You wouldn't believe it.
Question to Bristol's Cabinet Member for Transport: of bus passengers travelling into the city, what proportion continue their journey beyond the central area on a) the same bus, or b) by another route?
Answer. Don't know. No idea.
Supplementary question: Wouldn't it be a good idea to find out? It would help, for instance, with deciding what the need is for better interchange facilities.
Supplementary answer: Maybe. We could ask the bus operators, but even if they know and they tell us, we couldn't tell anyone because of commercial confidentiality.
How on earth can we ever get a fit for purpose public transport network if we can't even find out where people actually travel?