This article aims to introduce an analysis framework to assess and compare different designs of an urban multimodal arterial before their implementation. Especially, the work focuses on dedicated bus lanes and intermittent bus lanes (IBLs), which are compared to the reference case where the buses and cars are mixed in the same flow. First, analytical considerations highlight the influence of buses and IBLs on traffic dynamics in free-flow conditions. Second, the article resorts to an aggregated and parsimonious model to account for both free-flow and congested traffic states. Such a model provides a better understanding and valuable insights on multimodal traffic dynamics on the arterial. To this end, the concept of passenger fundamental diagram is introduced. With this new relationship, efficiency of the global transport system, i.e. behaviours of cars and buses, is assessed and domains of applications of the different transit strategies are identified.