Browsing by Author "Wang, Jueyu"
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Item Beyond Accessibility and Behavioral Outcomes: Re-conceptualizing Equity in Transportation through the Capabilities Approach(2020-09) Wang, JueyuIn the past decades, transportation equity has attracted increasing attention from transportation researchers and policymakers. Nonetheless, there is a lack of theoretical understanding of transportation equity. The dissertation engages the Capability Approach of Sen and Nussbaum as a theory of justice and well-being to conceptualize transportation equity as the process of the production of the equality of mobility capabilities, the substantial freedom people have to travel. Specifically, I propose an equity evaluative framework of five evaluation domains, including 1) Access to basic resources, services, and activities sites; 2) The freedom of physical movement around places; 3) Opportunities for active travel (walking and bicycling); 4) Opportunities to conduct safe and psychologically satisfied trips; 5) Access to political engagement activities. The dissertation also applies the CA framework to two different empirical contexts. One assesses the inequalities of mobility outcomes and capabilities of traveling within low-car ownership households. The results reveal that low-car ownership people of different socio-economic groups achieve different mobility outcomes under the different levels of mobility capabilities. The analysis suggests the joint evaluation of mobility capability and outcomes in informing transportation inequity and disadvantage. The second examines the inequalities of travel mood among different socio-demographic groups and how mobility capabilities, measured as modal options and access destination opportunities, interact with travel mood. The results reveal the significant impacts of mobility capabilities on travel mood and the moderation effects of mobility capabilities on the relationship between mode and mood. The findings highlight the importance of explicit consideration of mobility capabilities– in policy debates and planning initiatives. The concluding chapter contextualizes these findings within the transportation literature and proposes several take-away for policy and future research directions.Item The effects of pedestrian and bicycle exposure on crash risk in Minneapolis(Journal of Transport and Land Use, 2021) Tao, Tao; Lindsey, Greg; Cao, Jason; Wang, JueyuExposure to risk is a theoretically important correlate of crash risk, but many safety performance functions (SPFs) for pedestrian and bicycle traffic have yet to include the mode-specific measures of exposure. When SPFs are used in the systematic approach to assess network-wide crash risk, the omission of the exposure potentially could affect the identification of high-risk locations. Using crash data from Minneapolis, this study constructs and compares two sets of SPFs, one with pedestrian and bicycle exposure variables and the other without, for network-wide intersection and mid-block crash models. Inclusion of mode-specific exposure variables improves model validity and measures of goodness-of-fit and increases accuracy of predictions of pedestrian and bicycle crash risk. Including these exposure variables in the SPFs changes the distribution of high-risk locations, including the proportion of high-risk locations in low-income and racially concentrated areas. These results confirm the importance of incorporating exposure measures within SPFs and the need for pedestrian and bicycle monitoring programs to generate exposure data.Item Modeling Bicyclist Exposure to Risk and Crash Risk: Some Exploratory Studies(Center for Transportation Studies, University of Minnesota, 2018-07) Lindsey, Greg; Wang, Jueyu; Hankey, Steven; Pterka, MichaelThis report presents models for estimating bicyclist exposure to risk and crash risk. Direct demand models for estimating weekday PM peak-period bicyclist exposure to risk are estimated from a database of PM peak-period bicycle counts in Minneapolis and used to estimate exposure for the street network. Bicycle crashes in Minneapolis are described and crash risk is assessed. Probability models to assess crash risk at both intersections and along segments show that both bicyclist exposure and vehicular exposure are associated with the likelihood of a bicycle crash. Estimates of exposure at 184 roadway-trail crossings are used to apply warrants for traffic controls. The results show that warrants for traffic signals and pedestrian hybrid beacons are most likely to be met using weekend peak-hour traffic flows. Most locations that meet warrants already have controls, but site specific safety investigations may be warranted at 9% of all crossings. Count-based models of bicyclist exposure are estimated for Duluth using origin-destination centrality indices as explanatory variables. Although these indices correlate positively and significantly with bicyclist volumes, estimates of exposure do not correlate with bicycle crashes. Together, these analyses illustrate how measures of bicyclist exposure to risk can be used in assessments of safety and crash risk. The approaches can be used in planning-level studies where consistent measures of exposure or risk are needed. These results underscore the need to continue bicycle traffic monitoring and make available estimates of exposure for safety assessments.Item Pedestrian and Bicycle Crash Risk and Equity: Implications for Street Improvement Projects(2019-06) Lindsey, Greg; Tao, Tao; Wang, Jueyu; Cao, JasonTransportation managers need information about crash risk and equity to prioritize investments in street networks. This case study uses data from Minneapolis, Minnesota, to illustrate how estimates of pedestrian and bicycle crash risk and assessments of inequities in the distribution of that risk can inform prioritization of street improvement projects. Crash numbers and frequencies for pedestrian and bicycle crashes at intersections and mid-blocks in Minneapolis are determined for the 2005-2017 period. New models of pedestrian and bicycle crash risk at both intersections and mid-blocks that control for exposure are introduced and used to predict crashes at all intersections and mid-blocks in the city. Statistical tests are used to assess the equity of distribution of estimated crash risk between areas of concentrated poverty with majority-minority populations and other areas in the city. Crash indexes based on predicted crashes are used to illustrate how increased emphases can be placed on pedestrian and bicycle safety in street improvement rankings. Results show that pedestrian and bicycle crash risk is correlated with exposure, that different factors affect crash risk at intersections and mid-blocks, and that these factors differ for pedestrian and bicycle crashes. Results also show that mean crash risk is higher in neighborhoods with lower incomes and majority-minority populations. For street improvement projects in the city, different rankings result when segments are ranked according to modeled pedestrian and bicycle crash risk in addition to total crash rates based on historical numbers of crashes at particular locations. Results generally affirm efforts by the Minneapolis Department of Public Works to increase emphases on pedestrian and bicycle safety and equity in its prioritization of street improvements.