Publications

The evaluation of how particular segments of society fare is a common concern in many policy and academic realms, including transportation. The Target group Position Index (TPI) is introduced to assess the relative situation of a target group compared to a larger population. It uses two distinct population-specific benchmarks to determine the relative position of the subgroup: a theoretical worst-case and a theoretical best-case situation. An application of the index to transport is also presented, using 49 of the largest US metropolitan regions as case studies. Job accessibility by public transport is assessed for two population subgroups especially likely to benefit from public transport: adults without a car and adults living in poverty. It is found that the car-less population is comparatively better served by public transport than the poor population. Additionally, regions with a higher TPI score for car-less populations also tend to have public transport systems that better serve their population living in poverty. These results highlight that the proposed index allows for easy comparison across regions, despite large differences in the scale of the variable of interest (accessibility by public transport), the total population, and the size of the target groups (car-less or adults in poverty).

Travel demand modeling has been used as a tool by transportation professionals for defining travel behavior processes and procedures for close to seventy years. With origins tied to the construction of the interstate highway system, our pursuit to understand the connections between human behavior and infrastructure is an under-examined part of transportation planning's history. Many of the underlying assumptions in modeling practice influence transportation legislation, development review procedures, impact fee schedules, parking regulations, and environmental impact statements, to name a few. However, as transportation investments are expected to address new goals such as economic development, environmental justice, improving public health, or mitigating/adapting to climate change, the travel demand modeling practice needs to evolve. Our focus on travel demand as a technical exercise carries implicit assumptions and values that should be scrutinized if we wish to avoid reinforcing the perceived disparities of the past. With new challenges, we need new questions centered around who benefits from investments, the role of transport in increasing access to opportunity, transport costs and location affordability, and how the systems and processes of planning can change to meet more multifaceted goals.

Through the lens of the Social Identify Theory (Tajfel, 1974), this research aims to understand how social identity affects the perception of cycling as a mode of transport among women from different socio-income backgrounds. Using the case study of Tel-Aviv-Jaffa (Israel), we found that cycling is associated with distinct social categories rather than seen as a 'socially neutral' practice. In particular, we found cycling to be associated with 'being a Tel-Avivian' and with a healthy and active lifestyle. Such distinct identification of cycling is likely to enhance cycling uptake among more privileged groups, who are often able to identify with these social categories. In contrast, it may create a barrier for underprivileged groups, who do not identify with these social categories. In addition, we show how e-bikes – which are not identified with privileged groups – do not provide an identifiable alternative for women from all groups, as it is identified with “tough” and “violent” men. Furthermore, we show how cycling, in general, is perceived as “tough”, “dangerous” and as requiring a “constant struggle” over space with other road users, and hence fits a typical “masculine” behavior. Finally, we show how currently cycling is perceived by the underprivileged as a threat to their way of life or even as a symbol of them being pushed out of their neighborhood – a perception that limits cycling uptake among these social groups. These findings underscore the importance of accounting for social identity in cycling research and policymaking, especially in low-cycling contexts.

Many studies on transport equity have analyzed disparities in access to destinations between different population groups. In this study, we challenge this disparity approach and propose an alternative: analyzing accessibility insufficiencies. We argue that disparity analyses fall short on two accounts. First, they are based on group averages that inherently hide in-group variation. Second, they compare accessibility levels between groups without addressing whether these levels actually allow people to engage in daily activities. The proposed sufficiency approach avoids the former and addresses the latter by setting an explicit sufficiency threshold for accessibility. Empirical analyses for 49 of the 50 largest U.S. metropolitan areas confirmed the problematic nature of disparity analyses. In line with most literature, our disparity analyses show that disadvantaged groups are virtually always better served by transit than their more advantaged counterparts. Yet a systematic sufficiency analysis reveals large inequities in accessibility, regardless of the exact sufficiency threshold employed.

Our outcomes underscore the need for researchers and planning practitioners to move away from seemingly neutral disparity analyses toward equity analyses of insufficiencies. Though this move implies inevitably normative, and thus politically difficult, decisions, such analyses enable professionals to systematically identify transport inequities as input for regional transport plans. They may also be used to prioritize already proposed interventions based on their contribution to a reduction in accessibility insufficiencies.

Using the Ethical Delphi method, this research seeks to understand how professionals relate to ethical socio-spatial implications of possible widespread autonomous vehicle (AV) deployment in cities and societies, and to distil values that can shape AV futures. First, we sought to understand whether professionals engage in ethical thinking and reasoning regarding AV implementation, and the ethical considerations and values they use. We found that professionals give a range of arguments and rationales stemming from different value dimensions. Responses show evidence of engagement in ethical thinking, the use of ethical arguments, and an appeal to ethical values. Secondly, we mapped the value dimensions pertinent to AV implementation and ranked them to reflect their importance as perceived by respondents. Thirdly, we categorise the value dimensions into four groups: dominant, important but neglected, less prioritised, and less elucidated value dimensions, through which possible gaps in the conceptualisation of societal implications of AV implementation are brought to the fore. Finally, this study contributes our experience of applying the Ethical Delphi as a method for the ethical evaluation of novel (urban) technologies.

