The choice between bus and light rail transit: a stylised cost-benefit analysis model

In the last 20 years light rail and tramway schemes have been introduced in many European cities. The effects of these schemes over public transport patronage, and the benefits they have generated, seem to have sometimes been overestimated. The availability of some experiences helps in deriving some reflections about the circumstances in which light rail schemes can be truly convenient compared to bus systems. This paper tries to give a contribution by developing a simplified model to support the choice between keeping a bus corridor or upgrading towards a light rail system. The choice is analysed on the basis of a parametrical socio-economic cost benefit analysis. All the parameters introduced and used for a numerical simulation are discussed and some typical values from the literature are given. On the basis of these values, some feasibility abaci are drawn.