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Department: Urban Design and Planning

Does Accessibility Require Density or Speed?

Levine, J., Grengs, J., Shen, Q., & Shen, Q. (2012). Does Accessibility Require Density or Speed?. Journal of the American Planning Association, 78(2), 157–172.

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Abstract

Problem, research strategy, and findings: Advocates of accessibility as a transportation performance metric often assert that it requires higher density. Conversely, traditional transportation planning methods have valued speed per se as an indicator of success in transportation. In examining these claims, we make two methodological innovations. The first is a new intermetropolitan gravity-based accessibility metric. Second, we decompose the impact of density on accessibility to highlight the distinct opposing influences of speed and proximity in a manner that illustrates different families of relationships between these two factors. This reveals that denser metropolitan regions have slower travel speeds but greater origin-destination proximity. The former effect tends to degrade accessibility while the latter tends to enhance it. Despite theoretical reasons to expect that the speed effect dominates, results suggest that the proximity effect dominates, rendering the denser metropolitan areas more accessible.

Takeaway for practice: Having destinations nearby, as when densities are high, offers benefits even when the associated congestion slows traffic. Where land use policy frequently seeks to support low-development densities in part in an attempt to maintain travel speeds and forestall traffic congestion, our findings suggest that compact development can often improve transportation outcomes.

Research support: Environmental Protection Agency project RD-83334901-0, FHWA Cooperative Agreement Number: DTFH61-07-H-00037, and the Graham Environmental Sustainability Institute at the University of Michigan.

Keywords

accessibility; mobility; speed; proximity; transportation planning

Transit-Oriented Development at the Urban Periphery: Insights from a Case Study in Shanghai, China

‌Pan, H., Shen, Q., & Liu, C. (2011).. Transit-Oriented Development at the Urban Periphery: Insights from a Case Study in Shanghai, China. Transportation Research Record: Journal of the Transportation Research Board, 2245(1), 95–102.

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Abstract

Major cities in China are extending rail transit into the urban periphery to counter urban growth and suburbanization that are automobile-driven and automobile-dependent. In the meantime, transit-oriented development (TOD) has been adopted widely in Chinese cities. Given the adoption of the TOD concept by many rail transit station areas at the peripheries of metropolitan regions, it is imperative to explore how TOD can be applied appropriately there. In this study, two station areas were examined in Songjiang, a district located approximately 30 km from the city center of Shanghai, China. These station areas have developed according to some basic TOD principles, and, in many important ways, they are representative of newly developed rail transit station areas in Shanghai and in other major Chinese cities. The conduct of a questionnaire survey allowed for investigation of resident travel behavior, assessment of the effectiveness of the TOD application, and discussion of how TOD should be adapted to peripheral locations in a large and complex metropolitan region. The study concluded that planners must carefully substantiate the basic TOD concept in connection with this particular kind of application setting. Careful consideration should be paid to mixed land use, differentiated density, and to pedestrian and bicycle travel and their connection with rail transit. Planners also must pay close attention to each peripheral area's economic and social conditions, as well as its relationships with the central city and with other parts of the metropolitan region. This case study not only provided timely feedback on current planning practice in Shanghai and other Chinese cities but also contributed to the literature on the adaptation of TOD to local circumstances.

 

How Urban Ecological Land Affects Resident Heat Exposure: Evidence from the Mega-urban Agglomeration in China

Feng, R., Wang, F., Liu, S., Qi, W., Zhao, Y., & Wang, Y. (2023). How Urban Ecological Land Affects Resident Heat Exposure: Evidence from the Mega-urban Agglomeration in China. Landscape and Urban Planning, 231.

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Abstract

Resident heat exposure (RHE) is becoming more severe in the coming decades owing to rapid urbanization and climate change. Urban ecological land (UEL) provides important ecosystem services, such as mitigating the urban heat islands effect. However, the impacts of UEL on RHE remain poorly understood. This study quantifies the effects of UEL and its interaction with the natural-anthropogenic environment on RHE in the Guangdong-Hong Kong-Macao Greater Bay Area, a mega-urban agglomeration in China. The results showed a tight spatial–temporal coupling between the UEL and RHE: UEL transitioned from degradation-fragmentation in 2000–2010 to recovery-agglomeration in 2010–2020, while the RHE distribution evolved from intensification-expansion-inequity to mitigation-contraction-equity. The average explanatory power (q value) of UEL and its structure on RHE also increased by 75.99% and 70.79%, respectively. UEL patch diversity gradually dominated the RHE distribution, and the spatial marginal effect of UEL dominance increased by 234.97%. Moreover, RHE shifted from being dominated by UEL and anthropogenic heat emissions interactions to being jointly driven by UEL and natural-anthropogenic factors (especially the interaction of patch fragmentation with topography and built-up land expansion). The results of this study provide valuable information for nature-based (i.e., UEL) landscape planning and management to develop “human-centric” RHE mitigation strategies.

