Journal of Physical Activity and Health, 2015, 12, 483 -489 http://dx.doi.org/10.1123/jpah.2013-0342 © 2015 Human Kinetics, Inc.
ORIGINAL RESEARCH
Transit-Related Walking to Work in Promoting Physical Activity Chia-Yuan Yu and Hsien-Chang Lin Background: Transit-related walking to work is a potential strategy for incorporating physical activity into daily life and promoting health benefits. This study estimated the transit-related walking time for work trips on the journey to and from work and examined the predictors of transit users who walked to/from transit and the workplace and those who walked 30 minutes or more per day. Methods: This study used the 2009 National Household Travel Survey and identified 772 subjects who took transit to/from work, 355 subjects who walked to/from transit and the workplace, and 145 subjects who walked 30 minutes or more per day among the 40,659 workers. Weighted logistic regressions were used for the analysis. Results: Of the people who walked to/from transit and the workplace, 40.9% walked 30 minutes or more per day. The weighted logistic regressions revealed that low-income groups and workers living in high population density areas were more likely to walk to/from transit and the workplace. Workers living in high population density areas were more likely to walk 30 minutes or more per day. Conclusions: Transit-related walking to work provides an opportunity to increase physical activity levels and to meet the physical activity recommendations. Keywords: work trips, exercise, commuting
Regular physical activity provides important health benefits such as the prevention of obesity,1,2 cardiovascular disease,3,4 and mental health disorders.5,6 The U.S. Department of Health and Human Services has developed a guideline for the recommended level of physical activity. Based on the 2008 Physical Activity Guidelines for Americans, adults who engage in at least 150 minutes of moderate-intensity aerobic, activity such as brisk walking, per week are more likely to obtain greater health benefits than individuals who do not engage in physical activity. However, only 64.5% of Americans are physically active.7 Transit is considered as the transportation modes that carry people from one place to another, such as buses, trains, or ferries. The use of transit could be a potential source of physical activity due to the opportunity to walk/bike from the trip origin to transit and from transit to the trip destination,8,9 and the habitual walking of transit users is associated with higher amounts of physical activity.10 For example, a study used the 2001 National Household Travel Survey (NHTS) and found that 29% of transit users achieved the recommended level of physical activity by walking to/from transit.10 Another study estimated the change in the number of transit walkers from 2001 to 2009 in the United States and found that there was a 31% increase in walkers who reached 30 minutes or more of physical activity.11 However, these studies considered only all trip purposes (eg, commuting to work, shopping, school or church activities, social or recreational activities, etc), which included both regular trips (repeated trips at fixed times and locations, such as commuting to work) and recreational trips (trips at flexible times and locations, such as commuting to shopping). Workers have to travel to/from
work every day and these travels have been identified as an opportunity to accumulate levels of physical activity10–13; therefore, it is important to separate the effects of regular and recreational trips. Active travel to work has been demonstrated as a means of integrating physical activity into daily life and producing positive health outcomes.10–13 For example, Lindstrom11 asserted that people who walked, biked, or took transit to work were less likely to be overweight or obese. However, these studies examined the relationship between the use of a primary travel mode to work and physical activity, an approach which ignored the importance of multiple travel modes and their connections. Moreover, little attention has been devoted to examining work trips between home and the workplace and their relationship to physical activity.14 Therefore, transit-related walking to work, a behavior that could provide substantial potential health benefits, requires scholarly attention, especially with regards to its influence on physical activity. Unlike previous studies that examined either the means of transportation to/from work or the travel mode to/from transit, this study focused on the journey to work (from home to transit and transit to the workplace) and the journey from work (from the workplace to transit and transit to home). The purpose of this study was to assess how many transit users walked to/from transit and the workplace and the percentage of users who reached the recommended levels of physical activity by walking to/from transit and the workplace. Moreover, this study examined the sociodemographic characteristics of transit walkers and those who achieved 30 minutes or more of physical activity per day.
