A free program for Android, by Rajesh Khadka.

The Bus driver Undeground app will teach you how to drive a bus. It has very realistic bus-driving physics. It also offers an extreme city environment in which awesome combination of different types of passengers.

The Bus driver Undeground is a simulator app that lets you become a bus driver. In this app, you will need to pick up passengers and safely take them to their destinations. You will also need to follow traffic rules to prevent any trouble while driving to your route. 

Drive carefully to the pick-up spot, open the bus doors, let the passengers board the bus and then drop them at their location. Drive carefully because every time you crash, your bus will get damaged and the passengers will be hurt.