> RESEARCH
My research focuses on how urban planning and technology influence our health and wellbeing. I am particularly interested in applying the concept of cities as data to understand cities as invisible grids and overlapping networks made up of vast quantities of data from smartphones, wearable devices, crowdsourcing platforms, and real-time sensors. I am also interested in using cities as platforms to support innovation and co-design of urban spaces with citizens, businesses, and civic leaders towards building healthier and smarter communities.
My dissertation work, published in Transportation Research Part A: Policy and Practice, is one of the first to explore both positive and negative impacts of light rail transit on health and to illuminate potential trade-offs of mode shift and active travel. My goal is to bridge the gap between urban planning, public health, and data science to develop innovative policy solutions to modern challenges, from promoting healthy behaviors to reducing environmental health risks.
My research is highly interdisciplinary and guided by the Social-Ecological Model that provides the framework for understanding the multiple levels of a social system and interactions between individuals and the environment. With this theoretical framework, I focus on the following key research questions:
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How does urban infrastructure influence mobility and health behavior?
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Does urban development exacerbate or mitigate environmental health risks?
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What are the opportunities and challenges of new technology?
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Can informatics offer new insights into urban planning and public health?
Methodologically, I use experimental research design and spatial data analytics to visualize and understand the relationships between cities, technology, and health. Below, I showcase my research projects in each topic area.
1. How does urban infrastructure influence mobility and health behavior?
Neighborhood walkability, driving, and sedentary behavior in mid-size Canadian Cities
Andy Hong, Lawrence D. Frank
Most Americans drive occasionally and spend an average of 47 minutes driving daily (Triplett, Rosenbloom, & Tefft, 2016). Although driving is important for daily mobility, time spent in cars is linked to sedentary lifestyle and a broad range of health risk factors, such as obesity and cardiovascular mortality (Warren et al., 2010). Previous studies indicate that neighborhood walkability may help reduce the negative impact of driving by allowing residents to walk more (Frank, Andresen, & Schmid, 2004) and to reduce TV viewing time (Sugiyama, Salmon, Dunstan, Bauman, & Owen, 2007). However, few studies have examined the role of the built environment in reducing sedentary behavior due to time spent in cars. This study examines the impact of the built environment on the relationship between driving time and sedentary behavior. Data for this study have been drawn from 1,097 individuals who participated in the NEWPATH study conducted in the Region of Waterloo, Canada. A series of multiple linear regression models were estimated to model physical activity and sedentary time as a function of driving time, with an interaction term for neighborhood walkability measures. The results indicate that neighborhood walkability moderates the relationship between driving time and sedentary behavior. This suggests that the highly walkable neighborhood has some protective effect of reducing sedentary behaviour due to increased driving time. Results inform planners and policy makers about the importance of the built environment in not only promoting physical activity but also reducing sedentary behavior, each of which has independent effect on health.
Publications:
Preparing a manuscript for submission to Transportation Research Part A
New light rail transit and active travel: A longitudinal study
Authors: Andy Hong, Marlon Boarnet, Douglas Houston
We use panel data to investigate the before-and-after impact of a new light rail transit line on active travel. Participants were divided into a treatment group and a control group (residing < ½ mile and > ½ mile from a new light rail transit station, respectively). Self-reported walking (n=204) and accelerometer-measured physical activity (n=73) were obtained for both groups before and after the new light rail transit opened. This is the first application of an experimental-control group study design around light rail in California, and one of the first in the U.S. Our panel design provides an opportunity for stronger causal inference than is possible in the much more common study designs that use cross-sectional data. It also provides an opportunity to examine how an individual’s previous activity behavior moderates the role that new light rail transit access plays in promoting active travel behavior. The results show that, when not controlling for subject’s before-opening walking or physical activity, there was no significant relationship between treatment group status and after-opening walking or physical activity. However, when controlling for an interaction between baseline walking/physical activity and treatment group membership, we found that living within a half-mile of a transit station was associated with an increase in walking and physical activity for participants who had previously low walking and physical activity levels. The results were opposite for participants with previously high walking and physical activity levels. Future policy and research should consider the possibility that sedentary populations may be more responsive to new transit investments, and more targeted approaches in transit service would be needed to encourage people to make healthy travel choices.
