Why doesn't the speed of light increase in this situation?

Let's say you have a vehicle that is moving at 60 MPH. If you shine a beam of light in the same direction as the car is traveling, the beam of light will move at 299,792,458 meters per second (speed of light), not (299,792,458) + 60MPH. Why doesn't the speed increase by 60 MPH? Does inertia have no affect on the speed of light?

Is it possible that we can use this information in future technology?