This chapter presents a comprehensive literature review aimed at examining the environmental impacts of high-speed rail (HSR). The findings are organized into two frameworks: one addressing the environmental impact of HSR operations and another addressing the lifetime environmental impact of HSR investments. These frameworks illustrate the factors influencing the environmental impact of HSR and the mechanisms through which HSR affects the environment. Approximately 50 % of the studies assessing the lifetime environmental impact and 15 % of those focusing on the environmental effects of HSR operations conclude that the overall environmental impact of HSR is not positive. This is noteworthy since rail travel typically generates lower emissions per passenger kilometer than other transport modes, and policy-makers often consider HSR an environmentally friendly mode of transportation. Furthermore, HSR's environmental impact varies considerably based on several factors, including the economic and industrial characteristics of regions connected by HSR and the specific attributes of their existing transport systems. However, the review does not show any clear trends regarding the nature (positive or negative) and magnitude of the environmental impact associated with these factors. It highlights the importance of conducting thorough environmental evaluations on a case-by-case basis when considering HSR investment due to its environmental advantages.

Urban Air Mobility (UAM) systems offer a three-dimensional transportation alternative by using low-altitude airspace, with the potential to reduce travel times and improve access to mobility in regions underserved by current transportation systems. To support efficient design and operation of UAM systems, we develop an integrated optimization framework in response to three interrelated challenges: (i) land use, aeronautical feasibility, community acceptance and other factors that restrict the number of potential locations for vertiports, (ii) bidirectional demand–supply interaction that needs to be considered, as the level of service influences demand for UAM and operators adjust the level of service in response to demand, and (iii) strong interactions between strategic decisions on the distribution of ground infrastructure, tactical decisions on eVTOL fleet size and operational decisions on dispatching and repositioning. Analyzing the decisions in isolation can lead to poor estimates of the overall system performance. The framework consists of (1) a knock-off criteria analysis model for the identification of a realistic set of candidate locations for vertiports, (2) integer programming models in which strategic, tactical and operational decision levels are modeled, and (3) pre-processing techniques to generate near-optimal solutions for real-world instances. By applying the framework in a large-scale real-world setting in the Île-de-France region, we demonstrate complex interactions between strategic, tactical, and operational decision levels and customer demand, revealing various trade-offs between operator profit and traveler generalized travel costs.

Vehicle-to-grid (V2G) could help balance and regulate the electricity grid. While research papers have focused primarily on the technological potential of V2G services and consumer adaptation, the institutional barriers obstructing the industry from implementing V2G are hardly researched. This study, therefore, explored these institutional barriers using grounded theory and stakeholder interviews. The results showed an array of barriers related to communication standard ambiguity, non-harmonised and undefined network codes, charging standard ambiguity resulting in uncertainties and financial risks, and conflicting stakeholder needs about who should control V2G operations. We conclude that large-scale adoption of V2G in Europe is hindered because it is unclear to the actors involved how to become ”V2G-ready”. This lack of clarity results in an innovation that is in a wait-and-see phase. We give practical recommendations to potentially become V2G-ready and for further research.

Integrating bike-sharing programs with public transport enhances accessibility and car-independent mobility, yet a comprehensive societal cost-benefit analysis of this integration remains scarce. This study addresses this gap by conducting an ex-durante analysis of the OV-fiets program in the Netherlands, a station-based round-trip bike-sharing system designed to improve last-mile connectivity for train commuters. The analysis reveals that in the average (balanced) scenario, the net present value (NPV) of the OV-fiets scheme is positive, with a benefit-cost ratio (BCR) of 1.5. This indicates that the scheme has benefited the Dutch society over the 20-year period (2004–2023). In the pessimistic scenario, the NPV remains slightly positive with a BCR of 1.1. This implies that even under the least favourable conditions, where high costs and low benefits are assumed, the scheme still slightly exceeds the break-even point. Conversely, in the optimistic scenario, the BCR rises significantly to 2.4. Primary benefits include enhanced accessibility, reduced road congestion, and improved health outcomes. This research underscores the considerable societal value of the OV-fiets program in the Netherlands, warranting continued investment in the program and emphasising the need for ongoing bicycle safety measures and infrastructure improvements. However, OV-fiets might be successful in the Netherlands; our analysis also shows that copying it into other contexts is not straightforward. The seamless integration of bikes with trains is crucial, and the operators should be able and willing to accept operational losses.

