Socio-economic disparities in activity-travel behavior adaptation during the COVID-19 pandemic in North Carolina.

The COVID-19 pandemic significantly affected human mobility. This study examines the changes in people's activity-travel behavior over 23 months (from Jan 2020 to Nov 2021) and how these changes are associated with the socio-economic status (SES) at the block group level in North Carolina. We identified 5 pandemic stages with different restriction regimes: the pre-pandemic, lockdown, reopening stage, restriction, and complete opening stage. Using the block-group mobility data from SafeGraph, we quantify visits to 8 types of destinations during the 5 stages. We construct regression models with interaction terms between SES and stages and find that visit patterns during the pandemic vary for different types of destinations and SES areas. Specifically, we show that visits to retail stores have a slight decrease for low and medium SES areas, and visits to retail stores and restaurants and bars bounced back immediately after the lockdown for all SES areas. The results suggest that people in low SES areas continued traveling during the pandemic. Transportation planners and policymakers should carefully design the transportation system to satisfy travel needs of those residents. Furthermore, the results also highlight the importance of designing mitigation policies that recognize the immediate recovery of visits to retail locations, restaurants, and bars.

Association between Neighborhood Food Access, Household Income, and Purchase of Snacks and Beverages in the United States.

Considerable research on the risk factors of obesity and chronic diseases has focused on relationships between where people live, where they shop, and the types of food they purchase. Rarely have investigators used a national sample and explicitly addressed the amount of energy-dense and nutrient-poor foods purchased in different types of neighborhood food stores. Even more rarely have studies accounted for the characteristics of the broader built environment in which food stores are located and which affect the convenience of using neighborhood food stores. We used a large population-based cohort of predominantly white U.S. households from the Nielsen Homescan Consumer Panel 2010 dataset to examine whether there were positive cross-sectional associations between availability of neighborhood convenience stores and supermarkets and self-reported household annual expenditures for snacks and beverages. We examined this relationship separately for poor and non-poor households as defined by the 2010 U.S. federal poverty threshold. We used mixed error-component regression models to examine associations between availability of neighborhood food stores and the expenditures on snacks and beverages, controlling for regional destination accessibility, availability and diversity of neighborhood destinations, and neighborhood street connectivity. In multivariate analyses, we observed that poor households in neighborhoods with few convenience stores purchased more snacks than poor households in neighborhoods with many convenience stores (b = -0.008, p < 0.05). Non-poor households in neighborhoods with many convenience stores and fewer supermarkets purchased more snacks than non-poor households in neighborhoods with few convenience stores and many supermarkets (b = 0.002, p < 0.05 for convenience stores; b = -0.027, p < 0.05 for supermarkets). Increase in number of convenience stores decreased the purchase of snacks by poor households, but increased in non-poor households. On other hand, increase in number of supermarkets discouraged purchase of snacks by non-poor households but had no effect on the purchasing behavior of the poor-households.Therefore, evaluation of access to energy-dense and nutrient-poor foods should include a consideration of geographic proximity. Local governments should consider strategies to expand the availability and access to nutrient-rich food and beverage products in convenience stores for consumers.

Does removal of federal subsidies discourage urban development? An evaluation of the US Coastal Barrier Resources Act.

Urban development relies on many factors to remain viable, including infrastructure, services, and government provisions and subsidies. However, in situations involving federal or state level policy, development responds not just to one regulatory signal, but also to multiple signals from overlapping and competing jurisdictions. The 1982 U.S. Coastal Barrier Resources Act (CoBRA) offers an opportunity to study when and how development restrictions and economic disincentives protect natural resources by stopping or slowing urban development in management regimes with distributed authority and responsibility. CoBRA prohibits federal financial assistance for infrastructure, post-storm disaster relief, and flood insurance in designated sections (CoBRA units) of coastal barriers. How has CoBRA's removal of these subsidies affected rates and types of urban development? Using building footprint and real estate data (n = 1,385,552 parcels), we compare density of built structures, land use types, residential house size, and land values within and outside of CoBRA units in eight Southeast and Gulf Coast states. We show that CoBRA is associated with reduced development rates in designated coastal barriers. We also demonstrate how local responses may counteract withdrawal of federal subsidies. As attention increases towards improving urban resilience in high hazard areas, this work contributes to understanding how limitations on infrastructure and insurance subsidies can affect outcomes where overlapping jurisdictions have competing goals.

Demarcating geographic regions using community detection in commuting networks with significant self-loops.

We develop a method to identify statistically significant communities in a weighted network with a high proportion of self-looping weights. We use this method to find overlapping agglomerations of U.S. counties by representing inter-county commuting as a weighted network. We identify three types of communities; non-nodal, nodal and monads, which correspond to different types of regions. The results suggest that traditional regional delineations that rely on ad hoc thresholds do not account for important and pervasive connections that extend far beyond expected metropolitan boundaries or megaregions.

Availability of neighbourhood supermarkets and convenience stores, broader built environment context, and the purchase of fruits and vegetables in US households.

