Publications

Most applied research on transport justice focuses on evaluating existing systems, while transport planning typically relies on utilitarian objectives such as minimizing average travel time, without accounting for fairness. This paper starts to bridge this gap by applying different principles of justice to the operational planning of transport systems. We use an intermodal Autonomous Mobility-on-Demand system—centrally controlled self-driving vehicles cooperating with public transit and active modes—as a case study to improve conditions for users without access to private cars. We define and compare justice metrics that differ in both their distributive principle and the good of concern: utilitarianism applied to travel time, and sufficientarianism applied to either travel time or accessibility. A real-world case study in Eindhoven, the Netherlands, shows that these principles lead to different planning outcomes, highlighting the need for a broader debate on their implications. The results underscore the value of transdisciplinary and conceptually informed approaches to transport planning and system optimization.

Paratransit, often the sole public transport option in many cities in the Global South, typically suffers from low service levels, pollution, safety concerns, crashes, and a lack of respect for users. This study leverages the concept of dignity, which is not yet systematically explored in transport literature, to examine the experiences of paratransit actors. Dignity has been effective in other fields to expose unjust relationships and propose enhancements, which have inspired its exploration in transport research in this paper. Employing ethnographic methods like observation ride-alongs and post-ride interviews, the study captures detailed paratransit experiences of users, drivers, and conductors in Nairobi, Kenya. Thematic analysis identified experiences impacting dignity positively through acknowledgement, recognition, autonomy, and advocacy and negatively through diminishment, labelling, and minimising. Findings indicate that actor interactions can raise or lower dignity, with perceptions of dignity varying by actor demographic. Dignity violations experienced by crews affect how they treat users, suggesting the existence of an ‘ecosystem of dignity’, providing directions to positively affect dignity through policy interventions.

In recent years, the concept of proximity has garnered increasing attention in both transportation research and practice, albeit under various terms and interpretations. Among these, the concept of the 15-minute city has catalysed attention in planning practice, with recent evolution to the x-minute city and city of proximities. In research, proximity-centred accessibility has been offered as an umbrella term to express the ability to reach activities and destinations at short distances. Regardless of the terminology used, the essence of proximity lies in the ease with which one can access desired activities and destinations within reasonable travel times, independent of speed-enhancing transport modes most notably through walking.

This research investigates the nuanced meanings ascribed to proximity-centred accessibility by planning practitioners globally, spanning diverse regional and local contexts. For this, we used an online survey, disseminated among over 9000 practitioners from 22 countries across 5 continents, which generated over 1300 responses. The survey explored the preferred terms for proximity-centred accessibility and their definitions, specifically emphasizing time and distance thresholds and the identification of relevant activities. By juxtaposing our findings with an earlier survey of accessibility researchers, this study also contributes to the groundwork for a conceptual framework for proximity-centred accessibility.

Our findings affirm a relatively consistent interpretation of proximity among global planning practitioners, predominantly extending up to 1600 m, in accordance with earlier results for accessibility researchers. Despite some relevant dissimilarities among practitioners from megacities compared to their smaller city counterparts, or in specific countries (most notably the Netherlands), the distance that is considered proximate is the attribute that generates the most consistent results across different contexts. Also consistent was the relevance of short distances (up to 15 min walking) for activities such as primary and pre-primary schools, playgrounds, parks, food shopping, and pharmacies, reinforcing the importance of proximity to basic and caregiving activities. No term was found to be consistently meaningful across different contexts, although terms like local and neighbourhood accessibility and walking/pedestrian, or cycling accessibility, show higher preference in the global sample.

