Why do so many riders have the same finish time? They can all cross the line together surely?
It’s impossible for 180 riders to all cross the line simultaneously, of course, so the Tour (and most other stage races) operates the ‘legal fiction’ that all the riders in the race’s main pack cross the line at the same time as the first rider. However, if a split forms and the gap is larger than one second, the next group gets the time of the first rider of that group. Overall, it’s designed to save a mad rush for the line and in most cases it’s too difficult to allocate separate times.