A car can stop running while driving if it is out of fuel or because of some worn components like the alternators, fuel pumps, ignition switches or sensors. You may attempt restarting the engine or gently directing it to the side of the road if restarting doesn’t work.
Car engines can stall during driving for a number of reasons. In new and modern cars, faulty sensors can send the onboard computer the wrong information, thus causing it to set incorrect standards which in turn could cause an engine stall. In some cars, this will lead to the car’s “check engine” light coming on.
Additionally and most importantly, anything that toys with the engine’s supply of air or fuel can lead to a stall. This could be an obstruction in the system, a bad fuel pump or a clogged filter.
http://www.automobileglobe.com/why-does-your-car-engine-stall/