title: The Effect of Light Rail Transit on Physical Activity: Design and Methods of the Travel-Related Activity in Neighborhoods Study.
abstract: BACKGROUND
  Use of mass transit has been proposed as a way to incorporate regular physical activity into daily life because transit use typically requires additional travel to access and depart the stop or station. If this additional travel is active, a small but potentially important amount of physical activity can be achieved daily. Although prior research has shown that transit use is associated with physical activity, important questions remain unanswered. Utilizing a major expansion of the Houston, TX, USA light-rail system as a natural experiment, the Houston Travel-Related Activity in Neighborhoods (TRAIN) Study was developed to address these unanswered questions.
  
  
  OBJECTIVE
  The purpose of the TRAIN Study is to determine if the development of light-rail lines in Houston, TX, USA will prospectively affect both transit use and physical activity over 4 years. We also aim to understand how contextual effects (i.e., moderators or interaction effects), such as the neighborhood built environment and socioeconomic factors, affect the primary relations under study.
  
  
  METHODS
  The TRAIN Study is a longitudinal cohort design, in which participants are recruited at baseline from a 3-mile buffer around each of the three new lines and measured annually four times. Recruitment is accomplished via telephone contact, ads in newspapers and advertising circulars, and targeted community outreach. Data are collected via mail and include questionnaire-assessed factors, such as perceived neighborhood characteristics, attitudes about transportation, demographics, and reported physical activity; a travel diary; and accelerometry. Additionally, field-based neighborhood audits are conducted to capture micro-scale environmental features. To assess macro-scale environmental characteristics, we utilize GIS mapping and spatial analyses. Statistical analyses will be conducted using latent growth curve modeling and discrete choice models, with a focus on identifying moderating factors (i.e., statistical interaction effects). Selection bias will be controlled via propensity score analysis.
  
  
  CONCLUSIONS
  The TRAIN study is a unique opportunity to study how a multi-billion dollar investment in mass transit can simultaneously affect transportation needs and physical activity behavior. This comprehensive evaluation will provide needed evidence for policy makers, and can inform health impact assessments of future transportation projects around the world.
authors.affiliation: Department of Health Promotion and Behavioral Science, University of Texas Health Science Center at Houston School of Public Health, Houston, TX, USA; Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA.
authors.forename: Casey P
authors.initials: CP
authors.lastname: Durand
authors.affiliation: Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health , Austin, TX , USA.
authors.forename: Abiodun O
authors.initials: AO
authors.lastname: Oluyomi
authors.affiliation: Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA; Department of Epidemiology, Human Genetics and Environmental Sciences, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA.
authors.forename: Kelley Pettee
authors.initials: KP
authors.lastname: Gabriel
authors.affiliation: Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA; The University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA; Center for Nutrition and Health Research, National Institute of Public Health of Mexico, Cuernavaca, Mexico.
authors.forename: Deborah
authors.initials: D
authors.lastname: Salvo
authors.affiliation: Texas A&M Transportation Institute , Austin, TX , USA.
authors.forename: Ipek N
authors.initials: IN
authors.lastname: Sener
authors.affiliation: Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA; Department of Health Promotion and Behavioral Science, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA.
authors.forename: Deanna M
authors.initials: DM
authors.lastname: Hoelscher
authors.affiliation: Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA; Department of Epidemiology, Human Genetics and Environmental Sciences, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Knell
authors.affiliation: Department of Health Promotion and Behavioral Science, University of Texas Health Science Center at Houston School of Public Health, Houston, TX, USA; Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Tang
authors.affiliation: Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA; Department of Epidemiology, Human Genetics and Environmental Sciences, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Porter
authors.affiliation: Department of Health Promotion and Behavioral Science, University of Texas Health Science Center at Houston School of Public Health, Houston, TX, USA; Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Robertson
authors.affiliation: Michael & Susan Dell Center for Healthy Living, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA; Department of Epidemiology, Human Genetics and Environmental Sciences, University of Texas Health Science Center at Houston School of Public Health, Austin, TX, USA; University of Texas at Austin, Austin, TX, USA.
authors.forename: Harold W
authors.initials: HW
authors.lastname: Kohl
keywords: active travel; built environment; light rail; physical activity; transit; transportation