Keywords

Urban ecological land; Resident heat exposure; Spatial-temporal effects; Natural-anthropogenic factors; Interaction effect; Mega-urban agglomeration

Rachel Berney and Jeff Hou contribute to new book on social justice in urban design

“Just Urban Design: The Struggle for a Public City” (MIT Press 2022) features a collection of chapters and case studies that apply a social justice lens to the design of urban environments. Sixteen contributors, including Rachel Berney of Urban Design & Planning and Jeff Hou of Landscape Architecture, examine topics ranging from single-family zoning and community capacity building to immigrant street vendors and the right to walk. The book is open-access and can be downloaded from MIT Press here.

Helping Rural Counties to Enhance Flooding and Coastal Disaster Resilience and Adaptation

In the United States, flooding is a leading cause of natural disasters, with congressional budget office estimates of $54 billion in loss each year. Although both urban and rural areas are highly vulnerable to flood hazards, most natural disaster resilience studies have focused primarily on urban areas, overlooking rural communities. One such area that has been overlooked are the numerous rural communities bordering the Great Lakes. These communities face unprecedented challenges due to rising water levels, particularly since 2012, which have resulted in increased coastal flood hazard. Despite their flooding risk, they continue to lack flood hazard assessments and inundation maps, exacerbating their vulnerability. The Federal Emergency Management Agency (FEMA) commonly recommend counties to use a freely available tool—called HAZUS to develop hazard mitigation plans and enhance community resilience and adaptation. However, the usage of HAZUS for rural communities is challenging  due to existing data gaps that limit the analytical potential of HAZUS in these communities. Continued use of standard datasets for HAZUS analysis by rural counties could likely leave the communities underprepared for future flood events. The proposed project’s vision is to develop methods that use remote sensing data resources and citizen engagement (crowdsourcing) to address current data gaps for improved flood hazard modeling and visualization that is scalable and transferable to rural communities.

The results of the project will expand the traditional frontiers of preparedness and resilience to natural disasters by drawing on the expertise and backgrounds of investigators working at the interface of geological engineering, civil engineering, computer science, marine engineering, urban planning, social science, and remote sensing. Specifically, the proposed research will promote intellectual discovery by i) improving our understanding of remote sensing data sources and open-source processing methods to assist rural communities in addressing the data gaps in flood hazard modeling, ii) developing sustainable geospatial visualization tools for communicating hazards to communities, iii) advancing our understanding of the utility of combining remote sensing and crowdsourcing to flood hazard delineation, iv) understanding ways to incentives the crowd for greater participation and accuracy in hazard in addressing natural disasters, and v) identifying critical community resilience indicators through crowdsourcing. These advancements will lead to prepared and resilient rural communities that can effectively mitigate hazards related to lake level rise and flooding.

Assessing the Expectations Gap – Impact on Critical Infrastructure Service Providers’ and Consumers’ Preparedness, and Response

While community lifeline service providers and local emergency managers must maintain coordinated response and recovery plans, their timelines may not match expectations of local consumers of lifeline services. Indeed, it is quite likely consumers have unrealistic expectations about lifeline restoration, which could explain current inadequate levels of disaster preparedness. This hypothesized expectation gap has received little attention because engineering research typically addresses providers’ capacities, whereas disaster research addresses household and business preparedness. Our project will address this neglected issue by assessing consumers’ (households, business owners/managers, nonprofit managers) expectations about lifeline system performance, and comparing them to lifeline provider capacity in a post-hazard event scenario (following a Cascadia subduction zone earthquake of 9.0 magnitude or greater) in two communities—Kirkland and Shoreline, WA (likely to experience most shaking in this scenario).

