I think you are asking about the role of magnetism in reducing accidents.
So here is the answer:
1. Application of Eddy Current in the Vehicles:
 a) It shows us the speed of the vehicle through the speedometer. an application of eddy current which helps in determining speed and hence allows us to drive the vehicle within prescribed limits and avoid overspeeding
b)Brakes in some vehicle are based on principle of Eddy currents which help in stopping vehicle(mainly used in electric locomotives) during emergency as well as nomal condition
2. Magnetic Sensors: In every vehicle , there is production of magnetic field through certain conditions like alternator, movement of metals etc . This induced magnetic field is very helpul for magnetic sensors. This prevents the crash of vehicle by maintaining a required distance between two vehicles. Also during emergency , it controls the driving steering itself and controls the vehicle. But due to the cost inffectiveness of such instruments , they are less common.