Publications
In the media:
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CityLab. 2016. When Light Rail Opens, Do People Really Get More Exercise? http://www.citylab.com/commute/2016/09/when-light-rail-opens-do-people-really-get-more-exercise/499139/
Evaluating the causal relationship between the built environment and health care costs in British Columbia
Authors: Andy Hong and Larry Frank
This study investigates the relationship between the built environment and annual health care utilization costs in the Vancouver metropolitan region. Specifically, we seek to evaluate the causal impacts of the built environment (environmental risk) and physical activity (behavioral risk) on disease outcomes and healthcare costs. This study leverages the BC Generations Project, the largest longitudinal health study in British Columbia that follows a cohort of nearly 30,000 BC participants over the next 30 years. This study links the baseline BC Generations cohort with medical data drawn from the British Columbia Medical Services Plan (MSP) with prescription costs extracted from PharmaNet. This study also uses PharmaNet database which details the costs of a comprehensive list of drugs and supplies prescribed by medical practitioners, and includes additional costs related to chronic diseases such as diabetes. Results of this study will offer insight into potential modifications to the built environment that would likely reduce the economic burden of illnesses in Canada.
Funding Agency: The Canadian Institutes of Health Research (Equivalent of NIH in the U.S.) provides funding for this research (CAD $289,323).
Partnership/Data Providers: Highly confidential health and medical data are provided by BC Generations and Population Data BC.
Publications:
Preparing a manuscript for publications in Environmental Health Perspectives
Authors: Dohyung Kim, JiYoung Park, Andy Hong
This study examines how built environment factors at trip destinations influence nonmotorized travel behavior in the City of Long Beach, California. Using 2008–2009 National Household Travel Survey with California Add-Ons, we found that nonmotorized users tend to choose more clustered destinations than motorized users, and that density, diversity, and design at destinations significantly affect mode choice decisions. Transportation networks and nonmotorized facilities at trip destinations are especially important factors for nonmotorized mode choice. Future policy and research need to consider built environment factors at trip destinations to effectively accommodate nonmotorized travel within a city.
2. Does urban development exacerbate or mitigate environmental health risks?
Noise and the City: Spatiotemporal relationship between urban development and residential noise using crowd-sourced 311 data
Hong, Andy, Byoungjun Kim, and Michael Widener
Noise is one of the most frequently complained nuisances and public health hazards in many cities (Adams et al., 2006). Chronic exposure to noise is known to increase stress levels (Schmidt et al., 2013), and even low-level background noise can cause annoyance, increase stress levels, and decrease work productivity (Baliatsas, van Kamp, van Poll, & Yzermans, 2016). While noise from traffic sources is often monitored and managed by physical intervention, noise from construction is often regulated by noise control bylaws, which typically prohibits construction activities during sleeping hours and holidays. Although construction activities are occasional across the city, citizens may be exposed to such nuisance consistently, especially when the city is growing rapidly. Given this background, this study investigates spatiotemporal relationship between urban development and neighborhood noise. We first assess the urban development patterns from the historical inventory of major development projects (2005 – 2016) in British Columbia. To understand neighborhood noise, this study takes advantage of a crowd-sourced 3-1-1 call data, a general hotline regarding maintenance issues in the city. Testing the linkage between building construction data with crowd-sourced noise data is a novel approach to examine the impact of urban developments on acoustical environments. Results inform planning policies and decisions for determining how effective urban noise regulations are and where to target more consorted effort to mitigate noise pollution in a rapidly growing city.
Publications
Preparing a manuscript for submission to Environment and Planning A
Effect of open streets events in Los Angeles on local air quality
Andy Hong, Suresh Ratnam, Scott Fruin
Open streets initiatives, which temporarily close streets to car traffic but open to other modes of transport, have recently gained popularity as a means of promoting physical activity and bicycling. However, few studies have examined the impact of open streets on air pollution. This study investigates air pollution and traffic impacts of three open streets events in Los Angeles, California. Using a real-time mobile monitoring platform and a backpack outfitted with portable instruments, air pollution (particulate mass below 2.5 and 10 um; ultrafine particle number (UFP); black carbon; and particle-bound polycyclic aromatic hydrocarbons) was measured before, during, and after each CicLAvia event. Results show that the CicLAvia events generally served as a traffic magnet, creating more traffic congestion than what is seen on typical Sundays. Events in Culver City and Downtown Los Angeles (DTLA) showed lower speeds and a 21 - 23% reduction in PM10, but increased traffic and an 18% and 30% increase in UFP during the Culver City and DTLA events, respectively. Overall, however, results indicate that large-scale events that close selected streets to traffic, while attracting significant numbers of vehicles and disrupting normal traffic flow on adjacent streets, can successfully have minor impacts to air quality if the average fleet emissions are as low as they are currently in Los Angeles.
Publications
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Manuscript competed, scheduled to be submitted to the Science of the Total Environment in Winter 2017
Impact of shift from car to light rail on air pollution exposure: An experimental study
Authors: Andy Hong
Light rail transit (LRT) has a reputation for being greener and healthier than automobile. However, very few empirical studies have examined the effects of shift from car to LRT on air pollution exposure. In this paper, I ask how much reduction of air pollution exposure can be achieved through mode shift from car to LRT. To answer this question, I conduct a controlled experiment using four plausible scenarios of mode shift and compare the differences through field measurements and Monte Carlo simulations. Results suggest that the effects of mode shift can be significantly altered by individual micro behaviors, such as ventilation setting and travel route choice. Results inform future research and practice regarding the importance of commuter’s micro behavior in assessing the health effects of mode shift from car to LRT.
