Yosemite in California is one park that requires people driving into the park to book time slots.

https://www.insider.com/national-parks-that-require-reservations-this-summer-2021-6?amp

Yosemite National Park is proposing a fee increase for overnight camping to enable the park to keep up with the rising costs of campground operations. Increased revenue from campground fees will enable the park to better maintain facilities, enhance visitor services, and provide for better resource protection. These proposed fee increases are consistent with other public and private campgrounds within the greater Sierra Nevada region.

https://www.nps.gov/yose/learn/news/yosemite-national-park-solicits-feedback-on-proposed-campground-fee-increases.htm