This is partially a question and partially me explaining my understanding of c, frames of reference, and relative motion to see if I have it straight. So, c (the speed of light) is always the same when measured by an observer regardless of the intertial reference frame from which it is measured. This is due to relativistic effects (time dilation, length contraction, and the relativity of simultaneity). As an observer, I would never observe these effects occurring to me, but another observer would observe them happening to me, and these effects would explain my consistent measurements of c, regardless of my relative motion. I hope this is all correct so far. Now please allow me to state this with a practical example: If I move at 5mph relative to the ground I am standing on and I measure light hitting me as I walk, I will measure the light as c, regardless of my walking. This is because the relativistic effects occurring to me (but not noticed by me) compensate for this 5mph of movement exactly. This is the same regardless of whether I walk, run, or dodge, and regardless of the amount of lights sources and their positioning relative to me. Relativistic effect do occur between myself and the ground, but they are negligible at such insignificant fractions of c. My question is: Are the relativistic effects that occur to an observer, and compensate exactly for their movement so that c is always consistent due to the observer's movement, relative to the light itself, the light source, or what? Thank you for your time and energy.