Publications
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Manuscript under submission in Transportation Research Part D.
Impact of temporary freeway closure on regional air quality: A lesson from Carmageddon in Los Angeles, United States
Andy Hong, Lisa Schweitzer, Lindsey Marr, Wan Yang
Large cities in the United States face multiple challenges in meeting federal air quality standards. One difficulty arises from the uncertainties in evaluating traffic-related air pollution, especially the formation of secondary pollutants such as ozone and some particulate matter. Current air quality models are not well suited to evaluate the impact of a short-term traffic change on air quality. Using regional traffic and ambient air quality data from Southern California, we examine the impact of a two-day freeway closure on traffic and several criteria air pollutants (CO, NO2, O3, PM10, PM2.5). The results indicate that regional traffic decreased about 14% on average during the closure. Daily average PM2.5 levels decreased by about 32%, and daily 8 h maximum ozone levels decreased by about 16%. However, the daily 1 h maximum NO2 concentration was higher at some sites during the closure. Despite the mixed results with NO2, this study provides empirical evidence to support traffic reduction as an effective strategy to address chronic air pollution problems, especially with regard to ozone, in Southern California.
Exposure of bicyclists to air pollution in Seattle, Washington: Hybrid analysis using personal monitoring and land use regression
Authors: Andy Hong, Christine Bae
The increase in urban bicycling facilities raises public health concerns for potential exposure of bicyclists to traffic emissions. For an assessment of bicyclists’ exposure to local traffic emissions, a hybrid approach is presented; it combines personal monitoring and a land use regression (LUR) model. Black carbon, a proxy variable for traffic-related air pollution, was measured with an Aethalometer along the predesignated bicycle route in Seattle, Washington, for 10 days, during a.m. and p.m. peak hours (20 sampling campaigns). Descriptive statistics and three-dimensional pollution maps were used to explore temporal variations and to identify pollution hot spots. The LUR model was developed to quantify the influence of spatial covariates on black carbon concentrations along the designated route. The results indicated that the black carbon concentrations fluctuated throughout the sampling periods and showed statistically significant diurnal and monthly patterns. The hot spot analysis suggests that proximity to traffic and other physical environments have important impacts on bicyclists’ exposure and demand further investigation on the localized effects of traffic emissions on exposure levels. The LUR model explains 46% of the variations in black carbon concentrations, and significant relationships are found with types of bicycle route facility, wind speed, length of truck routes, and transportation and utility land uses. This research is the first application of the LUR approach in quantifying bicyclists’ exposure to air pollution in transport microenvironments. This study provides a rationale for encouraging municipalities to develop effective strategies to mitigate the health risks of exposure to local traffic emissions in complex urban bicycling environments.
Publications
Hong, E. Andy and Bae, C.-H Christine. 2012. Exposure of bicyclists to air pollution in Seattle, Washington: Hybrid analysis using personal monitoring and land use regression. Transportation Research Record, No. 2270, pp. 59-66.
3. What are the opportunities and challenges of new technology?
Transit in the age of shared mobility: Are ride-sharing and public transit mutually supportive?
Andy Hong, Sandip Charabarti
Shared mobiility services, such as Uber and Lyft, are taking over the urban transportation market by storm. They are quickly penetrating into urban transportation market, traditionally occupied by taxi cabs, public transit, and paratransit. According to the Wall Street Journal, Uber has reached almost 100,000 daily trips this year, which are one fourth of the total trips being generated by the yellow cab. This dramatic increase in mode share by shared mobility services is likely to continue because of their fast, easy, and affordable services as well as growing demand for flexible mobility among younger generation. The purpose of this paper is to explore whether shared mobility services compete against public transit and whether this competition negatively affects public transit ridership. We will use publicly available shared mobility services' trip data through NYC Taxi and Limousine Commission, geo-coded subway station and bus stop data from NYC Metropolitan Transportation Authority (MTA). To estimate transit ridership, we will also use historical weekly turnstile data from NYC MTA.
Please click this link to see the interactive map of NYC Subway ridership in 2014. The map was created using the publicly available NYC MTA weekday ridership statistics and neighborhood GIS data.