OBJECTIVE: To determine whether neighbourhood supermarket and convenience store availability and broader built environment context are associated with food purchasing behaviour in a national population. DESIGN: We used observational data to perform a cross-sectional study of food purchases for US households in 2010. We used three-level mixed-effect regression models to determine whether the associations between the number of neighbourhood supermarkets and convenience stores and the self-reported annual household expenditures for fruits and vegetables were affected by regional destination accessibility, neighbourhood destination diversity, availability of neighbourhood destinations and neighbourhood street connectivity. SETTING: Metropolitan statistical areas (n 378) in the USA. PARTICIPANTS: Households (n 22 448). RESULTS: When we controlled for broader built environment context, there was no significant association between availability of neighbourhood supermarkets and expenditures on fruits and vegetables; instead, we observed an inverse association between the number of convenience stores and expenditures for fruits (P = 0·001). The broader built environment context was associated with food purchase, although the magnitude was small: (i) higher regional destination accessibility was associated with higher expenditures for fruits (P < 0·001); (ii) higher neighbourhood destination diversity was associated with lower expenditures for vegetables (P = 0·002); and (iii) higher neighbourhood street connectivity was associated with higher expenditures for fruits (P < 0·001). CONCLUSIONS: The broader built environment factors contributed to understanding how people use neighbourhood food stores. However, there was only a small relationship between the broader environment context and fruit and vegetable expenditures. Policy interventions that focus exclusively on increasing the availability of neighbourhood supermarkets likely will not promote fruit and vegetable consumption.

Missing millions: undercounting urbanization in India.

The measurement and characterization of urbanization crucially depends upon defining what counts as urban. The government of India estimates that only 31% of the population is urban. We show that this is an artifact of the definition of urbanity and an underestimate of the level of urbanization in India. We use a random forest-based model to create a high-resolution (~ 100 m) population grid from district-level data available from the Indian Census for 2001 and 2011, a novel application of such methods to create temporally consistent population grids. We then apply a community-detection clustering algorithm to construct urban agglomerations for the entire country. Compared with the 2011 official statistics, we estimate 12% more of urban population, but find fewer mid-size cities. We also identify urban agglomerations that span jurisdictional boundaries across large portions of Kerala and the Gangetic Plain.

Evaluating the impacts of the clean cities program.

The Department of Energy's Clean Cities program was created in 1993 to reduce petroleum usage in the transportation sector. The program promotes alternative fuels such as biofuels and fuel-saving strategies such as idle reduction and fleet management through coalitions of local government, non-profit, and private actors. Few studies have evaluated the impact of the program because of its complexity that include interrelated strategies of grants, education and training and diversity of participants. This paper uses a Difference-in-Differences (DiD) approach to evaluate the effectiveness of the program between 1990 and 2010. We quantify the effectiveness of the Clean Cities program by focusing on performance measures such as air quality, number of alternative fueling stations, private vehicle occupancy and transit ridership. We find that counties that participate in the program perform better on all these measures compared to counties that did not participate. Compared to the control group, counties in the Clean Cities program experienced a reduction in days with bad air quality (3.7%), a decrease in automobile commuters (2.9%), an overall increase in transit commuters (2.1%) and had greater numbers of new alternative fueling stations (12.9). The results suggest that the program is a qualified success.

The land value impacts of wetland restoration.

U.S. regulations require offsets for aquatic ecosystems damaged during land development, often through restoration of alternative resources. What effect does large-scale wetland and stream restoration have on surrounding land values? Restoration effects on real estate values have substantial implications for protecting resources, increasing tax base, and improving environmental policies. Our analysis focuses on the three-county Raleigh-Durham-Chapel Hill, North Carolina region, which has experienced rapid development and extensive aquatic ecological restoration (through the state's Ecosystem Enhancement Program [EEP]). Since restoration sites are not randomly distributed across space, we used a genetic algorithm to match parcels near restoration sites with comparable control parcels. Similar to propensity score analysis, this technique facilitates statistical comparison and isolates the effects of restoration sites on surrounding real estate values. Compared to parcels not proximate to any aquatic resources, we find that, 1) natural aquatic systems steadily and significantly increase parcel values up to 0.75 mi away, and 2) parcels <0.5 mi from EEP restoration sites have significantly lower sale prices, while 3) parcels >0.5 mi from EEP sites gain substantial amenity value. When we control for intervening water bodies (e.g. un-restored streams and wetlands), we find a similar inflection point whereby parcels <0.5 mi from EEP sites exhibit lower values, and sites 0.5-0.75 mi away exhibit increased values. Our work points to the need for higher public visibility of aquatic ecosystem restoration programs and increased public information about their value.

Peak oil, urban form, and public health: exploring the connections.

We assessed the relationships between peak oil and urban form, travel behavior, and public health. Peak oil will affect the general economy, travel behavior, and urban form through income and substitution effects; however, because of the wide range of substitution possibilities, the impacts are likely to be gradual and relatively small. Furthermore, we suggest that changes in travel behavior and increases in urban density will have both favorable and unfavorable effects on public health. To mitigate the adverse impacts and to maximize the positive effects of peak oil, we recommend that careful attention should be paid to urban design and public health responses for a range of urbanization patterns.