Methods Yu ([email protected]) is with the School of Public Administration, University of Central Florida, Orlando, FL. Lin is with the Dept of Applied Health Science, School of Public Health, Indiana University, Bloomington, IN.
Study Population This study used the 2009 NHTS, which was conducted by the U.S. Department of Transportation,15 to estimate the mean time spent 483
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484 Yu and Lin
walking to/from transit and the workplace. NHTS was a telephone survey that used random digital dialing of a sample of landline numbers through computer-assisted telephone interviewing technology.16 NHTS targeted the civilian, noninstitutionalized population in the United States. People aged 18 or older in households with a valid address through their telephone numbers were included. Individuals living in medical institutions, prisons, and in barracks on military bases were excluded. Moreover, NHTS excluded individuals living in rooms with more than 10 people who shared the same telephone number such as dormitory rooms and fraternity and sorority houses.16 These selected households were first invited to participate in the telephone interview via advance letters (including letters from the NHTS program manager, introductory brochures, and $5 cash incentives); these letters were followed by a telephone call 1 week later.16 Households who completed the interview then were sent a travel diary to collect detailed travel-related information for the assigned travel date. This travel date was randomly assigned by the computerassisted telephone interviewing program to each household for all 7 days of the week, including all holidays. The mailed travel diary collected the information including the purpose for each trip (eg, home, work, shopping, school, meals, medical services, etc), whether the trip was home-based (either the trip origin or the trip destination was home; eg, home-based work, home-based social/ recreational, home-based shopping, other home-based, and not home-based), the mode of transportation used for each trip (eg, car, bus, walk, etc), and the estimated time from the trip origin to the destination for each trip in the assigned 24-hour travel day starting at 4:00 AM and continuing until 3:59 AM of the following day. Moreover, for those who used transit as the travel mode for the trip, this travel diary also asked the mode they used to get to transit (eg, car, motorcycle, bicycle, walk, taxicab, bus, etc).16 The telephone interview collected sociodemographic information such as race, gender, education level, household income, households with or without children, respondent’s age, number of vehicles, and worker status for every family member. The NHTS also asked respondents where they lived to estimate population density based on census block groups.16 To consider seasonal variations in travel, interviews were conducted from March 17, 2008, through May 7, 2009. In addition, this survey used a complex sampling and weighting scheme to ensure that the data could be used to represent the national estimates. In total, 19.8% (N = 150 147) of all interviews were identified as usable households.16
Trip Selection Several steps were applied to select the transit-related walking trips between home and the workplace (Figure 1). The survey asked each respondent if they were employed. In total, 40,659 respondents answered yes and were identified as workers in this study. To identify workers who took transit to work between home and the workplace, the trips were selected if (1) the trip was homebased work, (2) the trip purposes were work for the journey to work (from home to the workplace) and home for the journey from work (from the workplace to home), and (3) the travel modes used for the trip were public transit (eg, buses, trains, or ferries). This study excluded those who went somewhere else on the way between home and transit and between transit and the workplace. In total, 772 respondents were identified as workers who took transit to work between home and the workplace.
Figure 1 — Trip selection from the 2009 National Household Travel Survey.
Among these 772 respondents, those who walked to transit for all portions of the journey to work (from home to transit and transit to the workplace) and the journey from work (from the workplace to transit and transit to home) were identified as transit and workplace walkers (N = 355). Those who only walked to transit for part of portions of the journey were not considered as transit and workplace walkers. This study also excluded respondents who did not provide the information about how they get to transit on the journey to/from work. Moreover, 74 respondents who used multiple travel access modes to transit were excluded. For instance, respondents who drove their cars to parking lots and walked to transits were not included. Among transit and workplace walkers, the total walking time was summed based on the estimated travel time for the journey to work and the journey from work. In total, 145 respondents walked 30 minutes or more per day to/from transit and the workplace.
