And, technically, would the color of the light change at different car speeds?

  • 2
    $\begingroup$ If you go really really fast a red stoplight can look green. I wouldn't use that as a defense in court though, since the speeding fine would greatly outweigh the fine for running a red light. $\endgroup$ – Olin Lathrop Oct 21 '13 at 13:33

As far as our latest theories go, the speed of photons is going to be "c" only as they move with speed of light irrespective of your point of observations.

the color factor depends on the original color that was emitted and then the application of dopplers effect for the shift in apparent wavelength and hence color due to velocity of approach of car, however in real life it is insignificant and whatever color is emitted is what we see.

  • $\begingroup$ It is not totally insignificant however for the policeman with the radar gun... $\endgroup$ – Nicolas Oct 21 '13 at 14:13
  • $\begingroup$ I meant for a person driving a car under tedious yet normal condition. Sorry for not elaborating $\endgroup$ – Rijul Gupta Oct 21 '13 at 14:15

Not the answer you're looking for? Browse other questions tagged or ask your own question.