1. Introduction
Smart, reliable and connected mobility has been a long-standing goal of transit services. According to the definition provided by [
1], Mobility-as-a-Service is a user-centric, intelligent mobility management and distribution system. Considering social inclusion and the sustainable development, mobility is an important issue of smart cities, which are networked places deploying Infocommunication technologies and Internet of Things (IoT) into each activity [
2,
3]. Intelligent mobility [
4] has the potential “to increase mobility, improve safety, and enhance user benefits whilst simultaneously reducing pollution, consumption, and congestion”. Historically, mobility has been viewed largely as a product in the form of displacement. Increasingly, mobility is approached as a service. Resulting in a step change in mobility, intelligent mobility requires the integration of different technologies, services, and products. It is the convergence of digital industries, transport infrastructure, different modes of vehicles, traffic management and end-users, to provide innovative services. And integration is one of its themes [
4]. For completing the smart traveling, privately owned cars and traditional public transport are no longer the only mobility options available to travelers. Their chances to access to different types of mobility, i.e., intelligent mobility, are being broadened by new mobility services and innovations within existing mobility options. “Mobility as a Service” (MaaS) is one of the novel mobility concepts that could assist in achieving integrated, door-to-door, and seamless mobility, building on the shared mobility services provided by the various shared modes e.g., car-sharing, bike-sharing, especially in combination with traditional public transport, and developments in Infocommunication technologies [
5].
In form, in the new digital age MaaS is an online, web, and smartphone apps-based mobility on demand (MOD) and customised service, e.g., ridesharing, which connects the trips of passengers and instruct the passengers to combine their trips via a single interface, resulting in that a single vehicle can accommodate more than one passenger at a time [
6]. This means that the customer focused MaaS model can provided point-to-point and combined transport service through a unified gateway via smart technology. In nature, MaaS is an evolutionary continuation of transport integration, instead of new or revolutionary transport technology [
7]. The key concept behind MaaS is to offer travellers mobility solutions in line with their travel requests. In operation, the MaaS platforms can provide an intermodal journey planner (i.e., providing combined services of different transport modes: rail, bus, car--sharing, car rental, metro, bike-sharing, taxi), a booking system, easy-payment methods, mobility packages and real time information [
8]. Aiming for smart, green and integrated transport, the European Commission located Maas within the area of Intelligent Transportation Systems (ITS) in its H2020 Work Programme. Thus, ITS lays the foundation for MaaS, while MaaS is the driver for smart and seamless travelling. The prospect of MaaS is bound to the need for end-user centric integration and leads to a favorable response from mobility system users with a broad range of individual priorities towards smart and seamless traveling [
7].
Increasingly, with the information and infocommunication technology support, seamless on-demand and end-to-end mobility at the touch of a button is becoming a reality. Meanwhile, supply management innovation towards smart traveling should be encouraged accordingly. As one might expect, these developments, e.g., MaaS, will result in significant changes in the mobility supply/value chain, and established transport players will have to think carefully about their desired position in these new ecosystems, with new players entering the transport industry [
4]. [
5] highlights that it is important to study not only MaaS as a whole, but also its component elements, intermodal journey planners included. In the study of [
9], it is assumed that MaaS encompass only public and shared mobility services, ignoring the private transport. In this study, we focus on the infrastructure and shared/public vehicle integrations and concern the intermodal journey planning for the MaaS platform, facing the challenge of matching multiple links of different traveler paths to multiple transport operators, which can be pre-purchased by the customers through the mobility package tool for a long period of time as one product. In the MaaS market, as one of the core service providers, the transport operators need sufficient incentives to involve the service supply chain network towards the links on the trip chains of the travelers. According to [
10], without a foundation of effective supply chain organizational relationships, any effort to manage the flow across the supply chain is unlikely to be successful.
