Various new Ford cars are available with the rear inflatable seat belt system, which has been specifically designed for the back seat, where passengers more prone to injury, such as children, are more likely to sit. While the belt initially looks like a conventional 3-point harness, it is actually slightly larger and softer. This is due to the balloon-like airbag housed inside the length of the upper portion of the belt.
When the vehicle's crash sensors detect an impact (typically of at least 8mph) a highly compressed mixture of argon and helium gas is released from a small tank stored under the seat. A conventional airbag uses a pyrotechnic inflator, the gases of which would be too hot to hold so close to the chest, so an alternative inflation system had to be used.
The gas is pumped through a special, pipe-like buckle into the belt, causing the airbag to burst through the seams of the belt and fully inflate in less than 40 milliseconds. This system is designed to spread the crash forces across five times the body area of that of traditional seat belts, thereby reducing the amount of pressure exerted on the individual's chest.
Seat belts help to save over 2,000 lives a year in the UK, but here at Ford we found a way to improve them even more.