Road designs in Sub-Saharan Africa (SSA) prioritize motorized traffic, despite the high proportion of pedestrians. This study examines the extent to which different road designs hinder or enable walking in Kigali, Rwanda, employing an exploratory and qualitative research approach. To carry out the study, two arterial roads were selected: one with a basic design and one with a design in line with current standards in Kigali. The road designs were audited using a checklist, and interviews were conducted with 30 residents living near the roads. While both roads have basic walking facilities (sidewalks, crosswalks, and streetlights), the upgraded road has more facilities including a planted strip that separate the carriageway from the sidewalk, a small planted median, traffic lights, speed cameras, and police surveillance. These elements were appreciated by residents as walking enablers. However, they also highlighted long crosswalk intervals and lack of speed-calming facilities at crosswalks, resulting in regular crossing at unregulated points and feelings of unsafety while crossing the road. In addition, lack of sidewalk amenities on both roads were identified as barriers to walking. While highlighting the car bias in road designs leading to walking barriers in Kigali, we recommend more research on this topic in other African cities, which have been described as “unwalkable” and a shift toward more inclusive road designs that not only facilitate movement for all population segments, but also serve as spaces for community life and local entrepreneurs.

This study engages a sufficientarian perspective to examine the role current basic levels of public transport provision play in delivering sufficient accessibility for inhabitants of sparsely populated areas. A survey was conducted among people living in areas which meet the criteria set out for basic levels of public transport provision for the Västra Götaland Region, Sweden. Mixed methods were employed in the collection and analysis of the survey data. The links between socio-economic, socio-demographic, time constraints, and accessibility and transport-related characteristics on the one hand and suppressed travel combined with activity participation levels on the other were examined. Our findings indicate that the current provision levels play a limited role in delivering (sufficient) accessibility, with many reports of personal adaptive strategies and forgone trips. We found that young people were significantly more likely to report suppressed travel. We propose recommendations for the improvement of public transport-based accessibility in such contexts.

Mobility is a hallmark of functional ageing and a major health determinant in older adults. Mobility is known to decline with age, yet, except for research on driving cessation, little is known about the role of giving up other transport modes in this decline. This exploratory qualitative research focusses on public transport use, and aims to describe the process of ceasing to use public transport, its causes, and its effects on health and mobility.

This is a qualitative study, using semi-structured in-depth interviews. Participants were 23 older adults living in urbanized areas in Israel, aged 67-88 (mean 80.4 ± 6.5), in various stages of public transport use cessation. Interviews were recorded and transcribed verbatim, with transcripts thematically analysed inductively and deductively.

Public transport use cessation is described in terms of a semi-linear process beginning with slow mobility declines that lead to difficulties using particular public transport services. Coping mechanisms are sometimes used to maintain or regain public transport use, but eventually are not enough. Public transport use cessation then leads to a further decline in mobility and loss of independence.

Public transport use cessation is an important aspect of age-related mobility decline among older adults who use public transport. It has significant detrimental mobility outcomes, and in some cases leads to complete loss of independence, potentially accelerating age-related health decline. Future research should focus on quantitative analyses and investigate interventions to maintain independence further into the ageing process.

Prevailing methods of transport planning focus on the functioning of transport systems rather than on the services people receive from those systems. In line with this perspective, and as epitomized by the four-step model, road congestion has been seen as the main transport problem, and investments to ease congestion are given priority. This approach, still very dominant in the Global North, has de facto caused the gradual emergence of transport-related social exclusion, as it has ignored the mobility and accessibility difficulties by people with limited or no access to private motorised transport. Against this background, the research explores whether and how people-centred transport planning can be relevant to Sub-Saharan Africa, where a vast majority of the population currently has no or limited access to (private) motorised transport modes. This work proposes a new transport planning approach called transport justice. Transport justice focuses on providing transport interventions to sections of a community that are most deprived of the service. The work discusses a real case study of the cities of Blantyre, Malawi, and Kigali, Rwanda. The results show that households with access to private cars in Blantyre are almost ten times better of than households without cars in terms of potential opportunities within their reach. In Kigali, households with access to a car are almost thirteen times better of than households with no car in terms of potential opportunities within reach This approach to transport planning is significant as it encourages the quantification of the transport needs of people groups and the prioritisation of areas with the greatest needs in the implementation of transport interventions.

