Publications

This study argues that policymaking guided by public values can help to secure public benefit in technology implementation, for two reasons. Firstly, the emergence and deliberation over plural values can result in more publicly beneficial outcomes; secondly, public values establish the meaningful link between public interest and policy goals. We explore the value bases of arguments around the societal implementation of autonomous vehicles through interviews with professionals. Mapping values on a conceptual model with two dimensions of recognition-neglect and consensus-dissensus, we find that a limited set of values receives recognition, while two distinct sets are contested or neglected almost entirely.

The assessment of transport systems has traditionally focused on congestion and ridership as its core performance measures. These perspectives fail to account for the actual service people seek from the transport system—the ability to reach destinations. Recent studies have shifted to focus on accessibility as a performance indicator, but do not address the question whether the observed accessibility is sufficient for meeting people’s daily needs. This paper contributes to the accessibility literature by (1) applying a people-centered approach to the performance assessment of transit systems and (2) exploring the factors explaining the differences in performance between regions. The paper proposes the Accessibility Sufficiency Index (ASI) as a performance standard. The ASI is based on a sufficiency threshold representing an accessibility level that is assumed to enable adequate access to destinations. The paper uses neighborhood transit job accessibility data to calculate separate ASI scores for different sufficiency thresholds for 49 large US metropolitan areas. Regression analyses show that transit system performance is shaped most strongly by transit vehicle revenue miles, mixed land uses, and activity centering. Importantly, the size of these effects varies by the employed sufficiency threshold, suggesting that transportation and land use factors affect transit performance at different spatial scales. The results have implications for the ways we evaluate transport and transit systems and for our understanding of the factors that affect their performance.

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).

Recent transport equity literature has proposed a sufficientarian approach to transport planning, according to which all individuals would be entitled to a minimum level of accessibility deemed adequate or sufficient. The implementation of this approach would require the adoption of an accessibility standard as a key performance indicator guiding transport investments, land use planning and service provision. While accessibility measures are increasingly operationalised in professional practice, the adoption of actual accessibility standards is rare. In this paper, we explore the barriers for adopting explicit accessibility standards and identify conditions within which such standards could be acceptable to practitioners and policymakers. The paper draws on interviews with professionals in three city-regions in Sweden, where the process of setting (accessibility) standards is on the agenda, complemented with interviews with practitioners from the Flanders region in Belgium and from the UK, where there have been recent developments in the realm of accessibility standard-setting. We find that authorities are hesitant to define and measure accessibility and that where definitions and performance indicators exist, there is a lack of agreement within and across authorities. The prospect of introducing a standard across the board without attaching any conditions comprises a further reason for shying away from standard-setting. The (dis)integration of transport and land use and complicated administrative and governance structures are described as a further barrier, while demand responsive transport is in some cases considered a panacea to all accessibility problems, making it possible to avoid setting standards. Our findings suggest that standards for minimum accessibility could gain political support if their reach is clearly circumscribed, and their benefits are clearly understood.

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.

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.

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.

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.