I wish there was a more ominous image in the mirror that makes you look like you are running.. like the police (not that I want them after you, but they could've been on the road in another emergency), or a dinosaur toy strapped to your car to get the reflection in the mirror..
just musing.
I like the clear quality of the shot, and the "woosh" feeling it gives me.
Really a simple idea, and I think you did this well. I do think the crop should of been tighter to focus the eye more on the mirror. True the background is part of the speed, but there is a large void/empty space. Not too shabby.....good shootin'!!!