Geographic regions for assessing built environmental correlates with walking trips: A comparison using different metrics and model designs

Tribby C.P., Miller H.J., Brown B.B., Smith K.R. and Werner C.M. “Geographic regions for assessing built environmental correlates with walking trips: A comparison using different metrics and model designs, Health and Place, 45, 1-9.

Highlights

  • We assess walking with audit and perceived built environment measures.
  • Spatial measures are walking activity spaces and self-defined neighborhoods.
  • Findings indicate that environmental measures have preferred spatial extents.
  • Researchers need to consider varying spatial measures to assess walking correlates

Abstract

There is growing international evidence that supportive built environments encourage active travel such as walking. An unsettled question is the role of geographic regions for analyzing the relationship between the built environment and active travel. This paper examines the geographic region question by assessing walking trip models that use two different regions: walking activity spaces and self-defined neighborhoods. We also use two types of built environment metrics, perceived and audit data, and two types of study design, cross-sectional and longitudinal, to assess these regions. We find that the built environment associations with walking are dependent on the type of metric and the type of model. Audit measures summarized within walking activity spaces better explain walking trips compared to audit measures within self-defined neighborhoods. Perceived measures summarized within self-defined neighborhoods have mixed results. Finally, results differ based on study design. This suggests that results may not be comparable among different regions, metrics and designs; researchers need to consider carefully these choices when assessing active travel correlates.

Public transit generates new physical activity

Miller HJ, Tribby CP, Brown BB, Smith KR, Werner CM, Wolf J, Wilson L, Oliveira MGS (2015) “Public transit generates new physical activity: Evidence from individual GPS and accelerometer data before and after light rail construction in a neighborhood of Salt Lake City, Utah, USA,” Health & Place, 26, 8-17. doi:10.1016/j.healthplace.2015.08.005

Highlights

  • We track physical activity time before and after construction of a light rail line
  • Study participants wore accelerometers and GPS recorders
  • Changes in physical activity time relate directly to changes in transit use
  • No substitution of transit-related physical activity time for other activity time

Abstract: Poor health outcomes from insufficient physical activity (PA) are a persistent public health issue. Public transit is often promoted for positive influence on PA. Although there is cross-sectional evidence that transit users have higher PA levels, this may be coincidental or shifted from activities such as recreational walking. We use a quasi-experimental design to test if light rail transit (LRT) generated new PA in a neighborhood of Salt Lake City, Utah, USA. Participants (n=536) wore Global Positioning System (GPS) receivers and accelerometers before (2012) and after (2013) LRT construction. We test within-person differences in individuals’ PA time based on changes in transit usage pre- versus post-intervention. We map transit-related PA to detect spatial clustering of PA around the new transit stops. We analyze within-person differences in PA time based on daily transit use and estimate the effect of daily transit use on PA time controlling for socio-demographic variables. Results suggest that transit use directly generates new PA that is not shifted from other PA. This supports the public health benefits from new high quality public transit such as LRT.

Assessing built environment walkability using activity-space summary measures

Tribby, C.P., Miller, H.J., Brown, B.B., Werner, C.M., & Smith, K.R. (2015). Assessing built environment walkability using activity-space summary measures. Journal Of Transport and Land Use. [Article in Press scheduled for vol. 9 (2016) issue 1 pp. 1–21]  doi: http://dx.doi.org/10.5198/jtlu.2015.625

There is increasing emphasis in fields such as transportation planning and public health on walking as a sustainable form of mobility and a means of achieving recommended physical activity for better health outcomes. A key question is measuring the influence of the built environment on walking to determine environmental modifications that enhance walkability.  However, it is unclear how to aggregate georeferenced walkability measures to geographic units that are meaningful for behavioral analysis.  This paper develops methods for assessing walkability within individual activity spaces: the geographic region accessible to an individual during a given walking trip. Based on objective walkability measures of the street blocks, we use three summary measures for walkability within activity spaces: i) the average walkability score across block segments, ii) the standard deviation, and iii) the network autocorrelation. We assess the method using data from an empirical study of built environment walkability and walking behavior in Salt Lake City, Utah. We visualize these activity-space summary measures to compare walkability among individuals’ trips within their neighborhoods. We also compare summary measures for activity spaces versus Census block groups.

Keywords: Walkability, activity spaces, built environment