Not clear what you mean but i expect that you're talking about a GPS position finder that will show the first one over the line in the races. As well as show the time delay between a breakaway and the peloton. These things pretty accurately give position and speed from which you can calculate time differentials. But as you can see, this is not 100% accurate because time differentials are all screwed up in uphills and downhills because of the present speed of an individual.