According to the level of MaaS integration [
7], in this study, we assume that both the operational integration, i.e., interchange penalties are low and door-to-door journey experience is seamless, and the informational integration, i.e., journey planning and execution information for alternative modes is offered through one interface, are available. In other words, in the form of an APP, MaaS can enable the multi-modal planning with the ability of digital connectivity. And service providers have access to timetables, real-time traffic and transport data, as well as the traffic control. As Maas is acknowledged as a socio-technical phenomenon [
11], a hybrid modal model which can align with MaaS as a mix of point-to-point and ‘point-via-point(s) to point’, i.e., the service supply chain network tailored to maximizing the seamless delivery requirement towards smart travelling, is worth investigating in details, and this study is related to technology integration and human travel behavior. The intelligent mobility service supply chain network motivated by MaaS for seamless travelling is a multimodal transport network, in which a variety of companies and transport modes operate, to better adapt to the geographical - temporal variations of demand density. In this network, it is possible there are multiple links, i.e., served by more than one company or mode, between two stops-nodes. Meanwhile, a user can seamlessly experience the services provided by different suppliers in consecutive links for fulfilling the whole travel. Finding equilibria in the transport markets that lack a central authority of control is a challenging task.
In order to be able to capture the complex interactions among decision-makers, it is essential to model and analyze the supply chain network with a holistic, system-wide approach. A MaaS provider acts as an intermediary between the user and the transport providers. Modal integration in the context of MaaS can help ensure that the transport system is network-wide efficient, instead of just efficient within each mode or operator individually [
12]. On the other hand, it exists a risk that MaaS may induce an adverse effect, i.e., leading end-users to give up public transport, instead of their cars, in favour of ride-sharing trips [
13]. However, in terms of sustainability gains, any shift from public transport to car-centric solutions is not in line with what MaaS is set to achieve [
14]. These also testify the necessities of the synergetic design of mobility service supply chain network to provide more flexible transport service for seamless travelling, through spatial and temporal integration among fixed and demand-responsive transportation. However, there is little systematic methodology to guide this kind of design and integration of future-generation transit systems [
15], combing fixed-schedule and demand-responsive services. With this preliminary study, we aim to fill this gap. MaaS is not a ‘one size fits all’ solution for all regions [
16], so we explore its urban-wide implementation in this study. Furthermore, to be more realistic, the value of MaaS is not in competing with and beating the convenience of the private car, but in creating a multimodal smart/seamless travel option, even a more livable, socially inclusive and sustainable futures towards smart city.
We contribute to this study in several ways.
Section 2 conducts an extensive literature review on mobility behavior and demand pattern of Maas end-users. These are crucial to better integrate different transport modes, manage demand and supply, and provide better access. In
Section 3, the intelligent mobility service supply chain network in the context of MaaS is interpreted from four perspectives, i.e., mobility service taxonomy of MaaS, aims of intelligent mobility service supply chain network, urban rail transit (URT)-centered alternatives for integrated multimodal journey, and node member imperatives.
Section 4 proposes the synergetic design of intelligent mobility service supply chain network, including: (i) multi-tier closed-loop structure of the intelligent mobility service supply chain network, (ii) key nodes identification for the physical multimodal transport network in the supply chain, (iii) synergy principle, (iv) temporal splitting approach for coopetition, (v)synergy measurement. Maas is especially instructive in efficiently obtaining not only operational but also demand data, which can promote integrating models that consider all transportation modes, involving all parties and stakeholders (users, planning agencies, operators and policies). In nature, the proposed intelligent mobility service supply chain network is a mixture of planning and responsive transport system. In
Section 5 we make the conclusion remarks.
2. Analysis on mobility behavior and demand pattern of MaaS end-users
Understanding traveler behavior is crucial to better integrate different transport modes, manage demand and supply, and provide better access. The theoretical model of complex travel behavior can be classified into the following two categories [
17]: (i) trip-based travel demand models, (ii) activity-based approach. OD flows are an aggregated representation of individuals activity-travel chains [
18]. To improve computational efficiency, generally the locations of the individual activity are aggregated into zones. The opinion that the demand and supply of future mobility options will both have to be considered for intelligent mobility [
4] should be always held in the related research. Under the background of emerging ‘Sharing Economy’ concept, ([
4] Transport System Catapult, 2015) identified a number of travellers key needs, pain-points, and attitudes, and clustered them into a ‘Hierarchy of Traveler Needs’ consisting of three areas from the highest level to the fundamental level: enabling lifestyles, enhancing end-to-end journey, and removing pain-points. For the highest level of enabling lifestyles, it aims at improving mobility fit, i.e., focuses on the problem how intelligent mobility might increase access to better mobility options. For the middle level of enhancing end-to-end journeys, it aims at improving motility choice, i.e., focuses on the problem how intelligent mobility might engage travelers to consider better mobility options. For the fundamental level of removing pain-points, it aims at improving mobility experiences, i.e., focuses on the problem how intelligent mobility might improve mobility options and remove pain-points.