This paper presents an approach to use GPS-based travel behavior surveys to determine who is being served well and who is being served poorly by the transport system. We draw on the extensive literature on travel behavior, which has shown that people’s travel behavior is at least in part shaped by the travel barriers they experience. Starting from this basic insight, we define 17 parameters that may provide insight into a person’s relative ease of movement. These ease of movement parameters cover dimensions related to trip frequency and diversity (e.g., overall and in evening hours), transport mode use (e.g., as driver or passenger), travel speed (e.g., for public transport legs), distance (e.g., trip detour ratio), and effort (e.g., ratio between trip legs and out-of-home activities). No single parameter is sufficient to determine whether someone is served well or poorly by the transport system, as behaviors may be the result of choice as well as constraint. However, we argue that jointly the parameters are likely to differentiate well-served from poorly-served people. We apply our approach to data from six GPS-based travel behavior surveys conducted in Israel’s four main metropolitan areas (N = 62,981). We calculate z-scores for all ease of movement parameters, with negative values suggesting mobility problems and positive values relative ease of movement compared to the entire sample. We conduct four known-group analyses, comparing mean z-scores by level of access to a private motorized vehicle, age, gender, and disability. Results are systematically in line with expectations: population segments identified in the literature as experiencing (more severe levels of) transport disadvantage show systematically lower composite mobility scores. These outcomes are particularly striking, considering the short observation period of only one day per respondent. Taken together, these findings provide a first indication that revealed travel behavior patterns can be used to identify population segments poorly served by the transport system and thus to determine both success and failure of the existing transport system. While more research is needed, the approach also holds promise to determine the impacts of transport projects on people’s ease of movement.

Amidst rapid urbanization and increasing motorization, walking remains a widely used mode of transport in Sub-Saharan Africa (SSA). The frequency with which people walk, the distance for which they may be willing to walk, and the convenience and safety with which they can walk, depend significantly on road design. Moreover, the impact of roads on walking behavior will differ between population segments. Road designs in SSA typically prioritize motorized transport, neglecting pedestrians' safety and convenience, as well as aesthetic appeal of roads, and often ignoring the importance of roads and streets as a place for economic and social activities. This study addresses the under-researched relationship between road design and walking in a Sub-Saharan African city. We analyze residents' perceptions and experiences on two distinct roads in Bamenda, the third-largest city in Cameroon. Using a checklist, we assessed the selected roads for pedestrian-friendly and hostile elements. Thirty participants residing near the roads were interviewed to understand their walking experiences and perceptions of street walkability. Findings reveal poor walking conditions on both roads, which lack essential pedestrian infrastructure. Where present, pedestrian infrastructure is often obstructed by businesses and parked vehicles. Respondents reported walking to be (severely) affected by conflicts with motorized traffic and especially motorcycles, and poor road conditions resulting in dust and mud in dry and rainy seasons respectively. Surprisingly, poor road conditions may also enhance walking, as they reduce vehicle speeds and thus safety risks.

Background and aim Public transport use has been linked to several health benefits in the general population and is crucial for older adults’ mobility, due to an age-related decline in physical and cognitive capacity and mobility, particularly the ability to use other modes of transport. The objective of this systematic review is to determine what is known about the physical and mental health outcomes of public transport use of older adults and to identify remaining gaps in the literature. Methods Five electronic databases were searched in April 2023, and then updated in January 2024: Pubmed, Scopus, Web of Science, Ageline and Transport Research International Documentation (TRID). Included were studies that were in English, contained a measure of public transport use as exposure, and any health outcome, including mental or physical health, physical or cognitive function, morbidity, or mortality, among people aged ≥60 years. Results Of a total of 2247 unique records that were screened, the full text of 20 was assessed for eligibility and 11 were identified as eligible. Citation search identified two additional studies, amounting to a total of 13 included studies. Significant health outcomes described in assessed studies were decreased obesity and depressive symptoms, and to a lesser extent increased gait speed and cognitive function. Conclusions Initial evidence suggests a positive impact of public transport use on obesity, depressive symptoms, gait and cognitive function, although available research was limited in context and methodology. Further research should focus on determining causality between public transport use and health, and be conducted in more diverse contexts. Transport and urban planners, as well as policymakers, should consider the implications of public transport on the health and independence of older adults.