Okay kiddo, let me explain passengers per hour per direction (PPHPD) to you.
Imagine you are in a big city like New York or London and you want to take a train or subway. Now, there are many people like you who want to travel in different directions at different times. To make sure that everybody gets to their destination on time, the transportation system needs to carry a certain number of passengers per hour in each direction.
Now, if we count how many passengers are traveling in one hour in one direction, that is called PPHPD. It helps us understand how many people can travel in a specific direction in one hour.
Think of it this way. If you and your friends are playing a game and you can each carry one ball at a time, and you want to move 50 balls from one end of the room to the other in one hour, you need to pass the ball to each other 50 times in one hour. So that means you and your friends can carry 50 balls per hour in one direction.
Similarly, when we talk about PPHPD, we are counting how many people can travel in a certain direction in one hour. This is important information for transportation planners to make sure that there are enough trains or buses to accommodate all the passengers who need to travel in a certain direction in one hour.
Did that make sense, kiddo?