One road, one morning a year. A mass start at the bottom, a timing mat several thousand feet up, and usually a volunteer committee with a folding table and a results sheet going back decades.
The oldest is on Mount Blue Sky, first run in 1962 and named since 1981 for Bob Cook, who won it five times and died at twenty-three. Pikes Peak's race climbs the same road the cars have used since 1916. Haleakalā's Cycle to the Sun runs fifty-eight kilometres from the beach to ten thousand feet, which is the largest paved ascent on Earth done against a clock.
Mount Washington is the strange one. Bicycles are banned from its road every other day of the year, so the race is not the fastest way up the mountain. It is the only way up.