Newbie Needs help!!!

//tire radius ~ 7 inches
//circumference = 2pir=~43.6 inches
//max speed of 5mph=~88inches/second
//max rps=~19.8

I am more or less trying to make a brake light that will illuminate the brake lights with more intensity if the brakes are slammed. I have an idea, but just cannot figure out how to do the programming!