Originally posted by FabianFnas
That would violate the law of nature, it's impossible.
I think you'd rather mean, near the speed of light.
You would, from your point of view (front seat), not see anything funny. Everything should appear quite normal.
However - from an outside still sitting observer you just have a very high speed (if he sees you at all.
Like he says, AT the speed of light is impossible. Anything under the speed of light and you turn on the headlights, from your point of view, the light goes away from you at the speed of light. The thing is, time has slowed down for you and it looks like the speed of light.
Its going at the speed of light from an outsider POV also.
One thing that happens though, if you point the light away from your direction of travel, it still is emitted at the speed of light but doppler shift will take it towards the red end of the spectrum. Suppose its an ultraviolet light, depending on how close to the speed of light you are, the light going out to your rear may even end up being infrared or longer wavelength than that. It could end up being a radio wave if you are close enough to the speed of light. And conversely, doppler shift will make the beam going in front change to the blue end of the spectrum, it could end up as an X ray if you were close enough to C.