" You hear stories like that all your life and think: cool, a ghost bus. But now we have to look at this stuff analytically... a ghost bus?! The “ghost” of a motor vehicle? A public conveyance, presumably, which didn't head towards the light, move on to join the choir invisible in... bus heaven, the great terminus in the sky, where all good buses go when they... I don't know, break down, but instead is doomed to … drive eternally the streets of Earth! How can there be a ghost bus?! "

― Paul Cornell , London Falling (Shadow Police, #1)