Mobility is an important component of all human activity, ensuring the access of citizens to exercise their social rights and the capacity to partake in productive activities. In an urban environment, with higher population densities and levels of economic activity, mobility drives economic development and contributes to social equity. Yet, for all the benefits it confers on citizens, transport activity is also seen as a major urban challenge due to the environmental and social impacts it often engenders, especially in highly motorised and car dependent regions. Increasing purchasing power, which in many countries has surpassed the increase of transportation costs, and technology development has lowered the relative costs of cars just as disposable income has increased. Even in developing countries, where household income is lower, motorisation levels are rapidly increasing, though their use is still largely below walking and public transport. Single-occupancy car use generates individual and collective benefits but these are eroded and, in some cases, obviated by environmental impacts, loss of transport system efficiency due to congestion, social inequity and exclusion, as well as road crashes and strong dependence on fossil fuels. Against that backdrop, any effort to provide high quality transport options for citizens must incorporate an understanding of the underlying factors that drive transport decisions and underpin the dominance of the private car. The private car presents a clear advantage over other transport options in three key areas: flexibility, comfort and availability. These characteristics of the private car may significantly blur the perception of other modes and explain the attraction of the car as an attractive choice to many individuals and households. Typically, the response to the negative impacts of car-dominated transport systems — when there has been one — has been to promote public transport and, to a lesser extent, walking and cycling. Contrary to the latter two, deploying ever more extensive and good quality public transport comes at a heavy cost, especially for those services that are poorly used outside of peak periods or core parts of urban areas. Despite the active promotion of public transport (PT) networks, public transport continues to lose market share to private vehicles in most developed economies. Three main approaches to mitigating urban mobility problems have been proposed: influence demand to reduce travel needs (avoid), promote more sustainable transport options (shift) and deploy better technology and reorganise supply (improve). From a technological perspective (improve), the efforts in the last decades have concentrated on the development of cleaner energies and more efficient vehicle engines. Other significant developments were obtained through the reduction of the environmental impact of transportation infrastructure. These measures tend to be effective in the short term; however, the overall impact on the system in the long run might be negligible if transport demand continues to increase at the same pace. From the avoid perspective, some policies have been recently designed to act on the supply side, not only promoting tele-activities but also providing more efficient infrastructure and land-use distribution. This concept emerged in the US during the last few decades under the designation of Transit Oriented Development (TOD), where the objective is to develop “Smart Growth” areas with mix land-uses and that are compact and walkable, usually around rail stations. This new urban development paradigm aims to promote accessibility to a wider variety of activities, encouraging walking and the use of more sustainable transport options instead of single car use. This is a promising approach but one for which the long-term wider impacts are uncertain. Shifting demand towards more sustainable transport options has shown to be promising as well, perhaps more so than some of the other approaches outlined beforehand. Several cities have sought to promote more efficient and rational use of existent transport systems. These Travel Demand Management (TDM) approaches introduce or promote more efficient transport options or create behavioral and financial incentives towards more efficient mobility. There are many different measures that can be used in TDM and some of them have already been successfully implemented: moral campaigns (e.g. eco-driving); the promotion of non-motorised transport modes; or parking policies aiming at reducing cars in city centres and, congestion charges in London and Stockholm. The promotion of Intelligent Transport Systems (ITS) may also enhance the efficiency of the transport system. Recently, the promotion and integration of shared transport options, within a so-called shared economy paradigm has emerged. This new mobility paradigm may represent an interesting option to better manage transport in cities. This concept has been in discussion for several decades but only in more recent years, technology has evolved sufficiently and its key instrument - the smartphone - spread enough across the population to allow for the shared mobility market to gain some scale and become more viable. This new approach to demand management aims at exploring mobility resources more efficiently, while preserving good levels of comfort and flexibility normally associated with the private car. The proposed shared modes explore how to increase low levels of private vehicle use in both space and time since cars are typically used during peak hours and rarely for more than 10% of the day. They also display very low levels of occupancy. Despite this, they are highly valued assets — so highly valued that households put up with the expense and low usage in order to derive specific benefits relating to comfortable, door-to-door and schedule-less travel. This low efficiency at the personal level is replicated at the social level with congestion and emissions exacerbated by the quite low occupancy levels of private cars. Could this inefficiency be reduced while retaining these benefits? The traditional shared mobility market tries to explore these two dimensions (sequential or parallel share of vehicles) by segmenting supply to improve demand satisfaction. Two main transport options have been widely explored: carpooling (space sharing among a group of friends) and carsharing (time sharing). Additionally, two other shared transport alternatives that further explore this spectrum of shared mobility efficiency: ridesharing or Shared Taxis, which represent an expansion to the existing taxi system where different passengers or parties share the same vehicle for parts of their rides, and on-demand minibus services, that expand or replace the regular bus concept beyond fixed routes and fixed schedules to improve public transport provision efficiency and efficacy. Both alternatives explore time and space sharing solutions. With the arrival of ubiquitous internet access and dedicated app-based services, carsharing has quickly grown in popularity and sophistication and numerous successful services have been deployed around the world. At the same time, there has been an analogous development in terms of technological sophistication with ridesharing services, especially for app-based on-demand services. These can take the form of taxi-like services or peer-to-peer real-time ridesharing. As with app-based carsharing, these forms of ridesharing have proven to be tremendously popular and pioneering companies in this field have been very successful. Several studies have explored through simulations the role of shared mobility services either as additional service in the mobility market (Martinez et al., 2015), or by fully deployed systems that would replace all motorised mobility in a city (Fagnant and Kockelman, 2014; Zachariah et al., 2013). Our work is based on a simulation platform that allows the exploration of different shared transport scenarios that preserve the behavioral preferences and citizens’ mobility profiles of today. We develop a comprehensive simulation model that is able to reproduce as accurately as possible the interaction between users and shared mobility options in a realistic transport network and urban context. This system allows insights for understanding what type of performance should be expected from the implementation of different mobility systems. We chose to develop this model on the basis of agent-based techniques given the difficulty in representing the complex spatial-temporal relation between vehicle supply and passenger demand by other types of aggregated and disaggregated simulation methods. The usefulness of agent based models has been well demonstrated in several areas of transportation analysis (Arentze et al., 2010; Davidsson et al., 2005; Roorda et al., 2010; Tang et al., 2012; Vliet et al., 2010). These models allow a detailed representation of the interactions of multiple agents in a realistic synthetic environment where the intent is to re-create and predict the appearance of a complex phenomenon, which is the case of the mobility market. The objective is to obtain high level indicators from describing accurately the lower level reality of shared mobility supply interacting with current mobility demand. This report constitutes an update of the Corporate Partnership Board report published in May 2015, incorporating not only joint consideration of two modes of demand-responsive services (Shared Taxis and Taxi-Buses) but also significant improvements in the algorithms used for matching demand and supply and a much wider exploration of the results of that process in terms of the indicators produced for analysis of its quality of service, productive efficiency, cost competitiveness and equity of accessibility. The main source of the very large gains of efficiency and accessibility obtained in the model runs for this work, as reported below, is the combination of the demand-responsive service with the shared used of the vehicles. Therefore, this report investigates those elements principally and leaves aside, for the time being, any further investigation of automated driving and carsharing services that were included in the 2015 report. (Author/publisher)
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