Health and equity implications of autonomous vehicles: An population-based modeling approach
Andy Hong and Wenwen Zhang
Autonomous vehicles are getting much attention in media for their potential to improve quality of life. Autonomous vehicles can allow people to maximize their time during travel and improve traffic safety by removing human errors, such as distracted driving or drunk driving. However, autonomous vehicles may present significant challenges to health professionals who have been focusing on reducing sedentary behavior. Once autonomous vehicles become a ubiquitous and affordable form of transportation, more people will switch to cars, and the majority of the mode shift will likely come from transit riders, cyclists, or pedestrians. This is a serious problem because reduction in modal share of active transportation, e.g. cycling, walking, and public transit, will result in increasing sedentary behaviors and may introduce systematic bias against certain groups of people. Autonomous vehicles may be beneficial for making our lives more convenient, but they will likely increase our reliance on automobiles, resulting in more sedentary behavior that adversely affects our health. Given this backdrop, this study investigates potential health and equity implications of autonomous vehicles by using a population-based modelling approach. We develop simulation models based on several assumptions about population-level mode choice and physical activity. The models will be validated by national travel and health surveys, such as National Household Transportation Survey (NHTS) and Behavioral Risk Factor Surveillance System (BRFSS). Results will inform health professionals and urban planners potential implications of autonomous vehicles on population-level health, physical activity, and health disparities.
Publications:
A manuscript being prepared for the Journal of Transport and Health. Model development and analysis phase.
4. Can informatics offer new insights into urban planning and public health?
CitySensor: Development and Pilot Testing of Urban Environmental Sensor using Open-source Hardware and Software
Authors: Andy Hong
The field of environmental sensing has received increased attention recently with advances in sensing and data analytics. In the application of air quality management, environmental sensing, combined with the Internet of Things (IoT) technology, has the potential to revolutionize how regulatory agencies control and manage air pollution. Environmental Protection Agencies (EPA) has long relied on very expensive air monitoring instruments to measure ambient levels of various air pollutants. This approach, although accurate and precise, is not capable of measuring the actual conditions of urban air quality because the measurement location is too far away from the sources of air pollution. IoT approaches allow scientists and field operators to deploy sensors closer to pollution sources and make informed decisions on where and how to target strategies to reduce air pollution. However, no standards or protocols have been established to allow scalable implementation of IoT-based sensor platforms. This project seeks to develop an open-source platform that is flexible enough to support a variety of needs for the development of IoT-based environmental sensor.
Publications:
Preparing a manuscript for submission to Sensors
Top-down or bottom-up? Difference between theory-based models and deep learning models for behavior prediction in health social networks
Authors: Andy Hong, Nhathai Phan, and Dejing Dou
Sedentary lifestyle is the fourth leading risk factor for global mortality. Physical inactivity is also responsible for 3.2 million deaths in the US. Therefore, one of the most important health policy goals is to reduce sedentary behavior and to encourage more active lifestyles. Many interventions have been suggested to curb sitting and driving long hours, such as increasing the supply of walk/bike facilities, Walk/Bike to School programs, trip reduction programs, and etc. Recently, social network has been suggested as a critical element in shaping and influencing behavioral determinants of physical inactivity and the risk of obesity. Previous research have focused on developing data-driven approach to identifying social network related to health behavior. However, few research have applied more traditional psychology-based theories to analyze social network in predicting physical activity behaviors. This study compares the efficacy of applying theory-based models (top-down) vs. data-driven deep learning models (bottom-up) for predicting health behaviors. Results will inform health researchers and data scientists the importance of applying both top-down and bottom-up approaches to understanding social network for predicting health-related behaviors.
Publications:
Preparing a manuscript for publication in health and information journals
Do urban planners collaborate with data scientists? Social network analysis using bibliometric data
Authors: Andy Hong, Kangpyo Lee, Chang-Yu Hong
Urban planners are increasingly turning their attentions to data science and new analytic techniques. With the advent of big data, Internet of Things, and open data movements, urban planning as a discipline is at a tipping point where radical transformation will likely occur in the next decades or so. Traditional research methods relying on surveys and focus groups will be replaced by new data sources and methods, such as mobile phone data, real-time sensing data, and crowd-sourced data. To make this transition successful, it is vital for urban planners to work and collaborate with people who are knowledgeable about the new methods, namely, data scientists. Data scientists, on the other hand, will need to collaborate with urban planners as they lack domain-specific expertise, which is critical for implementation of new technology at the city scale. This study explores the current state of collaboration between urban planners and data scientists through social network analysis of bibliometric data. Bibliometric data are essentially meta-data from journal articles, such as authors, publication date, abstract, and references. We will use centrality measure and betweenness measure to construct social networks between urban planners and data scientists at the journal level and at the individual level. Results will inform us to what extent collaboration occurs between the two disciplines, and will help us identify key players in this emerging scholarship.
Publications
Preparing a manuscript for Journal of Planning and Education Research