New computer programmes represent cyclists as virtual riders on a virtual route, which mirror real routes. You can, for example, do a stage of the Tour de France. Data on the route feedbacks to the cycles so cycling is easier or more difficult depending on whether you are going up or down.
Not only that, the programmes network cyclists so they can participate in competitions against each other. Drag is factored in, so cyclists at the front of the virtual peloton have to push harder to get the same distance.