Imagine you are playing with your toy cars on a toy road. You can only have a certain number of cars on the road before it gets too congested and they start bumping into each other. This is kind of like what happens on real roads that cars and other vehicles use.
The same thing happens on bigger roads, like highways or flights routes, where planes fly. Just like the toy road, there can only be a certain number of planes flying on a route at the same time before it gets too crowded and there is not enough space for everyone.
This is called route capacity, which means the maximum number of vehicles or planes that can travel on a certain route at the same time without causing problems. It includes things like the number of lanes on a road or the number of flights that can go in and out of an airport.
Different routes have different capacities depending on how many vehicles or planes can safely and efficiently use them. It is important for transportation planners to understand route capacity so they can make sure everyone can get where they need to go safely and on time.