2013 Session: 351

• Using Urban Commuting Data to Calculate a Spatiotemporal Accessibility Measure for Healthy Food Environment Studies
  Abstract: Improving spatial access to healthy foods in urban regions in the U.S. is recognized as an important component of reducing the prevalence of chronic illness and achieving better health outcomes. Previously, researchers exploring this domain have calculated accessibility measures derived from the travel cost from home locations to nearby healthy food stores. While there are valid arguments for making home-based healthy food store accessibility measures, this approach disregards additional opportunities that present themselves to residents as they move throughout the city during the day. In this paper, a time-geographic accessibility measure is utilized to explore how single occupancy automobile commuting affords access to supermarkets. The study builds on recent research by analyzing the time available for grocery shopping given people’s intracity commuting trips. The paper focuses on how single occupancy automobile travel, the dominant form of commuting in the U.S., changes the picture of access to supermarkets in Cincinnati, OH, a city with a number of USDA designated food deserts. Time-geographic accessibility measures are reported at the TAZ-level and compared with an analogous home-based metric. Results show residents in some TAZs have more access when accounting for their commuting behavior than when measuring access from their home. This finding suggests that more nuanced calculations of accessibility are necessary to fully understand which urban populations have greater access to healthy food.
  Authors: Widener, Michael John; Farber, Steven; Neutens, Tijs; Horner, Mark W.
  Authors: Widener, Michael John; Farber, Steven; Neutens, Tijs; Horner, Mark W.
  Year: 2013
  Document Type: Paper
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-0825
• Integrated Analysis of Workers' Physically Active Activity and Active Travel Choice Behavior
  Abstract: Employing 2009 NHTS Texas add-on sample data, this study examines individual’s active choice decisions with a specific market focus on adult workers. This is achieved by examining worker’s two choice behaviors: active activity and active travel. The first choice behavior is developed as an ordered-response model based on the number of physically active recreational activities pursued during the workday. The second model is developed as a binary-response model that examines worker’s active travel choices; whether or not the worker used any active mode of travel during the same workday. The current study contributes to the field by improving our understanding and knowledge of factors influencing worker’s physically active activity-travel behavior. The study provides several insights regarding the role (and constraints) of employment in individual’s active choices while demonstrating that transportation and public health policy makers can mutually benefit from encouraging workers to be physically active (from an activity and/or travel perspective). Using a flexible and robust copula modeling methodology, we explore the ‘true’ correlation (or dependence) between the two behavior choices that might occur due to the presence of unobserved factors, in addition to the examination of various observed factors, suggesting a simultaneous low or simultaneously high propensity toward being physically active across workers. Overall, the study unifies and reveals the integrated nature of the public health and transportation fields thereby providing a distinct view of active/inactive choice behavior.
  Authors: Sener, Ipek Nese
  Authors: Sener, Ipek Nese
  Year: 2013
  Document Type: Paper
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-2213
• School Commute Air Quality: Understanding Variation in Pollutant Exposure for Students Traveling to School by Auto, Bus, or Walking
  Abstract: Student commute mode and route choice are important in determining commute safety as well as influencing student health, as recognized by the Safe Routes to School program. Little has been done, however, to examine the air pollution exposure impacts of student mode choice as students move throughout the roadway environment. This study examines differences in air pollutant exposure along three different routes for students commuting to school via auto, transit bus, and walking. Three pollutant types are included: PM2.5, ultrafine particles, and carbon monoxide. The route recommended by Safe Routes to School is inconsistently observed to have the lowest pollutant concentrations. Results indicate traveling along lower-volume roadways reduces walking exposure, while traveling along busier roadways results in exposure to greater pollutant concentrations. Walking exposure is found to be greater than driving exposure, but less than bus exposure. The maximum concentration for each pollutant was located along the most congested roadway. Pollutant concentrations for the walking mode are mapped to give visual representation of exposure fluctuations during a commute. This research reinforces the importance of selecting low-volume roadways for safety, but also to minimize exposure, and demonstrates a need for further research examining the factors that determine exposure along different street types ranging from arterial to neighborhood roadways. These results serve as a complement to existing environmental justice air quality research, serving as the link between exposure at the home and exposure at the school in urban areas.
