This study explores perceived accessibility specific to air transportation in the Dutch context through a focus group study. Five focus group sessions were held with a total of 24 participants with air travel experience within the past five years. Online focus groups were held during the period that the COVID-19 pandemic travel restrictions were in effect, specifically around 12 months after the travel restrictions were implemented globally. In terms of the importance of activities accessible by flight, we observe that travelers particularly attach importance to visiting family and relatives, while the importance attached to the business and recreational activities accessible by flight varies among participants. As far as the transport component of accessibility is concerned, we find that, in addition to conventional variables in air transportation research, such as cost and travel times, unconventional variables such as uncertainty during flight schedule disruptions or the mood of staff and other passengers contribute to perceived accessibility by air transportation. Based on the results, we further discuss characteristics specific to perceived accessibility by air transportation, directions for further qualitative and quantitative research regarding perceived accessibility by air transportation, and implications for policy and planning.

@en

The aim of this conceptual paper is to contribute to a better understanding of the front-end phase of large public projects, which is complex and non-linear. The point of departure relates to a number of paradoxes found along the way of the front-end. A processual approach is taken to follow the front-end over time. Considering a number of example vignettes, four paradoxes and subsequent trade-offs are discussed which affect the strategic decisions that need to be made. These are found to fit largely within four generic sub-processes identified in the front-end. Inspired from the paradox theory, we conceptualise paradoxes and trade-offs under the dynamic equilibrium model adapted for temporary organising such as large public projects. Main aim of this paper is to consider how decision-making can be improved, and managerial strategies developed that permit the acceptance of paradoxes and their resolution in a virtuous cycle leading to long term success.@en

Van februari 2003 tot januari 2025 werkte ik aan de TU Delft als hoogleraar Transportbeleid. Wat zijn belangrijke trends in ontwikkelingen, in onderzoek en beleid? Dit artikel geeft een beknopt en selectief overzicht van enkele dominante onderwerpen, met het accent op personenvervoer.@en

As cities grow, the benefits of living in them are increasingly unequally distributed. USA cities, in particular, have experienced rapid suburbanization of poverty and decreased levels of access to jobs for transit-dependent and vulnerable communities. The public transit challenges in suburbs call for innovative forms of transit to turn the tide on urban inequality. On-demand microtransit, a novel type of shared mobility provides efficient, convenient and affordable transportation. Its potential for redressing inequity had yet to be investigated fully in a suburban setting. We presented a case study from the suburbs of Minneapolis-St. Paul in Minnesota, USA. We combined unique datasets of microtransit ridership from two public transit agencies, transit surveys, land use data, and expert interviews, to conduct spatial analysis, accessibility analysis, and equity impact assessments for these suburbs. We found that microtransit enables public transit agencies to reach a larger number of vulnerable riders than fixed-route transit, particularly for commuting and trips to/from commercial areas. Microtransit also provided a cheaper alternative to ride-hailing and a faster alternative to public transit and walking, without cannibalizing ridership from fixed-rout transit alternatives. Finally, microtransit redressed transportation inequities by alleviating access inequality, reaching vulnerable rider groups effectively, and creating travel opportunities that are less spatially concentrated than those provided by traditional, fixed-route public transit. This study provided a framework for further investigations into the impact of microtransit, including in urban core or rural settings, and highlighted the impact of microtransit in reducing access inequity in a suburban environment.

@en

Car sharing contributes to reducing emissions, resource depletion, and land take, by promoting more efficient use of vehicles that on average sit idle 96% of the time. But consumer adoption remains limited. User segmentation studies can inform efforts to mobilize potential users to join car sharing, and to anticipate what their needs and usage characteristics will be. This paper proposes a comprehensive segmentation method based on socio-demographic variables, which reveals differences in preferences for car sharing platform type, usage characteristics and societal outcomes of car sharing use. To do so, we apply a three step Latent Cluster Analysis to a nationwide sample of active car sharing users. This method results in a set of user segments that reflect distinct life phases, with different needs in terms of the frequency and type of trips made by car sharing. This is reflected in different preferences for car sharing platform types, as the likelihood to use peer-to-peer car sharing as opposed to business-to-consumer car sharing differs by user segment. The segments do not differ substantially in their motivations for engaging with car sharing. Yet, environmental motivations for car sharing outrank financial motivations, while social motivations play no substantial role. The clusters do show substantial differences in the changes in car ownership that occur while being an active car sharing member as well as the likelihood to use car sharing in place of a private car rather than public transport or walking and biking. We conclude that a comprehensive segmentation method based on socio-demographic variables provides actionable insights for upscaling car sharing adoption, as well as targeting specific user segments in order to optimize societal outcomes from car sharing use.@en

