I never catch the field until 15-20miles and in a short 12 mile race, I'm screwed.
Riders always ride faster during the first miles of the race because their legs are fresh.
Some people think the last third of the race is fastest because the pace picks up and they seem to hurt more than at the start. This hurting more is because they are tired and not because the race is faster. Common sense should tell you that it is not possible for the last third of a race to be as fast as the first third because of fatigue. Faster always means more speed and requires speed work. That is just common sense.