Be wary of these answers you've been receiving. All of these people are mistaken, with the exception of Technobuff, and I highly doubt any of the others have taken a single physics course. This is a common misconception of first year students at my university. Even if the car were travelling at the speed of light, c=3.0x10*8m/s, then the headlights would still project light which traveled at speed c=3.0x10*8m/s relative to the car. The speed of light is constant in any reference frame, regardless of how fast the reference frame (the car) is moving. This may seem hard to believe at first, as most concepts of special relativity are hard to visualize and are often counter-intuitive to our everyday experience. For another example, if a car were to travel at a speed greater than light (which is impossible, but for the sake of the example), the car's headlight would still project light at a speed c=3.0*10^8m/s relative to the car. Wild, right?