It isn't safe to assume that since your bus is so large it is easily seen by other drivers.
This is not the case. You can't consider yourself safe from any big vehicles as it can be seen by other drivers (in fact, they can be missed too because of their colors).
Let's consider any big vehicles colored with white color or similar color with the surroundings. It can be easily be missed as it get mixed because of their color and the surrounding's color.
So, big isn't safe because of the size. It need to be noticed by other drivers by having distinct colors.