Trends in passenger transport optimisation

The growing number and complexity of modern megalopolises, where several millions of inhabitants request efficient transport services, pose colossal challenges to urban mobility. To capture the ever-increasing demand for mobility without further deteriorating the traffic congestion, it is essential that the resources available are used as efficiently as possible. Besides, the traditional means of transport (train, metro, bus, taxi), each responds to a particular segment of the global demand for mobility. Nowadays, transport planners can take advantage of the progress in information technologies and optimisation methods to design modern services that integrate and coordinate different means of transport. These services are potentially capable of capturing additional segments of mobility demand and, as an outcome, reduce the usage of private vehicles. Building upon these general ideas, a growing number of researchers have studied various forms of transport flexibility as well as the integration among different means of transport. This survey provides an overview of the trends emerging from contributions from the operational research literature on urban passenger transportation. We have analysed the literature according to the dimensions of flexibility and integration of the transport service studied. For each of the application areas identified, we convey the main trends studied, summarise the most relevant solution approaches and outline some open research directions that deserve particular attention.