High-speed rail (HSR) is frequently seen as a promising alternative for long-distance travel by air and road, given its environmental advantages whilst offering a competitive level of service. However, a European HSR-network is yet to be realised, with the current state amounting to a patchwork of poorly connected subnetworks. Consequently, this results in a suboptimal performance from a user, operator and societal perspective. We present a customised version of the Transit Network Design and Frequency Setting Problem (TNDFSP) for the long-distance transport context and HSR in particular. We apply an adapted version of a heuristic solution approach to analyse the users’, operators’ and societal performance of a European HSR-network by conducting an extensive series of experiments to test the network's performance under various policy priorities and HSR design variables. Our experiment results show that designs resulting from the consideration of externalities yield more extensive networks with larger coverage and modal shifts. For such networks to materialise, high public investments are needed. The obtained network designs contain four different line types, exhibit spatial disparities in network density, and allow for the identification of potential hubs and critical infrastructure. The strong network integration with overlapping and border-crossing lines of substantial lengths highlights the importance of cross-border cooperation and rail interoperability. We hope our findings will contribute to the ongoing public and professional debates on designing an attractive and competitive European HSR-network.

A restructuring of the current mobility and transportation system seems to be inescapable, as a result of the increasing urbanization and challenges regarding global sustainability. The concept of Mobility-as-a-Service (MaaS) is regarded by policy-makers as an answer to the needed change. Generally speaking, MaaS is an online platform that enables users to plan, book and pay a trip out of a variety of transport modes, conventional and shared. However, in the literature, the potential impact of MaaS on mobility is still relatively unclear. This study, therefore, aims to provide insights into which factors influence the intention to use MaaS among private vehicle owners, who have until now been identified as relatively MaaS-averse travellers. Policy-makers are highly interested in this group to start using MaaS since their shift from private vehicles to other transport options might positively contribute to easing the congestion and environmental problems. In order to create some insights on possible travel behavioural shift and adoption of new systems, an empirical study has been conducted among (co–)owners of motorized vehicles (passenger car, electric passenger car, van, motorcycle; moped) that live in the Netherlands. The survey was based on a conceptual model that explains why people would use this new system (MaaS) and has asked respondents about their travel behaviour, socio-economic characteristics and attitudes towards MaaS. Using Latent Class Cluster Analysis (LCCA) five clusters in the sample population regarding the intention to use MaaS were identified. The cluster profiles show that private vehicle owners who often use public transport and active modes are most inclined to use MaaS, whereas the ‘conservative’ passenger car owners who use the car as their main mode of transport for all their trips (e.g. commuting, leisure) show a lower intention to use MaaS. As it can be expected that the societal benefits of MaaS will especially occur when these conservative car owners adopt MaaS, we conclude that, from a policy perspective, implementing MaaS could be less effective in reducing transport externalities (e.g. pollution and wasted time in congestion) as perhaps expected.

Neighbourhood mobility hubs may play an important role in mitigating the impact of passenger cars on climate change and urban public space. As a relatively new concept, academic research on the user potential of neighbourhood mobility hubs is so far limited. This research aims to identify which user groups are likely to adopt services offered by a neighbourhood mobility hub. A survey was distributed in the Netherlands (N=298), an Exploratory Factor Analysis (EFA) executed and a Latent Class Cluster Analysis (LCCA) estimated. Four distinctive groups of intended users are uncovered. Two of the clusters have intentions to use neighbourhood mobility hubs. Two other clusters do not (yet) intend to use neighbourhood mobility hubs. The clusters indicate that people who currently already travel more by sustainable modes (train or (e-)bicycle) are more likely to be adopters of neighbourhood mobility hubs than the traditional car users. In practice, this may limit the positive effect of hubs or even increase car use. However it could also facilitate those travelling sustainably to do so for longer as additional shared modes become available to them via hubs. Limitations and directions for further research are discussed.