Car dependence brings along many negative social and environmental externalities that policymakers and stakeholders need to consider. Nonetheless, the concept is not well defined and lacks a clear framework regarding its determinants and mechanisms, which also leads to problems in terms of its operationalisation. Therefore, this paper proposes a conceptualisation and operationalisation of car dependence, which can serve as a basis for further research and policy. We define car dependence as the extent to which an individual is incapable to participate in location-based activities without a car in a satisfactory way. This definition is based on the theoretical background of the capabilities approach and the concept of motility and also linked to the concept of accessibility. Our conceptual model consists of seven components, most of which have been considered separately in previous conceptualisations, namely the land use system, transport system, natural environment, temporal component, social environment, and individual objective/subjective characteristics. These components range from being external to the individual (e.g. the land use system) to internal (e.g. individual features). Considering these components jointly emphasises the importance of looking at car dependence in a holistic, unifying way. This approach contributes to a better understanding of car dependence that goes beyond the explicit analysis of components in previous research. In addition, we provide a systematic approach to operationalising car dependence that contributes to a more comparable approach to measuring car dependence. Researchers have to decide whether they want to examine car dependence via its components or via self-report by individuals, whether they want to study the full set of components or only a subset, and whether they want to consider perceptions or factual information about external components. Therefore, our conceptualisation and operationalisation provide valuable new insights into car dependence regarding new research directions and policy approaches.

@en

This study aims to evaluate equity in cycling initiatives and their operational challenges by reviewing a wide range of cycling initiatives implemented in Auckland, New Zealand. The effectiveness of current initiatives with respect to various target groups or resulting beneficiaries is discussed, along with potential additional initiatives, barriers to implementing cycling equity initiatives in practice, and possible solutions to address such barriers. By interviewing policymakers, decision-makers, planners, designers, and transportation professionals, 44 cycling initiatives are identified. Results suggest that the geographical distribution of some of the current initiatives implemented could be more equitable. While some initiatives are equitable, there remain challenges with respect to their implementation. Additionally, there are limited initiatives focusing on the safety of female cyclists in Auckland, and no initiatives specifically aimed at Māori and Pacific people, groups that can both be considered disadvantaged with respect to cycling in Auckland. Potential additional policy initiatives include e-bike/bicycle subsidies, policy and law changes, education and awareness campaigns, better urban planning, policies aimed at making cycling easier, and better monitoring and evaluation. Barriers to the implementation of cycling equity initiatives in practice include sociocultural issues, financial constraints, poor planning, human resource limitations, and the built environment. Suggested strategies to help overcome some of these issues include adopting an equity lens and providing equity assessments for all initiatives, thus providing a wider coverage with respect to diversity in the population, enhanced engagement with the community, and the empowerment of people.

@en

Smooth cycling can improve the competitiveness of bicycles. Understanding cycling speed variation during a trip reveals the infrastructure or situations which promote or prevent smooth cycling. However, research on this topic is still limited. This study analyses speed variation based on data collected in the Netherlands, using GPS-based devices, continuously recording geographical positions and thus the variation in speeds during trips. Linking GPS data to spatial data sources adds features that vary during the trip. Multilevel mixed-effects models were estimated to test the influence of factors at cyclist, trip and tracking point levels. Results show that individuals who prefer a high speed have a higher average personal speed. Longer trips and trips made by conventional electric bicycles and sport bicycles have a higher average trip speed. Tracking point level variables explain intra-trip cycling speed variations. Light-medium precipitation and tailwind increase cycling speed, while both uphill and downhill cycling is relatively slow. Cycling in natural and industrial areas is relatively fast. Intersections, turns and their adjacent roads decrease cycling speed. The higher the speed, the stronger the influence of infrastructure on speed. Separate bicycle infrastructure, such as bike tracks, streets and lanes, increase speed. These findings are useful in the areas of cycling safety, mode choice models and bicycle accessibility analysis. Furthermore, these findings provide additional evidence for smooth cycling infrastructure construction.

