For the engine noise:
* A rumbling truck: This is probably the closest you'll get to a diesel bus engine.
* A large fan: The whirring of a fan can sometimes mimic the hum of a bus engine.
* A heavy object being dragged across a rough surface: This can create a similar rumbling sound.
For the overall sound of a bus moving:
* A train going by: The whooshing and rumbling of a train can resemble the sound of a bus moving down the street.
* A large, heavy object being pushed: If you can find something heavy and bulky, pushing it across a hard surface can produce a similar sound.
For the specific sounds of a bus:
* A horn: You can use a car horn or a similar loud, short blast.
* Brakes screeching: You can recreate this by scraping two metal objects together.
* People talking and moving: You can find recordings of people talking in a crowded space to simulate the sounds of passengers on a bus.
Ultimately, the best way to create a "bus" sound is to use your imagination and creativity! Play around with different objects and sounds until you find something that works for you.