As a solution to the high greenhouse gas emissions and declining quality of life caused by private vehicles, the shared mobility hub is introduced. The shared mobility hub is a place where multiple modalities come together, including public transport and shared private mobility. As the shared mobility hub is a relatively new solution, limited research is available on the topic, especially on finding potentially suitable locations for allocating them. In this research, this knowledge gap is addressed by developing and testing a generic methodology to determine suitable locations for a specific type: the regional shared mobility hub. The regional shared mobility hub is located outside a city center being able to act as an intermodal point of transfer. The developed methodology is a combination of two existing methods: the GIS Multi-Criteria Analysis (MCA) and Multi-Actor Multi-Criteria Analysis (MAMCA) available in the literature. The method is able to score and weight different criteria which determine regional shared mobility hub suitability, taking the end-user (traveler), operator, and government perspectives into account in the weighting. Results are presented in multiple heat maps based on scenarios with varying stakeholder weight importance. The methodology developed consists of five criteria that measure location suitability (potential demand at a certain location, hub implementation costs, generalized travel costs from and to the hub, link to surroundings, and societal impact) measured by nine attributes. In this method, the choice is made for the Analytic Hierarchy Process (AHP) to determine the criteria weights. The developed methodology is applied to the region of Rotterdam (The Netherlands) to analyse if the methodology produces useful results for policy implementation. From multiple analyses, it appears that the methodology is suitable for tackling the location suitability determination problem, as it produces intuitive results.

In this study a unique bicycle sharing program (BSP) is studied: a BSP initiated by an urban transit provider (buses and trams). The idea is that the combined use of BSPs and buses and trams could increase the catchment area of urban transit alone, therefore offering a more competitive alternative for the car. However, in the scientific literature hardly any knowledge is available regarding to what extent, by whom and how this bicycle – urban transit combination is used. This study explores the so-called ‘HTM-fiets’ programme in The Hague, the Netherlands, operated by urban transit operator HTM. Within the case, data was collected through a survey among the users of this program. The results indicate that, in this case, only 9% of the respondents use HTM-fiets in combination with urban transit. Of bike users who use HTM-fiets as a stand-alone mobility option (i.e. without combining it with transit), 46% have used the HTM-bike as substitute for bus and tram. Our results imply that the transit provider of ‘HTM-fiets’ faces difficult policy choices. The large degree of substitution may negatively influence their business case. However, a large degree of substitution is at the same time not a problem per se for them, because this substitution may alleviate crowding problems in transit and ‘HTM-fiets’ can be seen as an extra service by them offered to people in the Hague to ensure better accessibility of the city. The main lesson would be to focus on an integrated design of BSP and public transport in case a complementary system is aimed for, since our case shows clearly that without an integrated design especially substitution will take place from urban transit to the bicycle.

Tradable credits for congestion management are a novel policy concept that is receiving increased interest in transportation research. This interest is mainly driven by the belief that the concept can count on stronger social support and hence has a better prospect for implementation than charging-based instruments. This paper is the first to provide an analysis of the social, political, economic and technical feasibility of this concept. To this end, policymakers and researchers from the field of transport have been interviewed. The results reveal so many barriers and challenges in the social and political context that some seem insurmountable, which exposes a difference with expectations formulated in the literature. We reflect on possible options to overcome or avoid barriers but conclude that the concept of tradable peak credits lies very far from the current way of thinking about road use and seems unable to compete with more established charging schemes.