Maybe someone is tailgating it. And it's trying to annoy them by speeding up, then slowing down. There seem to be so many fudge factors in the whole chain of a

Maybe someone is tailgating it. And it's trying to annoy them by speeding up, then slowing down. There seem to be so many fudge factors in the whole chain of analysis we won't have an idea until we can make vastly improved measurements.