If you are in the car, the headlights would look normal. If the car is driving towards you, the light would be blue shifted. If it is driving away from you (I guess you would be seeing the taillights), they would be red shifted. That is what happens when you look at the light from distant galaxies. Because the universe is expanding, the galaxies are moving away from us rather fast. Because you know the emission spectra of the stars in them, you can calculate the red shift, and that tells you how far away the galaxy is.