@en

Air transportation is a mode of transport developed specifically to provide access to long-distance destinations that may otherwise be infeasible or at least more difficult to reach. Accordingly, there are distinct aspects of air travel that require consideration when assessing accessibility by air transportation, which are not addressed in general local accessibility studies. This paper reviews studies of accessibility by air transportation. The studies in question were published in academic journals, and we analysed them using the broad theoretical framework of accessibility of Geurs and van Wee [Accessibility evaluation of land-use and transport strategies: Review and research directions. Journal of Transport Geography, 12(2), 127–140]. We discuss the characteristics of accessibility by air transportation to consider when designing research, as well as trends and knowledge gaps in the existing literature. An important gap is that, while there is a growing interest towards perceived accessibility by air transportation, accessibility measures based on this perspective have not yet been applied yet. Additionally, the literature is largely focused on the transport and land-use components of accessibility as opposed to the individual and temporal components. We finish by discussing the benefits and drawbacks of directly applying conventional accessibility measures for research on accessibility by air transportation, as well as options to modify the temporal component of conventional person-based accessibility measures for better applicability in the air travel context.

@en

Latent Class Analysis was used on the 2018/19 Dutch National Travel dataset to assess travel behaviour profiles and its connection with sociodemographic and spatial factors to grasp travel patterns in a more holistic context than previous research@en

This Special Issue has its basis in the BIVEC-GIBET Transport Research Days 2021. The three papers reflect the broad scope of the BIVEC-GIBET, including several disciplines, all transport modes, and many research methods. What the research of BIVEC-GIBET has in common, is a focus on societally and policy relevant research.@en

This study explores the effectiveness of cycling initiatives in encouraging bicycle usage, and the relationship with sociodemographic characteristics amongst residents of the multi-cultural city of Auckland, New Zealand. The study considered regular cyclists, potential cyclists, as well as non-cyclists across demographic groups, including age, gender, income level, educational level, ethnicity, and bicycle user type to provide a holistic understanding of the association between the perceived effectiveness of cycling initiatives in encouraging bicycle usage. The results indicate that safety initiatives, including lighting improvements and vehicle safety features are perceived as being the most effective amongst all of the cycling initiatives proposed, and that younger people, Māori and Pacific people, and regular cyclists perceive higher levels of effectiveness in response to many of the cycling initiatives implemented. Moreover, findings indicate that many of the cycling initiatives are seen as more effective by some specific demographic groups who were not necessarily the intended target groups for the initiative, as envisaged by the experts tasked with their development and implementation. Also, for some demographic groups such as the elderly, women and non-cyclists, the perceived effectiveness of current cycling initiatives was found to be lower than was the case for the population as a whole, suggesting that the current cycling initiatives are not sufficiently focussed on these cycling disadvantaged groups, as they should to be in the interest of equity. This study aids in the design of better strategies by providing insights for policymakers and local governments to provide more equitable outcomes with respect to cycling.@en

Innovations in transportation can contribute to reaching relevant societal objectives (e.g. reduce emissions, congestion levels and/or risks). To determine which innovations to stimulate (and which not) it is important for policy makers to assess their effects on beforehand. Expert judgement is an often-used method for this purpose. Although expert opinions can provide useful input for decision-making, these judgement are potentially subject to change, for example, due to new information becoming available or because the (academic) discussion about the innovation in question takes a new turn. Studies that explicitly study stability and change in expert judgements are rare, but highly relevant to determine the reliability of experts' assessments. To address this gap, this study assesses experts’ judgments at multiple points in time focusing on the effects of a transport innovation with potentially widespread societal implications, namely Automated Vehicles (AVs). To this end a survey was administrated to a group of experts involved in the WISE-ACT project. The results indicate that expert opinions towards this innovation are generally favorable; AVs are believed to reduce congestion delays, greenhouse gas emissions and traffic accidents. Although the consulted experts are generally quite stable in their opinions, they are becoming less optimistic about these positive effects over time. A Q-factor analysis additionally reveals two clusters of experts, one with a positive and one a negative outlook on AVs. The latter group beliefs that AVs will lower the value of travel time, thereby increasing travel demand, and, in turn, emission and congestion levels. Overall, the changing and diverging opinions among experts indicate that the transition to AVs is not necessarily regarded as a desirable one.@en

