Well you need some new routes for the
Poo Bus I guess?
More seriously... Predict and Provide.
In the UK historic transport policy was to predicted long term car growth and provided the infrastructure to support it. We found that new roads would initially alleviate congestion, but these 'rapidly' got congested too, because of the nature of car use- car use (as in mileage, not necessarily number of trips) will fill up whatever road network there is if there is a net deficit in highway capacity. It doesn't really work, we have to lower car growth instead of cater for it, we don't have the land space. Hence the managed motorways of today rather than extra lanes.
Bristol seem to be trying to 'pull' people out of their cars by making the generalised cost of getting the bus (convenience, stress, time, reliability) lower, whilst also making the GC of private vehicle travel greater.
in my Transport Planner opinion, the only way to make public transport more popular (or rather, used more) is to force people out of there cars- no one wants to get the bus voluntarily. You can have as many soft measures like work place travel plans and things to 'encourge' bus use as you like, but
******** to that, money, laziness and convenience are the big three reasons why people get the car and those have to be removed to make the relative attractiveness of buses increase.