Background: Bike sharing systems have potential to substantially boost active transportation levels (and consequent physical and mental health) in urban populations. We explored equity of spatial access in a novel ‘dockless’ bike share system that does not that constrain bike pickup and drop-off locations to docking stations. Methods: Starting in July 2017, Seattle, Washington piloted a dockless bike share system that made 10,000 bikes available. We merged data on resident sociodemographic and economic characteristics from the American Community Survey about 93 defined neighborhoods with data about bike locations, bike idle time, and which neighborhoods operators rebalanced bikes to. We used mapping and descriptive statistics to compare access between neighborhoods along sociodemographic and economic lines. Results: With many bikes available, no neighborhood was consistently excluded from access. However, the average availability ranged from 3 bikes per day to 341 per day. Neighborhoods with more bikes had more college-educated residents (median 75% college-educated vs. 65%) and local community resources (median opportunity index score of 24 vs. 19), and higher incomes (median 83,202 vs. 71,296). Rebalancing destinations were strongly correlated with neighborhood demand (r=0.61). Conclusions: The overall scale of the dockless system ensured there was baseline access throughout Seattle. We observed modest inequities in access along sociodemographic lines, similar to prior findings in studies of docked bike share systems. Dockless bike share systems hold promise for offering equitable spatial access to bike sharing.

Freeway-related air pollution and its harmful health risks have been observed in recent research in the environmental-health sciences. In this study we investigate the impact of freeway and arterial-road air pollution on vulnerable populations—for example, the poor, minorities, children, and the elderly—whose housing options are limited. Because many mobile-source emissions decay rapidly with distance, approaching background concentrations at 330 ft from the freeway, populations living near limited access roads are most at risk from exposure. Furthermore, microscale air monitoring systems are rarely in place at these locations in the United States. In this research we will define freeway air-pollution sheds with the aid of a geographic information system analysis and determine populations that may be at risk from exposure to mobile-source pollutants in two West Coast metropolitan areas (Seattle and Portland). We then use cluster analysis to identify key neighborhoods at risk in Seattle. Subsequently, we apply a hedonic pricing model to understand the extent to which house price values in Seattle are related to freeway proximity. Finally, we discuss policy options, planning implications, and mitigation measures, including an assessment of air-quality monitoring needs and land-use prescriptions.

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A crucial element of sustainability is the optimization of system efficiency by the maximization of existing resources and the limitation of the necessity of infrastructure expansion. Although the Leadership in Energy and Environmental Design certification is an internationally recognized standard for determining sustainable architecture, no officially accepted method exists for evaluating sustainable transportation. The development of a performance evaluation method for sustainable transportation is necessary, with a focus on multimodal mobility rather than on automobility. It is crucial that current transportation projects not preclude the provision of multimodal mobility options in the future. This paper reviews the literature on operational and proposed evaluation strategies for transportation projects and proposes a sustainable transportation evaluation method. The sustainable transportation evaluation method builds on the observed beneficial qualities of the existing evaluation systems and attempts to address their shortcomings. Implementation of the sustainable transportation evaluation method relies on established multicriterion techniques that allow for quantitative and qualitative evaluation of the sustainability of transportation projects during the planning, design, and construction phases. The evaluation method proposed can augment traditional environmental analysis performed for transportation project selection. The method is designed to be flexible so that it can be easily implemented by a wide range of stakeholders who are considering diverse issues.