Ensuring equity is considered in all types of decision making, including with respect to cycling provision, is important. Studies have investigated equity in relation to provision of cycling infrastructure and facilities. However, identifying other factors that need consideration in cycling equity is important. This study explored the impact of cycling infrastructure provision on individual perceptions of cycling infrastructure in relation to sociodemographic characteristics in Auckland, New Zealand. The results indicated that bicycle lane availability did not significantly influence perceptions of cycling infrastructure; however, ethnicity and whether a person was a regular cyclist did. Among noncyclists and potential cyclists, ethnicity was the only factor found to significantly influence perceptions of cycling infrastructure. Maori, the indigenous people of New Zealand, and Pacific Islanders rated the provision of cycling infrastructure higher than others for the same level of bicycle infrastructure in their community. Whereas Maori had the highest percentage of potential cyclists among all ethnicities, Pacific Islanders had the highest percentage of noncyclists (64.9%), the lowest percentage of potential cyclists, and one of the lowest percentages of regular cyclists. The study showed that cycling provision perceptions were more affected by factors like ethnicity, education, and bicycle user type than objective measures of bicycle infrastructure. Following the capabilities approach of justice, this study suggests that equitable provision of cycling infrastructure may not lead to an equitable cycling environment. To achieve this, interpersonal and intrapersonal indicators such as ethnicity and community-related factors must also be considered to encourage and empower all population groups to cycle.@en

This chapter gives an overview of dominant analytical approaches in the field of transport and land use and how they relate to empirical research on modeling important theoretical concepts, such as induced demand and constant travel time budgets. Further, it explains the mutual relationships between these concepts and makes connections between these concepts and policy issues. Finally, this chapter addresses gaps in knowledge, and suggests related avenues for future research, policymaking, and planning.@en

In the coming years, cities will have to deal with transportation challenges in terms of accessibility and sustainability. Passenger and freight transport are expected to increase, while the transport sector is a major contributor to greenhouse gas emissions and congestion in cities. Although historically both ecosystems (passenger transport and freight transport) were intertwined, the ecosystems have developed separately from each other over the past century. This research focuses on finding integrated logistics flows and logistics innovations and especially finding the conditions under which these can be added to different types of mobility hubs. By collecting and structuring information from literature and interviews using a requirement analysis, possible logistics additions and associated conditions are mapped into frameworks. The results show that small consumer goods flows have the highest potential to be added to mobility hubs. In addition, the frameworks show that they can be used as a first step in the analysis to investigate which logistics functions and under which conditions these could have potential on a mobility hub. Further research can, preferably quantitatively, examine whether the suggested logistics additions from the framework are applicable in more detailed areas. @en

This paper explores to what extent inequalities in travel times, measured via the Gini index, depend on the spatial scale at which (average) travel times are measured. By using the new concept of Dedicated Accessibility Points, for the Netherlands we calculated average travel times at four spatial levels, ranging from virtually individual addresses to the level of municipalities. Travel times by car and bicycle to three medical points of interest are calculated: pharmacies, family doctors, and hospitals, as well as travel times by car from three other points of interest: ambulance stations, fire stations and police stations. At the level of individual addresses the errors made due to spatial aggregation is absent, but at higher spatial scales it plays a role. The results show that the Gini index is heavily influenced by the spatial scale at which the indices are calculated, with smaller indices at higher spatial scales. We discuss the implications of these differences for research and policy.@en

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.

@en

This extensively updated textbook introduces the transport system and its societal impacts in a holistic and multidisciplinary way. A timely second edition, it includes new analyses of travel behaviour and the transport system’s impacts on health and well-being.@en