  Authors: Moore, Adam; Figliozzi, Miguel
  Authors: Moore, Adam; Figliozzi, Miguel
  Year: 2013
  Document Type: Paper
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-3315
• Analysis of School Trip Mode Choice: Promoting Active Travel
  Abstract: Urban and transportation planners have put a special focus on student health and fitness in the past decade, however they struggle to find effective policies to promote walking and biking for school trips. Commuting to school is an opportunity to embed a regular physical activity in students’ daily routines and prevent many health issues that are stimulated by a lack of physical activity during childhood. A three level nested logit model is introduced to explain the motives behind school trip modal selection. Four choice situations, namely walking, driving, school busing, and taking public transit are considered. We, particularly, underscored the significance of model misspecification in terms of policy outcomes, since multinomial logit models are typically adopted in the literature and have strong and, in many cases, unrealistic assumptions. For instance, elasticity analysis of the MNL model showed an indirect elasticity of vehicle ownership of -0.13 in the MNL model, while NL model provides different elasticities of -0.12, -0.20, and -0.08, respectively for public, school bus, and walk modes. This misspecification results in over estimating the reduction in the share of students who walk to school when vehicle ownership increases. Moreover, a wide range of policy-sensitive variables along with their effect magnitude was discussed and compared with the previous studies. Particularly, we found that one percent increase in the probability of walking to school is expected for every 0.046 percent increase in auto travel time, 0.075 percent increase in the normalized-to-income cost of driving, 0.088 percent decrease in vehicle ownership, 0.033 percent increase in distance to public transit, or 2.372 percent decrease in commute distance. Safety was also found to be very influential on active commuting, such that addressing the safety concern of parents is expected to increase propensity of active commuting to school by around 60 percent.
  Authors: Samimi, Amir; Ermagun, Alireza
  Authors: Samimi, Amir; Ermagun, Alireza
  Year: 2013
  Document Type: Paper
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-3618
• Relationship Between Measures of Urban Form and Body Mass Index in Nonurban Diabetic Adults: Case Study from Vermont
  Abstract: We analyzed the relationship between measures of urban form and body mass index (BMI) using data from the Vermont Diabetes Information System (VDIS) on 610 adult diabetics, while controlling for a number of potential confounders, including diet, exercise, income, gender, age, medications, and others. We found a strong positive correlation between BMI and commercial density measured at a 250 meter scale, a result which remained significant even when spatial autocorrelation was accounted for. This result, which is contrary to much of the previous literature, suggests that the mechanism driving the relationship between BMI and density is different in a predominantly rural and exurban region like Vermont than in a large metropolitan area, which is where most of the previous literature was conducted. We hypothesize that the lack of a significant alternative to automobile transport coupled with a dispersed land use pattern means that marginal increases in density in most areas of Vermont are unlikely to lead to significantly greater walkability or active transport. Further, low commercial density may proxy greater access to outdoor recreation opportunities or greater necessity for outdoor physical labor related to rural occupations (e.g. farming) or property maintenance (e.g. brush clearance). However, another result suggests that density is not the only facet of urban form that matters: one of our two models finds a significant reduction in BMI for subjects living within 1 km of a designated downtown core. While density is higher than average in these cores, it may be other design characteristics associated with walkable neighborhoods—such as mix of uses, pedestrian infrastructure, and difficulty in parking—that make them more walkable, leading to lower BMI for nearby residents.
  Authors: Troy, Austin; LIttenberg, Benjamin
  Authors: Troy, Austin; LIttenberg, Benjamin
  Year: 2013
  Document Type: Paper
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-4027
• A Survey of Hospital Travel Plans in England
  Abstract: The negative externalities of high rates of car use associated with the National Health Service (NHS) have been a major policy concern in the UK. Every healthcare authority was required to produce a travel plan by December 2010, with a higher emphasis on promoting walking and cycling as a means of accessing hospitals. Evidence shows that although the take-up of travel plans is increasing across the NHS, the impact of travel plans in promoting walking as a travel option is relatively low among hospital staff. There is a lack of research on hospital travel plans, specifically in terms of what factors may have affected their success. This empirical study aims at bridging the gap between research and practice by capturing the views of the NHS representatives on hospital travel plans through a questionnaire. The survey findings show that despite having a high potential to promote walking as a key travel option among the hospital staff, the measures to promote walking were cited as the least effective. A Spearman correlation coefficient test was performed to evaluate the correlation between travel plan measures to promote walking and restrictive measures to reduce the use of cars. The results show that the effectiveness of measures to reduce the use of cars is positively correlated with the effectiveness of measures to promote walking. The effectiveness of travel plan measures is attributed to the successful adoption of innovative organisational practices and strategies in the dynamic situational and individual travel context.
  Authors: Khandokar, Fahmida; Ryley, Tim; Ison, Stephen; Price, Andrew
  Authors: Khandokar, Fahmida; Ryley, Tim; Ison, Stephen; Price, Andrew
  Year: 2013
  Document Type: Paper
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-4450
• Commute Well-being Among Bicycle, Transit, and Car Users in Portland, Oregon
  Abstract: To understand the impact of daily travel on personal and societal well-being, measurement techniques that go beyond satisfaction-based measures of travel are used. Such metrics are increasingly important for evaluating transportation and land-use policies. This study examines commute well-being, a multi-item measure of how one feels about the commute to work, and its influences using data from a web-based survey that was distributed to Portland, Oregon, U.S.A. workers. Valid surveys (n=828) were compiled from three roughly equally sized groups based on mode: bike, transit and car users. Average distances between work and home varied significantly among the three groups. Descriptive results show that commute well-being varies widely across the sample. Those who bike to work have significantly higher commute well-being than transit and car commuters. A multiple linear regression model shows that along with travel mode, traffic congestion, travel time, income, health, job satisfaction and residential satisfaction also play important individual roles in shaping commute well-being. While more analysis is needed, these results support findings in previous research that commuting by bike enhances well-being while congestion detracts from well-being. Implications for future research and sustainable transportation policy efforts are discussed.
