It could suggest something about your relationship with a person in particular, or with those around you in general. You might also dream of attempting to ride a bus, of chasing after it as it drives down the road. These dreams have a broader meaning which applies to your relationship with society as a whole.
Though the fact that your dream occurred on a bus may seem incidental, especially if it did not feel like the focus of your dream, it is important not to let it fade from your mind and lose what it can contribute to the interpretation. A bus demarks a transitory period and often plays host to contradictory or incompatible symbols. What this means is that you will soon find yourself moving from the influence of one symbol to the other. Buses also suggest dissatisfaction; dreams whose meanings are otherwise uncomfortable or you would wish to change may occur hear.
A bus may also serve as a meeting place in your dreams. If you find yourself speaking with someone then it suggests certain things about your relationship with them. A bus is a place where you find yourself in close proximity to strangers. If you dream of a meeting with a friend there suggests that you feel a distance has grown between you; one you would wish to close so that you can regain the emotional connection you had with them in the past. You might also dream of a discussion with a stranger, whose face has just faded from memory. This suggests a longing, not just for new friends, but for companionship of a particular kind. You find your life hectic and disorganized, you lack a clearly defined role or space or objective and it is the missing provider of those definitions that is symbolized by the stranger. He is the guide you have been looking for.
You might also dream of chasing after a bus. This could mean that you feel somewhat alienated by society; you have difficulty in relating to other people or empathizing with the plight of strangers. You sometimes find society confusing or disorienting and often wish for a moments respite from its onslaught so that you could acclimate; instead it continues the change at a breakneck pace. Chasing a bus is a dream that tends to be repeated night after night; the feelings represented are difficult to reconcile.