I've inadvertantly come to a scientific conclusion.
It is thus:
People that have a yellow "Support Our Troops" magnet on thier cars/trucks are PHYSICALLY INCAPABLE of driving up to or above the SPEED LIMIT!!
It seems this seemingly innocent magnet is some SUPER VORTEX OF SLOWNESS, and renders the driver's of said cars feet inoperable. When this happens, they apparently can only "rest" said feet on gas pedels, making thier speed an always consistant 45 MPH!!
I swear. Test my theory out. I am a genious...