People die in car accidents because they may be drunk, tired or not paying attention to the road. Another View: The leading MEDICAL cause of death in vehicle accidents is due to injuries from blunt force trauma.
Possibly, but which wires? It is unlikely, though. Crossed wires would be much more likely to prevent your car from starting or from running after it begins to fire rather than cause it to die after it is started up and has gone into "run" mode.
That depends on the make, model, and year of car. If it is a ford from 1980 - 1990 then it is most likely a bad earth connection to the body of the car. Other cars have other problems that can also cause this.