curiously, this is one of the few areas where Japanese manufacturers have lagged behind, with most of the major names belatedly following the lead taken by their European competitors.
The airbag concept - a large cushion which explodes from the centre of the steering wheel to protect your head when the car sustains a violent front impact - was originally a European concept anyway. Mercedes-Benz pioneered its development way back in 1967 and little in essence has changed since.
All Airbags Are Not The Same
The fact that your car is fitted with an airbag should not give you a false sense of security. Unlike the 60-litre airbags used in the USA (where seatbelt wearing is not compulsory in some states) the smaller 40-litre `Eurobags` that most cars use here must work in conjunction with seatbelts if they are to be really effective.
Only a handful of car manufacturers, Mercedes and Saab for example, specify the more expensive American-sized airbag as standard for complete protection. Ask which type your car has before you buy.
Front passenger-side airbags are becoming more common too. Ford, for example, will sell you one for a few hundred pounds in a Fiesta - and though their lead is an exception now, you can bet that it won’t be for long. These are larger than those for the driver; 56-90 litres in Europe and 120-200 litres in American specification. Again, make sure you know what you’re buying.
Future developments are likely to include the fitment of side-impact airbags which are mounted in the doors and inflate when the car is struck from the side. The problem until now with these has been the tiny space available for cushioning and the rapid impact-sensing and inflation needed for them to be effective.
Airbags built into the back of the front seats to protect rear seat passengers are also possible - though these are less likely. Research has shown that the front seats move forward in impact in any case; provided back seat passengers are properly belted up, there’s little chance of any facial impact.
How Do They Work?
Extremely quickly is the short answer. Typically, an airbag will be fully inflated within 30 milliseconds (0.03 secs) after the point of impact. To ensure that it doesn’t go off accidentally, or trigger in minor impacts, a threshold deceleration has to be reached before the sensors activate inflation. In Europe, this can be anything from 12-20mph.
There are few recorded instances of airbags going off accidentally. They’re manufactured to military equipment standards, hermetically sealed and designed to last at least ten years. Providing that the triggering mechanism is working properly, malfunctions are almost unheard of.
Manufacturers do warn however, against exposing them to excessive heat (such as would be generated by a blowtorch or welding equipment), ill-advised tampering by DIY enthusiasts (don’t) and excessive bashing of the module in the centre of the steering wheel.
Parents must also ensure that rear-facing child safety seats are not placed in the front, should the car be fitted with a passenger side airbag. Simulations with full-sized American airbags have shown that children can be harmed in this way.
Though the danger is not as great with the smaller `Eurobags`, don’t take the risk. Use an approved rear safety seat, bearing in mind that very young babies should have a rear-facing, not forward-facing, seat.
Are They Effective?
If used in conjunction with a seatbelt, the answer is emphatically `yes`. The best known evidence is a story of an accident in the American state of Virginia. The two cars involved were both 1989 Chryslers and hit each other head-on at a closing speed of 68mph.
Instead of being killed outright, both drivers survived the crash with only superficial injuries, despite the fact that one of them was not wearing a seatbelt. Recent tests have shown that even at slower collision speeds of 19-31mph, 30% of belted drivers received head or chest injuries in cars not fitted with airbags, a figure which rises to 70% at higher speeds.
Though only 3% of such injuries are likely to be fatal, the remainder often cause disfigurement or debilitation. A permanent reminder in other words.
What Happens When It Goes Off?
There’s an explosion no louder than the sound of a paper bag being burst which propels the nylon bag towards your face. Since it’s not completely gas tight, it will automatically deflate again within a split second so as not to impair your vision or hamper your escape from the car.
It doesn’t hurt - volunteers describe it like being hit with a pillow - and since an airbag distributes the force of impact so evenly, it’s unlikely to shatter your glasses. Even if you’re smoking a pipe, there’s little danger, it’s likely that the force of deceleration will have flung it from your mouth.