Protect the passengers and…the planet

Passive safety, active safety…

We now know that plastics make a significant contribution to weight reduction in modern vehicles. But one question always arises – does this come at the expense of safety? Is a light vehicle as sound and safe as a heavier car in the event of a collision? Rest assured, plastics play a significant role in the field of passive as well as active safety. Passive safety, or to be more precise palliative or secondary safety, concerns all of the elements that, by their presence or performance, can minimise the severity of an accident. Active safety, otherwise known as preventive or primary safety, is the amalgamation of all elements related to the vehicle that can, by their presence or performance, prevent an accident from happening in the first place.

Like being in a cocoon

And now let us turn our attention to one of the first things to be made compulsory in the 1970s: the seat belt. This was interwoven with polyester fibre threads particularly suitable due to their resistance to traction and therefore more likely to keep their shape. It is estimated that wearing a seat belt reduces the risk of death for a front seat passenger by about 50%. As for the airbag, star of the 90s, it is made from nylon and raises the number of lives saved by another 30%.

Plastics risk themselves to save lives

Do you remember those cars you used to come across thirty years ago? A rigid steel chassis, chrome bumpers and sometimes rubber ‘bananas’ to absorb the impact of a collision. The result of all that was that in the event of a collision, the deceleration was all too often fatal to the passengers. In this field plastic materials have enabled a significant number of lives to be saved. Let’s take the face bar: this polypropylene envelope is designed so that, at slow speeds, it dissipates the energy that it receives by distorting it reversibly. On the other hand, in the event of an impact at higher speeds, the distortion is no longer elastic but plastic, in other words irreversible. When it makes contact with the face bar, the chassis structure is designed to lose its shape and crumple like an accordion, absorbing the maximum amount of kinetic energy and thus protecting the car’s interior and its occupants.

Nor has the pedestrian been forgotten, as the shape of the face bar is designed to dissipate the energy of the impact as effectively as possible and so that the point of impact is located at the level of the pedestrian’s lower legs, a part of the body that has no vital organs. In addition, the polypropylene that forms part of the composition of this part of the bodywork eliminates sharp edges when it breaks up, thus avoiding more serious injuries.

Tradesmen are also grateful

Safety also concerns tradesmen and especially their commercial vehicles. The days when they were fitted out with plywood boards are numbered. In the event of a collision the wood breaks and hundreds of splinters are sent flying into the front of the vehicle like arrows. The European Union is keeping a close eye on this problem and in the next few months could make it compulsory to fit these vehicles with plastic materials. Another advantage of plastics is the lighter weight of the polymers and thus lower fuel consumption and reduced CO2 emissions.

The aftermath

The target set by the European Union is substantial. As from 1 January 2015, the rate of recovery and recycling of end-of-life vehicles will rise to a minimum of 95% per vehicle per year. The recovery and recycling rate for these vehicles will be fixed at a minimum of 85% per vehicle per year, thus leaving 10% for energy recovery. These figures have been increased significantly, because today, the rates stand at85 % and 80% respectively. Will the target be achieved? With difficulty, according to the manufacturers, but it is not unrealistic. That said, recycling has been a major concern for the automobile industry for the last twenty years, and the vast majority of manufacturers have not waited for European directives. Indeed, more than 5% of the plastics used in a vehicle currently come from recycled materials, and this figure will continue to grow over the coming years. Ten years ago, recycled plastics amounted to 0.5% of the total mass of a vehicle, while today that figure is very nearly 10%.