As decision-makers need to understand how the travelers respond to a particular supply that is represented by the MaaS services, [
19] identified the behavioral patterns of populations of travelers in the context of MaaS, by creating a methodology able to generate the artificial societies. [
9] collected and analyzed the novel data on user preferences for MaaS plans in London and Manchester by combining quantitative and qualitative methods, so as to get insights on what type of MaaS plans individuals would favour. Regardless of the heterogeneous end-user preferences, their choices of routes and vehicles/modes are mostly based on travel time, travel cost, comfort, less transfer, and security, etc. So far, some human mobility patterns have been discovered, e.g., the power law and the exponential law. With Maximum Likelihood Estimation (MLE) and Bayesian Information Criterion (BIC), [
20] leveraged three metrics to analyze the human mobility patterns in two real subway and taxi datasets i.e., trip displacement, trip duration, and trip interval.
[
21] showed that the mobility service application (MSA) was mostly used for regional and local public transport trips, and the users stated that the MSA made it easier to travel by public transport. [
22] showed that psychological needs play a crucial role in the acceptance of MaaS. Besides perceived extrinsic benefits, hedonic motives and habit-based heuristics, usage related self-perceptions (feelings of autonomy, competence and relatedness to an associated peer user group) should be considered as higher order motivational goals that might affect MaaS adoption intention.
By collecting data through user-preference surveys and semi-structured interviews, [
23] clustered five attributes of integrated public transport system, i.e., network integration (a fundamental attribute perceived by policy makers and users), fare and ticketing integration (valued by policy makers and frequent users), information integration, physical integration of stations, and coordinated schedules. In nature, the mobility service in the MaaS still belongs to the kind of public transport, so the abovementioned five attributes are adaptable to the synergetic design of intelligent mobility service supply chain network, towards seamless travelling and integrated multimodal journey planning. And it can help make public transport a preferred mode, instead of a choice. Particularly, MaaS promises to better fulfill real traveler needs than conventional public transport [
24], e.g., flexible and integrated transport on-demand, and human centered service design.
In order to travel from one point to another using MaaS, the subscription activities of the end-user in the MaaS platform involve to generate and submit traveler profile, generate and submit travel requirements, receive and select generated trip, receive and select mobility package, receive the paybill and pay subscription. [
25] identified five core themes as critical determinants underpinning MaaS acceptance and success: car dependence (i.e., modal shift, convenience, enjoyment, morality), trust (i.e., trialling, efficiency, capacity, technology, cyber security, digital readiness), human element externalities (i.e., discourtesy, negligence, danger anticipation, abuse and disobedience), value (i.e., accounts and feedback, application and integration, breaking habits, analytics, leisure and tourism, level of service provision), and cost (benchmarking versus status quo, time, incentives reliefs and motives).
It is recognized that tailoring of the traffic offerings to satisfy the MaaS end-user’s need is the key success factor in changing the travelers’ behavior, i.e., end-user attitudes and behaviors matter much to attract them to shift from the traditional or private travel modes. The MaaS end-user perspective emphasized by the European Mobility-as-a-Service Alliance is to offer the users tailor made mobility solutions based on their individual needs, e.g., in accordance with their travel goals and trip purposes, with easy access to the most appropriate transport modes or services. As analyzed by [
11], the typical travel goal for the citizens is to bridge the distance between two geographical points, or just for the experience of traveling; while the trip purposes, i.e., why the distance needs bridging, can be sorted into private and professional purposes. The private trips are usually motivated by concrete goals, e.g. shopping, dropping or picking up kids, or pure leisure, e.g. visiting an interesting place. Professional trips are usually job or study related, which can be divided into frequent work commute and infrequent business trip. On the other hand, the combinations of private and professional trips are also common, e.g. shopping after work.
