Shared Mobility Systems

Shared mobility systems for bicycles and cars have grown in popularity in recent years and have attracted the attention of the operational research community. Researchers Laporte, from the HEC Montréal, Meunier, from the Université Paris Est, and Calvo, from the Université Paris, have investigated several problems arising at the strategic, tactical and operational levels. Their survey paper classifies the relevant literature under five main headings: station location, fleet dimensioning, station inventory, rebalancing incentives, and vehicle repositioning and open the way to several practical and research questions.

In fact, the world of transportation has witnessed a mini-revolution in June 2007 with the launching of the V ́elib’ bicycle sharing system in Paris. Initially 20,000 bicycles were deployed over 1,500 free-access stations. In the first year 200,000 users registered and 26 million bicycles were rented. Since then, the phenomenon has known a considerable growth. While V ́elib’ was not the first bicycle sharing system, it was the first one of any major significance. Public bicycles were first introduced in Amsterdam in 1965, within the so-called white bicycle plan, but most of these earlier systems ended up in failure because of theft and vandalism. Bicycle sharing really took off with the advent of communication and information technologies which allow for automatic billing and monitoring. Today there are currently over 7,000 bicycle sharing systems in the world, involving over 800,000 bicycles.

In parallel, a number of car sharing systems have also been put in place. Again, the first one (Autolib’) was set up in Paris in 2007. Currently the world’s largest car sharing networks totally mora than 2 million of users and almost 25.000 vehicles in several Navigant Consulting predicts that the number of car sharing members will grow over 12 million worldwide by 2020 and will generate in excess of US$ 6 billion in revenue. The growth and expansion of car sharing systems will be fueled by high energy costs, limited and expensive parking, improved technologies and increased demand for personal vehicle access in developing countries.

The central problem faced by shared mobility systems operators is to maintain an adequate number of vehicles in every station. Indeed, too large a number can impede the return of vehicles whereas too small a number may translate into lost demand. Locating stations, choosing the number of vehicles per station, moving vehicles between stations, inciting users to change their destination, are all managerial decisions guided by the need to provide a good quality of service, at both end-stations. Providing effective tools to support these decisions constitutes an important motivation for researchers in this new field, especially for operational researchers. However, shared mobility systems have also attracted the attention of researchers in other areas, such as transport economics, urban planning, sociology, and data mining. Data mining actually plays an important role in determining the values of the parameters in most of the operational research models. The purpose of the researchers was to survey the main operational research issues arising in shared mobility systems as well as the methods that have been proposed to address them. They examined station location, fleet dimensioning, station sizing, rebalancing incentives, and vehicle repositioning. For each of these topics, they provided an overview on the literature and describe one or more solution approaches that seemed important to them.

According to the researchers, some interesting combinatorial questions remain to be investigated. For example, determining the optimal inventory level at each station is an important aspect of the rebalancing problem that has not yet received much attention and should ideally be studied within a theoretical framework. On the methodological side, the design of exact algorithms for the multi-truck rebalancing problem has not yet been investigated and seems rather difficult for instances of reasonable sizes.

This is a summary of the article “Shared Mobility Systems”, originally published on the Journal 4OR – Vol. 13, 341 – 360 (December, 2015).

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