speed of light

if any observer moving slower than the speed of light observes the speed of light to be a constant, does that imply that any observer moving at the speed of light observes anything moving slower than the speed of light to be moving at the speed of light, relative to itself?

i.e.:  if light could measure, would it observe a car and a comet to be moving at the same speed?

>>7
Because photons don't have reference frames. There is no reference frame where a photon is at rest.

Asking "What is it like in a photon's reference frame" is a meaningless question, because there is none.