[iso1631]

Vast majority of bus lanes are a dedicated lane down a multi lane road for pushbikes, buses, motorbikes (and for some stupid reason taxis). It effectively allows a bus with 50 people on to jump the queue.

In this particular case it is a "bus" only lane over the river, the diversion for non buses is less than a mile, and far less for almost any actual car journey (given that if you just wanted to cross the bridge you'd walk.

The far more problematic issue in Bath is the continued closure of Cleveland Place due to the bridge falling to bits.