The basic principle to model is simple; here is a very distilled example:
4 people walk up to a ride with a posted 30 minute wait. Two of them wouldn’t wait more than 20 minutes for that particular ride. The other two would gladly wait an hour.
How many people get in line if FP doesn’t exist?
How many people get in line if one person from each group has a FP?
The answers are 2 and 3. You’ll note that 3 is more than 2.
Model out large numbers of people with lots a variance in their wait willingness and you can start to build something useful.
What are the impacts of a FP system?
- The average wait time a person who rides the ride waits overall goes down
- The average time a person in the standby queue waits goes up
- Fewer people are in the queue at any given moment. A portion of the people not in line for this ride will go to other rides, increasing their wait times. This has knock on wait time effects I have not modeled
- Overall, guests are being less efficiently matched with the attractions they most want to do, as tolerances for wait times vary based on interest, but most guests will wait 5 minutes for most rides.
You can read all about it in my book
Fastpass: It’s a Thing That Exists That I Express No Opinion On Except That It Annoys Me To See People Making Demonstrably False Claims On Both Sides.