  Authors: Smith, Oliver
  Authors: Smith, Oliver
  Year: 2013
  Document Type: Paper
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-4479
• Smart Growth, Environmental Justice, and Projected Cancer Risk in Southern California: Case Study in Regional Planning and Health
  Abstract: As cities and regions are working towards sustainability by enhancing transit infrastructure and increasing population and employment in targeted neighborhoods, a question arises if greater density in urban areas will increase the exposure of cancer risk to a larger number of people, especially in areas that are in close proximity to highly traveled corridors. Since urban areas have traditionally held a higher share of racial and ethnic minority groups than suburban and outlying areas, this paper will specifically examine the implications of “smart growth” land use and transportation strategies for the public health of various population groups. The recent 2012-2035 Regional Transportation Plan and Sustainable Communities Strategy (RTP/SCS) adopted by the Southern California Association of Governments (SCAG) serves as a case study to examine the projected cancer risks in Southern California attributed to this Plan. Geographic Weighted Regression (GWR) is used to determine future health risk based upon current and projected emissions outputs associated with on-road vehicles. This study shows that increased transit infrastructure and targeted growth in population density reduces the amount of disproportionate impacts for certain racial and ethnic minority groups associated with cancer risk in future years. Alternatively, the number of persons exposed to higher cancer risk areas is greater in future years as a result of these such strategies.
  Authors: Clark, Kimberly Martin; Wen, Frank; Choi, Simon; Hu, Hsi-hwa
  Authors: Clark, Kimberly Martin; Wen, Frank; Choi, Simon; Hu, Hsi-hwa
  Year: 2013
  Document Type: Paper
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-5324
• Modeling Frequency and Duration of Out-of-Home Physical Activity Participation of School-Going Children
  Abstract: This paper investigates the frequency and duration of physical activity participation of school-going children in Dhaka City, Bangladesh. The study uses an activity-based travel diary survey dataset, collected in 2012, which contains 245 students from grades 6 to 10 in the Dhaka Metropolitan Area. In order to explore tradeoffs among factors that affect frequency of out-of-home physical activity including the use of active transportation this paper utilizes a Zero-inflated Poisson regression (ZIP) model. Additionally, parametric hazard models are estimated to examine the duration of physical activities. The results of the ZIP count model suggest that personal and household characteristics, built environment attributes, and time commitments for other mandatory and discretionary activities influence the frequency of participation. For example, an increase in the number of children in households, and the presence of sidewalks, increase the frequency of out-of home out-of-school physical activities if everything else held equal. In contrast, travel time to school, presence of traffic intersections, and time commitment for tutoring sessions negatively affect activity participation. In terms of modeling duration of out-of-home physical activities, this study finds that a Weibull parametric hazard model outperforms a log-logistic model. The duration is influenced by socio-demographic characteristics, spatial context, and escort arrangements. For instance, car ownership and parental escorting increase the duration of physical activity. The paper offers an in-depth behavioral understanding of children’s physical activities, particularly in the context of a developing country, which is very limited in the existing literature.
  Authors: Habib, Muhammad Ahsanul; Daisy, Naznin Sultana
  Authors: Habib, Muhammad Ahsanul; Daisy, Naznin Sultana
  Year: 2013
  Document Type: Paper
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-5356
• Using Urban Commuting Data to Calculate a Spatiotemporal Accessibility Measure for Healthy Food Environment Studies
  Authors: Widener, Michael
  Authors: Widener, Michael
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-0825
• School Commute Air Quality: Understanding Variation in Pollutant Exposure for Students Traveling to School by Auto, Bus, or Walking
  Authors: Moore, Adam
  Authors: Moore, Adam
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-3315
• Analysis of School Trip Mode Choice: Promoting Active Travel
  Authors: Ermagun, Alireza
  Authors: Ermagun, Alireza
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-3618
• Commute Well-being Among Bicycle, Transit, and Car Users in Portland, Oregon
  Authors: Smith, Oliver
  Authors: Smith, Oliver
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-4479
• Smart Growth, Environmental Justice, and Projected Cancer Risk in Southern California: Case Study in Regional Planning and Health
  Authors: Clark, Kimberly
  Authors: Clark, Kimberly
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-5324
• Modeling Frequency and Duration of Out-of-Home Physical Activity Participation of School-Going Children
  Authors: Daisy, Naznin
  Authors: Daisy, Naznin
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-5356
• A Survey of Hospital Travel Plans in England
  Authors: Khandokar, Fahmida
  Authors: Khandokar, Fahmida
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Pedestrians and Bicyclists; Policy; Society
  Session: 351
  Paper Number: 13-4450