The reason that bus flexibility is not an advantage as is often assumed. A tram’s inflexibility is an advantage

It is often assumed that the fact that buses can go anywhere whereas trams are fixed is an advantage.  This is not really the case as the attached picture and article show ( yes this is a rural scene but the same sort of thing happens in Bath and other cities regularly – and we are assuming  a tram line in that direction anyway).

Once a tram has been built you are stuck with it for 40 years and it is in the interests of the operators to run it continuously because the operating costs are very low, and so there are little benefits from curtailing the service. On the other hand buses have very high operating costs so the pressure is to cut out of peak our services and limit service frequency so that the bus is full.

This is why trams can afford to operate at much higher frequencies than buses.  see https://bathtrams.uk/2-minute-tram-service-interval-budapest/

The fact that people begin to realise that tram isn’t going anywhere, then this encourages development of housing and offices along side which creates a positive feedback loop of more development close by and more customers.

They may also decide not to own a car.

On the other hand relying on bus services has been shown to encourage urban decentralisation creating for example housing estates in the countryside that are spread out and then very difficult to service with buses.  So the users all drive to the local town for shopping creating pollution and congestion.

“Villagers braved icy roads and snow to gather at Bath’s bus station to show much they value a rural bus service.

Residents of Tunley, Timsbury, Farmborough, High Littleton, Camerton and Hallatrow all want the 179 restored, claiming they have felt cut off by the reduced service.

Around 60 people came together on Saturday to hand over a 1,000-signature petition to First West of England managing director James Freeman and Bath and North East Somerset Council transport chief Mark Shelford.” https://www.somersetlive.co.uk/news/somerset-news/protesters-march-through-bath-bid-2514127