When bus stops, at first the center door is opened for passengers to get off the bus. Then with a few seconds delay the front door is opened for the passengers to get into the bus.
In spite of rush hour the bus adheres and makes sure to stop in the bus stop. At the same time how much ever people are in urgent all the passengers will fall in a line and get into the bus one by one without pushing each other.
Almost in all major cities and towns where ever there is a multi lane system the left most lane will be パス専用 - basu senyou means "Exclusive lane for bus" or in some places it will be バス優先 - basu yuusen meaning "Priority for bus". This is to make sure for those who use bus the traffic is as smooth as possible.
In most of cases, you can correct your watch by the arrival of the bus and the time table, they are that punctual.
Disclaimer: This is my personal observation in Japan for about 14 years, you may think in other countries the buses are managed much better than Japan. Good to know about that.