The use of Informal Public Transport (IPT; i.e., minibuses, motorcycles, and tricycles) for activity participation in Dar es Salaam is associated with mobility difficulties, e.g., traffic congestion, unscheduled services, and lack of safety of the journey. The introduction of the Bus Rapid Transit (BRT) in May 2016 aimed at reducing mobility difficulties by improving public transport (PT) with scheduled services and fully dedicated lanes to improve access to the Central Business District. This study compares individuals' travel behaviour before and (2 years) after BRT implementation using a GPS-app to explore changes in spatial mobility demands, i.e., (new) visited places, frequency of travel, trip distances, and departure times. Short surveys were used to record the socio-demographic characteristics. Results: the use of IPT remained a necessary means of transport for low-income individuals to commute outside the BRT corridor in multiple destinations, as the use of the BRT route is spatially limited. The new BRT system had become the main option for trips conducted to fixed destinations along the corridor and within service hours. The spatial mobility patterns showed that individuals are now adding BRT to their trip chaining, enabling them to access amenities, make more trips and travel farther distances. The results provide insights for transportation planners who tend to focus mainly on BRT as the only solution for all mobility demands. Each transport system has its own spatial mobility benefits to offer. An integrated PT within a framework of a multimode system is vital for inclusive mobility.

Recent transport equity literature suggests that accessibility analyses should move beyond mapping of the uneven patterns of access to opportunities. Instead, this literature proposes a sufficientarian approach, according to which all individuals are entitled to a minimum level of accessibility. In line with this approach, in this paper we ask: “What are the spatial patterns of accessibility insufficiency in U.S. metropolitan areas?” We use the Accessibility Fairness Index developed by Martens (Martens, K., 2017. Transport justice: Designing fair transportation systems. Routledge) and others to measure accessibility insufficiency. This index accounts for both people's accessibility shortfall compared to a sufficiency threshold and the number of people affected by these shortfalls. We limit our analysis to 49 of the 50 largest U.S. metropolitan areas and to people particularly reliant on transit, as they are especially likely to experience insufficient accessibility. We analyze first the spatial patterns of accessibility insufficiency for all 49 metropolitan areas jointly, for sufficiency thresholds ranging from 1% to 50% of average regional car-based accessibility. We find that accessibility insufficiency among people relying on transit is strongly concentrated in the first 10–30 km ring around the metropolitan core, with a more dispersed pattern only prevalent for the lowest 1% threshold. Next, we compare the 49 regions using only the 10% sufficiency threshold. Results show that most regions have a strong concentration of accessibility insufficiency in the urban cores and inner suburban ring. Urban densities in these clusters are relatively high, underscoring the favorable conditions for introducing efficient transit service. We conclude that accessibility insufficiency is not merely an issue of far-flung exurbs and the metropolitan fringes, but just as much a problem affecting the large transit reliant population in the urban cores and inner suburban rings. This underscores the possibilities for addressing the issue through increased and targeted investments in high-quality transit systems and transit-corridor urban densification.

The US Department of Transportation requires metropolitan planning organizations (MPOs) to consider social equity in their plans and projects in accordance with civil rights–related laws. In this paper, we suggest four interpretations of directives’ distributional standards in relation to accessibility. Employing this framework, we review the equity assessments of regional plans of the ten largest MPOs in the United States. Against our expectations, we find that MPOs tend to employ relatively strong distributional standards, albeit never explicitly. We argue that more explicit guidance regarding standards would improve the fairness and consistency of planning practice.

The use of Informal Public Transport (IPT) in Dar es Salaam, Tanzania, has been associated with mobility difficulties, i.e. traffic congestion, unscheduled service and lack of safety and security. The introduction of the Bus Rapid Transit (BRT) system was therefore considered as a powerful intervention for these mobility difficulties. In May 2016, the BRT started operating with exclusive bus lanes and a clear schedule to offer a qualitative, accessible and affordable system. This paper explores changes in travel experiences and perceptions of individuals (local inhabitants) regarding IPT and BRT use in meeting mobility demands before and after implementation of the BRT. Focus group discussions and short questionnaires were conducted before and after BRT to explore changes in mobility experiences among different individuals. Results show that in both periods, the demand for IPT use remained dominant, driven by a low fare, connectivity within a neighbourhood and outside the major road, flexibility and the possibility to commute with goods. The use of BRT was mainly attributed by relief in traffic congestion (when only considering in-bus time) and a lack of options along the corridor. Surprisingly, BRT users also experienced several mobility difficulties after implementation: long waiting time, overcrowding (in-bus and stations), and difficulties to commute with goods, and a lack of safety and security. Peri-urban individuals continued to experience more travel difficulties with both transport systems than individuals in areas adjacent to the BRT because of limited connectivity, congestion and unpaved local roads. For low-income individuals, the BRT was considered as another burden for their livelihoods (higher financial cost) rather than it was expected as a solution towards a high quality, accessible and affordable system. There is a need to integrate public transport with supportive improved local roads to serve multiple destinations.

The Capability Approach, developed by Sen and Nussbaum, has recently gained increasing attention in the transport literature. This paper adds to this growing body of literature by investigating how the approach can generate consistent evaluative approaches to inform (urban) transport planning. The paper reviews the mobility literature that has investigated the Capabilities Approach and identifies the opportunities and challenges of employing the approach as a basis for transport planning. The review highlights the different, and sometimes patchy, ways in which the key notions of the approach have been conceptualised and operationalised. Discussing this growing but scattered literature, the paper embraces the emerging direction that understands accessibility as the capability that transport planning and policy should consider. Further refining this understanding, the paper proposes a twofold evaluative approach combining a top-down and a bottom-up component to capture the myriad of conversion factors shaping people’s accessibility-as-capability and functioning. By systematically adopting the Capabilities Approach, transport planning and mobility policies will be directed to enhancing each person’s freedom to pursue the life they have reason to value in contemporary societies.