I would like to show a strange feature in my point of view.
I have a lot a large stands in my airport and some of them are connected to airfield shuttles.
When passengers are leaving the airplane, they are dispatched into two shuttles one front, one rear, that is fine.
But when the passengers have to take the shuttle for boarding, all the passengers take only the first shuttle whatever the number of passengers is. The consequence is that the boarding take a long time and delay the flight.
In the following captures, 439 passengers are in the shuttle!
PS sorry for my english.