Pikes Peak Highway and Summit started a reservation system over the weekend.
Visitors are now required to make an online reservation and pay a $2 fee for two-hour time slots at the summit.
The new system is in place because of an increase of visitors and people spending more time at the top to enjoy added attractions provided when the new summit house opened last summer.
A maximum of 140 visitors can be on the summit at any one time, which corresponds to the same number of parking spaces.