Well, THAT depends, Ian.
And I say this because, Albert Einstein once explained that in his famous equation, E=mc2("c", of course representing the speed of light) that in the instance such as what you've asked here, the headlight WOULD STILL shine brightly ahead of somebody traveling at the speed of light.
(However, the great genius went on to say that that would ONLY BE the case IF the headlight WERE NOT manufactured by the Lucas Electical Company LTD of Great Britain!!!!)
