As the bag expands, it blows the plastic cover off the steering wheel and inflates in front of the driver.As the explosive burns, it generates a massive amount of harmless gas (typically either nitrogen or argon) that floods into a nylon bag packed behind the steering wheel.Older airbags used sodium azide as their explosive newer ones use different chemicals. The heating element ignites a chemical explosive.The airbag circuit passes an electric current through a heating element (a bit like one of the wires in a toaster).Normal braking doesn't generate enough force to do this. If the deceleration is great enough, the accelerometer triggers the airbag circuit.An accelerometer (electronic chip that measures acceleration or force) detects the change of speed.When a car hits something, it starts to decelerate (lose speed) very rapidly.Modern airbags (installed since the late 1990s) fire with less force than older designs,Īnd there's compelling evidence that this has reduced accidental deaths, especially among children, without compromising passenger safety. Even so, it's clearly important to study the potential dangers of airbags so we can make them as safe and effective as possible. If an airbag saves your life, you probably consider a slight risk of injury a price well worth paying. The biggest risk is to young children, though adults also face a small risk of That's obviously a huge improvement, but it's important to note that airbags are violently explosive things that present dangers of their own.
CAR ACCIDENT SIMULATION GOING THROUGH THE WINDSHIELD MANUAL
They found that airbags reduced fatalities by 23–24 percent in head-on crashes and by 16 percent in crashes of all kinds, compared to cars fitted only with manual safety belts. Major study of road traffic accidents over eight years from 1985 to 1993. In 1995, Adrian Lund and Susan Ferguson published a There any proof that they reduce fatalities? How effective are airbags?Īirbags sound like they must be a good idea, but scientists like hard evidence: is That's important: if the bag didn't deflate, your head would just bounce back off it and you'd be no better off. The basic idea is that the airbag inflates as soon as the car starts to slow down in an accident andĭeflates as your head presses against it. Replace them (relying on an airbag to protect you without fastening The word "supplementary" here means that theĪirbag is designed to help the seatbelts protect you rather than This dummy, whose name is "Adam," doesn't test crash responses: he's designed to sweat like a real person so researchers can test the climate conditions inside a car! Photo by Warren Gretz courtesy of US Department of Energy/National Renewable Energy Laboratory (DOE/ NREL).Īs a supplementary restraint system (SRS) or supplementary Photo: A typical crash-test dummy has over 130 different sensors packed inside. Steering wheel or the glass windshield (windscreen). Physics says your head will keep on going and smash into the Your head weighs a surprising 3–6kg (6–12lb)-as much as several bags of The biggest problem is that they restrain only your body. Have had seatbelts for decades, but they're a fairly crude form of On moving until something (a force of some kind) stops them. Newton who first stated it) that things that are moving tend to keep Newton's first law of motion, after brilliant English physicist Sir Isaac Moving car have mass and velocity too and, even if the car stops, Violent the collision, and the greater the chance you'll be injured or killed. If a collision brings your car to a halt in a certain time, the more energy you have, the more The more kinetic energy you have, the more you need With the square of your speed (your speed × your speed). That's because your kinetic energy increases Even though cars are designed to crumple up andĪbsorb impacts, their energy still poses a major risk to theĬhart: The faster you go, the harder it is to stop. To stop-or until you crash into something. The faster you're going, the more kinetic energy it has. Kinetic energy, and the heavier your car and (loosely, this is the same thing as speed, but strictly it means "stuff" an object contains and it's closely related to how heavy it Moves has mass (very loosely speaking, this means how much Car crashes are controlled by the laws of physics-and, more specifically, the
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