9. Car crash testing

Some things are too dangerous to test out in real life, and one of them is a car crash.

But it is vital that the design of a new car is made as safe as possible. Occupants (and pedestrians) must be kept as safe as humanly possible in that situation.

Engineers know how metal bends and twists under massive force - they have equations that describe it.

This is why 'crash models' are possible. A computer simulation, driven by mathematics, crashes a car in 'virtual' space. Engineers see how the car will crush, from the side, from the front and from the back - then they add a strut here or a bulkhead there, to try and divert the massive forces in a car crash away from its passengers.

From all this modelling work a working design comes out.

Finally, a real car is built called a 'crash mule'. It contains hundreds of sensors and fully instrumented crash dummies. A crash mule can easily cost a million pounds to build - then they deliberately crash it. Every microsecond of the crash is recorded by the sensors and stored as computer files. All this data is then fed back into the model to make it even more accurate.

After years of work the proven final design is in place and the car is ready for assembly.