According to the definition of [
26], the end-users of MaaS are the kind of typical planning passengers, who have a pre-trip choice of departure time and stop via subscription. Moreover, the planning passengers can be categorized as two types: (i) those with the desired arrival time at destination and (ii) those with desired departure time from origin [
27]. In the context of MaaS, the subscription behavior in just one user interface plays an important role from a user-centric view on MaaS [
11], which adds the possibility to the end-users to select a route (from door-to-door based planning to journey), book (the actual agreement on a mobility service) the service and pay (paying the fare price to the mobility provider, trip based or time based) it, and particularly makes the passenger flow more predictable and controllable, e.g., to implement the incentive-based Active Demand Management (ADM) strategy. Meanwhile, for mobility behavioral analysis/modelling in the context of Maas bundle design [
28], it is necessary to incorporate sensitivity to information presentation, dynamic information modification during a deliberation process, the framing (e.g., loss, gain) effect of historical preference, the impact of precedent decisions, and time pressure levels [
29].
6. Conclusions
In conclusion, we provided important insights about the MaaS-motivated synergetic design of intelligent mobility service supply chain network towards urban- wide smart & seamless traveling and integrated multi-modal journey planning. This is the first endeavour that explores the mechanism of supply chain network to smooth the multi-modal mobiltiy service via MaaS. In this context, MaaS plays the roles as the mobiltiy intermediary and mobility service manager, e.g., intermodal journey planners. To enhance the mobility service level, i.e., seamless and smart travelling, this paper considers both the transport operators from the supply side (i.e., mobiltiy service type of MaaS, journey alternatives and node member imperatives) and end-users (i.e., mobiltiy behavior & demand pattern) from the demand side jointly in a multi-tier closed-loop supply chain network. If the principle of MaaS can be interpreted as: Blockchain + Transport = MaaS, then the intelligent mobility service supply chain network proposed in this study can be interpreted as: Internet of Service + MaaS = Internet of Transport Service. The intelligent mobility service supply chain network can be cooperation-dominant coopetition or competition-dominant coopetition, when it can ensure that no player in a coalition has incentive to generate a higher payoff by forming another coalition, it achieves the synergetic stability conditions. At this status, it also can perform the typical synergy effects with higher synergy degree, i.e. 1 + 1 > 2.
By far there exists at least four main providers of commercially MaaS bundles with different levels of integration from price bundling to product bundling [
28], e.g., Whim (an international provider rolling out in Finland, Netherland, UK, Austria, Japan and Singapore), UbiGo (Sweden), Stadtwerke Augsburg (Germand) and zengo (Switzerland). Most of the bundle designs from prior peer-reviewed academic stated choice studies and commercial trials can be mapped and compared along the dimensions of modes, metrics, geography, market segment, subscription cycle, discounts, caps to the subsidized use of modes, non-transportation add-ons, customizability, and roll-over options for unused budget, but few of them has focused on the intelligent mobility service design from the perspective of trip chains using the synergetic mechanisms of supply chain network, which is one of the key business for any Maas bundles. We developed the hybrid synergy mechanism for the intelligent mobility supply chain network, i.e., multi-tier closed-loop structure, key nodes for the physical multimodal transport network, synergy principle, synergy form, synergy content, and synergy measurement. Particularly, this intelligent mobility service supply chain network structure can bridge the gap between weak-demand periods and public transport [
54]. By taking URT as the backbone or focal members, the proposed intelligent mobility service supply chain network can reduce the risk that MaaS may induce the adverse effects [
25], e.g. traffic congestion, air pollution. Moreover, the MaaS-motivated synergetic design of intelligent mobility service supply chain network towards the seamless travelling and multimodal journey planning can be more instructive for the promising during and post-pandemic transport mode.