Environment

Impacts of Transportation Network Companies on Vehicle Miles Traveled, Greenhouse Gas Emissions, and Travel Behavior Analysis from the Washington D.C., Los Angeles, and San Francisco Markets

Martin, Elliot, PhD
Susan Shaheen
Stocker, Adam
2021

Transportation Network Companies (TNCs) like Lyft, Uber, and their global counterparts have expanded around the world over the past decade and have changed the way that people travel around cities and regions. The individual mobility benefits provided by TNCs have been clear. Passengers can summon a vehicle quickly via smartphone from almost anywhere to take them almost anywhere, with advance communication on estimated wait time, travel time, and cost. TNCs may also provide users with added mobility benefits, especially for those living in areas where public transit service is infrequent...

Power Trips: Early Understanding of Preparedness and Travel Behavior During California Public Safety Power Shutoff Events

Wong, Steven D.
Broader, Jacquelyn C.
Susan Shaheen
2022

Recent wildfire risks in California have prompted the implementation of public safety power shutoff (PSPS) events, procedures enacted by utility operators to de-energize parts of the electrical grid and reduce the likelihood of wildfire ignition. Despite their yearly occurrence, PSPS events are severely understudied, and little is known about how these events impact disaster preparation activity, travel behavior, and transportation systems. With growing wildfire risks in North America and beyond, PSPS events require immediate and thorough research to reduce their negative externalities and...

City-Level Impact of Extreme Temperatures and Mortality in Latin America

Kephart, JL
Sánchez, BN
Moore, J
Schinasi, L
Bakhtsiyarava, M
Ju, Y
Daniel Rodriguez
Gouveia, N
Caiaffa, W
Dronova, I
Arunachalam, S
Roux, AV Diez
2022

Climate change and urbanization are rapidly increasing human exposure to extreme ambient temperatures, yet few studies have examined temperature and mortality in Latin America. We conducted a nonlinear, distributed-lag, longitudinal analysis of daily ambient temperatures and mortality among 326 Latin American cities between 2002 and 2015. We observed 15,431,532 deaths among ≈2.9 billion person-years of risk. The excess death fraction of total deaths was 0.67% (95% confidence interval (CI) 0.58–0.74%) for heat-related deaths and 5.09% (95% CI 4.64–5.47%) for cold-related deaths. The...

Characterizing Determinants of Near-Road Ambient Air Quality for an Urban Intersection and a Freeway Site

Frey, HC
Grieshop, AP
Khlystov, A
Bang, JJ
Rouphail, N
Guinness, J
Daniel Rodriguez
Fuentes, M
Saha, P
Brantley, H
2022

Traffic emissions are an important source of urban air pollution, and exposure to traffic-related air pollution has been associated with various adverse health effects. However, exposure assessment is challenging because traffic-related air pollution is a complex mixture of many particulate and gaseous pollutants and is highly variable across locations and time. Developing accurate models of traffic-related air pollution for use in exposure assessment for epidemiological studies relies on understanding traffic activity and air flow at small spatial scales within cities. Dr. H. Christopher...

Advancing Social Equity and Congestion Relief: Understanding the Travel Needs of Underserved Populations That Rely on Transportation Network Companies in the San Francisco Bay Area

Susan Shaheen
Gosselin, Kate
Broader, Jacquelyn
Cohen, Adam
2022

Transportation Network Companies (TNCs) enable travelers to order and pay for rides on-demand using an online application that connects them with drivers using their personal vehicles. While these modes present opportunities to increase individual mobility and access, they also can worsen congestion and increase vehicle emissions. Researchers explored factors impacting the willingness to use pooled TNCs and identified strategies/policies that could be employed to reduce congestion from TNC use. Researchers conducted a literature review, interviews with TNC experts, semi-structured...

Ambient Nitrogen Dioxide Exposures in Latin American Cities

Kephart, JL
Gouveia, N
Daniel Rodriguez
Alfaro, T
Texcalac-Sangrador, JL
Miranda, J
Bilal, U
Roux, AV Diez
2022
Background and Aim: Ambient nitrogen dioxide (NO₂) is a ubiquitous urban air pollutant emitted by fossil fuel combustion. Exposure to NO₂ is associated with respiratory disease and all-cause mortality. Health research on ambient NO₂ is sparse in Latin America, despite high urbanization and the high prevalence of NO₂-associated respiratory diseases in the region. This study aims to describe highly-granular population exposures to ambient NO₂ and urban characteristics associated with NO₂ exposure within 326 Latin American cities. Methods: We leveraged estimates of annual surface NO₂ at 1km²...

Health and Environmental Co-Benefits of City Urban Form in Latin America: An Ecological Study

Avila-Palencia, I
Sánchez, BN
Daniel Rodriguez
Perez-Ferrer
Miranda, J
Gouveia, N
Bilal, U
Useche, A
Wilches-Mogollon, M
Moore, K
Sarmiento, O
Roux, AV Diez
2022
We investigated the association of urban landscape profiles with health and environmental outcomes, and whether those profiles are linked to environmental and health co-benefits. In this ecological study, we used data from 208 cities in 8 Latin American countries of the SALud URBana en América Latina (SALURBAL) project. Four urban landscape profiles were defined with metrics for the fragmentation, isolation, and shape of patches (contiguous area of urban development). Four environmental measures (lack of greenness, PM2.5, NO2, and carbon footprint), two...

Modification of Temperature-Related Human Mortality by Area-Level Socioeconomic and Demographic Characteristics in Latin American Cities

Bakhtsiyarava, M
Schinasi, LH
Sánchez, BN
Dronova, I
Kephart, JL
Ju, Y
Gouveia, N
Caiaffa, WT
O'Neill, MS
Yamada, G
Arunachalam, S
Roux, AV Diez
Daniel Rodriguez
2023

In Latin America, where climate change and rapid urbanization converge, non-optimal ambient temperatures contribute to...

Do Incentives Make a Difference? Understanding Smart Charging Program Adoption for Electric Vehicles

Wong, Steven D.
Susan Shaheen
Martin, Elliot PhD
Uyeki, Robert
2023

Climate change and environmental problems have spurred new strategies to reduce fossil fuel consumption in transportation. Two important strategies include a rapid transition to green energy and the replacement of internal combustion vehicles with electric vehicles (EVs). However, the increasing demand for electricity by EVs, especially from time-dependent green sources of energy (e.g., solar, wind), will likely overload the grid at peak hours. Rather than build costly infrastructure improvements for distribution and generation, smart charging programs for EVs could defer charging to off-...

Social Disparities in Flood Exposure and Associations with the Built Environment in 47,187 Urban Neighborhoods in Eight Latin American Countries

Kephart, JL
Bilal, U
Ferreira, A
Gouveia, N
Daniel Rodriguez
Barbieri, IS
Miranda, J
Roux, AV Diez
2023
BACKGROUND AND AIM: Climate change is expected to greatly increase population exposure to flooding and related health impacts, particularly in urban areas of the Global South. We aimed to examine within-city social disparities in exposure to flooding within 326 Latin American cities and associated features of the neighborhood environment. METHOD: We used a high spatial resolution dataset of historical flood events from 2000-2018 to describe flood exposure at the neighborhood level for all cities with 100,000+ residents in eight Latin American countries (Argentina, Brazil, Chile, Colombia,...