From what I can tell, and I ain't no law expert, but if you can prove from a reliable credible source, that your car cannot actually and physically do the speed you are being tried for, then you can get off, as it puts the speed detector device used at a doubt, showing it misread. If the device shows as misread, then it don't matter if you were doing 130 or 135 or whatever speed, as long as the device has misread, you could have been doing 43mph as opposed to 143