Our research will assess the role of the expectations gap in influencing consumers’ and providers’ preparedness as well as response. First, we estimate the gap between consumers and providers expectations using an earthquake scenario in two case study communities. We posit that low consumer preparedness for lifeline disruption is in part a function of low expectations that lengthy disruption will occur. Next, we test the effect of providing consumers and providers with information about this gap. Our proposed sharing estimates of lifeline restoration times should change these beliefs if our assumption about this specific basis for low preparedness is correct and if our audiences attend to, process, and act upon this information. In our longitudinal research, consumers (households, businesses, and nonprofits) and lifeline providers will complete two questionnaires each. Besides lifeline provider surveys, we will collect information about lifeline providers’ capabilities and work with them to estimate restoration times using an expert elicitation-based estimation framework. We will address the following research questions:

  1. What do consumers think is the likely level of critical lifeline disruption from an earthquake and the timeline for restoration?
  2. What are consumers’ current levels of preparedness for lifeline interruption?
  3. What do lifeline providers and an independent engineering expert think are providers’ capabilities to maintain and restore lifeline services?
  4. How do consumers’ expectations compare with providers’ capabilities (expectations gap)?
  5. How will this study’s feedback about the expectations gap affect consumers’ and providers’ lifeline resilience expectations, as well as their mitigation and preparedness intentions?

Using Open Data and Open-source Software to Develop Spatial Indicators of Urban Design and Transport Features for Achieving Healthy and Sustainable Cities

Boeing, Geoff; Higgs, Carl; Liu, Shiqin; Giles-corti, Billie; Sallis, James F.; Cerin, Ester; Lowe, Melanie; Adlakha, Deepti; Hinckson, Erica; Moudon, Anne Vernez; Salvo, Deborah; Adams, Marc A.; Barrozo, Ligia, V; Bozovic, Tamara; Delclos-alio, Xavier; Dygryn, Jan; Ferguson, Sara; Gebel, Klaus; Thanh Phuong Ho; Lai, Poh-chin; Martori, Joan C.; Nitvimol, Kornsupha; Queralt, Ana; Roberts, Jennifer D.; Sambo, Garba H.; Schipperijn, Jasper; Vale, David; Van De Weghe, Nico; Vich, Guillem; Arundel, Jonathan. (2022). Using Open Data and Open-source Software to Develop Spatial Indicators of Urban Design and Transport Features for Achieving Healthy and Sustainable Cities. Lancet Global Health, 10(6), E907-E918.

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Abstract

Benchmarking and monitoring of urban design and transport features is crucial to achieving local and international health and sustainability goals. However, most urban indicator frameworks use coarse spatial scales that either only allow between-city comparisons, or require expensive, technical, local spatial analyses for within-city comparisons. This study developed a reusable, open-source urban indicator computational framework using open data to enable consistent local and global comparative analyses. We show this framework by calculating spatial indicators-for 25 diverse cities in 19 countries-of urban design and transport features that support health and sustainability. We link these indicators to cities' policy contexts, and identify populations living above and below critical thresholds for physical activity through walking. Efforts to broaden participation in crowdsourcing data and to calculate globally consistent indicators are essential for planning evidence-informed urban interventions, monitoring policy effects, and learning lessons from peer cities to achieve health, equity, and sustainability goals.

Keywords

Systems; Access; Care

What Next? Expanding Our View of City Planning and Global Health, and Implementing and Monitoring Evidence-informed Policy

Giles-corti, Billie; Moudon, Anne Vernez; Lowe, Melanie; Cerin, Ester; Boeing, Geoff; Frumkin, Howard; Salvo, Deborah; Foster, Sarah; Kleeman, Alexandra; Bekessy, Sarah; De Sa, Thiago Herick; Nieuwenhuijsen, Mark; Higgs, Carl; Hinckson, Erica; Adlakha, Deepti; Arundel, Jonathan; Liu, Shiqin; Oyeyemi, Adewale L.; Nitvimol, Kornsupha; Sallis, James F. (2022). What Next? Expanding Our View of City Planning and Global Health, and Implementing and Monitoring Evidence-informed Policy. Lancet Global Health, 10(6), E919-E926.

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Abstract

This Series on urban design, transport, and health aimed to facilitate development of a global system of health-related policy and spatial indicators to assess achievements and deficiencies in urban and transport policies and features. This final paper in the Series summarises key findings, considers what to do next, and outlines urgent key actions. Our study of 25 cities in 19 countries found that, despite many well intentioned policies, few cities had measurable standards and policy targets to achieve healthy and sustainable cities. Available standards and targets were often insufficient to promote health and wellbeing, and health-supportive urban design and transport features were often inadequate or inequitably distributed. City planning decisions affect human and planetary health and amplify city vulnerabilities, as the COVID-19 pandemic has highlighted. Hence, we offer an expanded framework of pathways through which city planning affects health, incorporating 11 integrated urban system policies and 11 integrated urban and transport interventions addressing current and emerging issues. Our call to action recommends widespread uptake and further development of our methods and open-source tools to create upstream policy and spatial indicators to benchmark and track progress; unmask spatial inequities; inform interventions and investments; and accelerate transitions to net zero, healthy, and sustainable cities.