A passenger car unit (PCU) is a way of measuring how much space a mode of transportation, like a car or bus, takes up on the road compared to other modes of transportation.
Imagine playing with toy cars. You have a small toy car and a big toy bus. The big toy bus takes up more space on the road than the small toy car, right? Now, let's pretend that instead of toys, we are talking about real cars on real roads.
A PCU is a way of measuring the amount of space a vehicle takes up on the road based on how big it is and how many people it can hold. A car with just one person in it takes up less space on the road than a bus that can hold 30 people.
So, let's say a single-occupancy car is equal to one PCU. A bus that can hold 30 people would be equal to 30 PCUs because it takes up more space on the road than a single-occupancy car.
This information is important because it helps transportation planners decide how to design and allocate resources for different modes of transportation. If they know that buses take up more space on the road, they can allocate more space for bus lanes or make sure that intersections are designed to accommodate buses.
Overall, the passenger car unit is a way of measuring the amount of space different modes of transportation take up on the road so that planners can make informed decisions about how to design and allocate resources to make transportation more efficient and effective.