I believe that the motion of the moving object i.e the car is irrelevant as the light particles leaving the torch will always be traveling at light speed and as light speed is the universal speed limit and that if an object travels faster than light speed time would slow to correct that universal error thus always maintaining light speed so the speed of the car would just become null and void, the time displacement that occurs to correct this sort of error would be minuscule and not even noticeable unless traveling at such speeds for a long period and would only effect the object moving at light speed, that is what I believe until proven that light speed is not the limit.
Also I enjoyed swansont's analogy of the ball throw, if you threw a ball at half the speed of light out of an object also moving at half the speed of light you would just simply keep up with the ball, most likely resulting in the ball hitting you in the face as it loses velocity and you maintain half light speed.