Stages
In most stages, all riders start simultaneously and share the road. The real start usually is some 2 to 5 km away from the starting point, and is announced by the Tour director in the officials' car changing a Start Paddle from the red side to the green side.
Riders who crash within the last 3 kilometers of the stage are credited with the finishing time of the group that they were with when they crashed. This prevents riders from being penalized for accidents that do not accurately reflect their performance on the stage as a whole given that crashes in the final 3 kilometers can be huge pileups that are hard to avoid for a rider farther back in the peloton. The final kilometer is indicated in the course by a red triangular pennant raised above the road.
Flat Stages
The early stages of a stage race are generally flatter. This terrain favors the Sprinters, who often cannot keep up in the mountain stages. Finishing sprints are often very close and exciting in these early stages. These stages sometimes can have long, heroic breakaways by a small group of riders.
Mountain Stages
Mountain stages often bring out the most spectators who line up the roads by the thousands to cheer and encourage their favorite competitors. This is where you see the true grit of the cyclists, the anguish and determination written all over their faces as they stretch to their limits on the long, tough climbs. Sprinters often fall to the wayside here. Their large "fast twitch" muscles do not to get them to the top first. Instead, the King of the Mountains is born, racking up points at the top of designated climbs.
Mountain stages define the true strength and endurance of an athlete. The overall leader of the race will change hands many times during mountain stages.
Time Trials
In an individual time trial each rider starts alone in one-minute intervals. The first stage of the tour is often a very short time trial, known as a Prologue. The purpose of the prologue is to decide who gets to wear the leaders jersey on the opening day, and provide a large and prestigious spectacle for one lucky city. Time trials are crucial stages in a race since each rider rides alone with no help. This real test of fitness and skill has been called "the race of truth". Time trial specialists and the overall winner must do well on these stages. For fans, time trials give an opportunitiy to see each individual rider, the most advanced equipment, and the drama of guaranteed changes in the overall standings.