Out of the 7 colours of the rainbow, violet has the highest frequency and the smallest wavelength. Does this mean that our eye sees it first? If yes, then why? Does it travel at the same or higher speed than other colours? Does the answer to that depend on the medium of propagation? Does the higher frequency decrease detection times, both in our eyes and on camera CCDs and the like?
Nothing like that, all colors (or in physics term, electromagnetic waves of any frequency) travels with the same speed which is denoted popularly by $c$, well the only difference is the scattering in a media. Scattering is inversely proportional to the wavelength, $\Rightarrow$ red scatters less as compared to blue or violet. Therefore red is usually preferred in places where the information is to be sent to a great distance, like the stop signal in traffic. That also explains why the sky appears blue rather than red. So in a way from a distance it is most likely to see red than blue rather than seeing red earlier than blue.