ABSTRACT
What do we know about kinetic energy, the (almost) universal direct cause of injury in a crash on the road? We have known for more than three centuries-since Isaac Newton described the laws of motion in the seventeenth century-that the amount of kinetic energy generated by a moving object is a function of half the mass (the weight) of the object multiplied by the square (multiplying the number by itself) of its velocity (speed), so speed is far and away the key determinant of the amount of the force unleashed in a crash.