Variables To examine sociodemographic characteristics of transit and workplace walkers, a binary dependent variable—among those who used transit to work between home and the workplace, whether they walked to transit for all portions of the journey to/from work—was generated. Furthermore, to explore sociodemographic characteristics of those who walked 30 minutes or more per day to/from transit and the workplace, another binary dependent variable—among those who walked to transit for all portions of the journey to/from work, whether they reached 30 minutes or more walking—was also created. In terms of independent variables, based on previous studies on the means of transportation to/from work and the travel mode to/
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Transit-Related Walking to Work 485
from transit,10,11,17,18 this study selected age, race, gender, education level, household income, number of vehicles in the household, and population density in the residence. Regarding households with or without children, employed adults in a household with young children made additional stops to pick up/drop off their kids.19 Thus, this study assumed that they would be less likely to take transit to work.
Downloaded by University of South Carolina on 09/16/16, Volume 12, Article Number 4
Measurements Regarding the measurements of variables, the race variable was separated into 5 groups: White, Black, Asian, Hispanic, and other (including Native American, Native Alaskan, Native Hawaiian, other Pacific, and multiracial). The respondents’ education levels were grouped into less than high school, high school, undergraduate, and graduate. Household income levels were divided into households with incomes
ORIGINAL RESEARCH
Transit-Related Walking to Work in Promoting Physical Activity Chia-Yuan Yu and Hsien-Chang Lin Background: Transit-related walking to work is a potential strategy for incorporating physical activity into daily life and promoting health benefits. This study estimated the transit-related walking time for work trips on the journey to and from work and examined the predictors of transit users who walked to/from transit and the workplace and those who walked 30 minutes or more per day. Methods: This study used the 2009 National Household Travel Survey and identified 772 subjects who took transit to/from work, 355 subjects who walked to/from transit and the workplace, and 145 subjects who walked 30 minutes or more per day among the 40,659 workers. Weighted logistic regressions were used for the analysis. Results: Of the people who walked to/from transit and the workplace, 40.9% walked 30 minutes or more per day. The weighted logistic regressions revealed that low-income groups and workers living in high population density areas were more likely to walk to/from transit and the workplace. Workers living in high population density areas were more likely to walk 30 minutes or more per day. Conclusions: Transit-related walking to work provides an opportunity to increase physical activity levels and to meet the physical activity recommendations. Keywords: work trips, exercise, commuting
Regular physical activity provides important health benefits such as the prevention of obesity,1,2 cardiovascular disease,3,4 and mental health disorders.5,6 The U.S. Department of Health and Human Services has developed a guideline for the recommended level of physical activity. Based on the 2008 Physical Activity Guidelines for Americans, adults who engage in at least 150 minutes of moderate-intensity aerobic, activity such as brisk walking, per week are more likely to obtain greater health benefits than individuals who do not engage in physical activity. However, only 64.5% of Americans are physically active.7 Transit is considered as the transportation modes that carry people from one place to another, such as buses, trains, or ferries. The use of transit could be a potential source of physical activity due to the opportunity to walk/bike from the trip origin to transit and from transit to the trip destination,8,9 and the habitual walking of transit users is associated with higher amounts of physical activity.10 For example, a study used the 2001 National Household Travel Survey (NHTS) and found that 29% of transit users achieved the recommended level of physical activity by walking to/from transit.10 Another study estimated the change in the number of transit walkers from 2001 to 2009 in the United States and found that there was a 31% increase in walkers who reached 30 minutes or more of physical activity.11 However, these studies considered only all trip purposes (eg, commuting to work, shopping, school or church activities, social or recreational activities, etc), which included both regular trips (repeated trips at fixed times and locations, such as commuting to work) and recreational trips (trips at flexible times and locations, such as commuting to shopping). Workers have to travel to/from
work every day and these travels have been identified as an opportunity to accumulate levels of physical activity10–13; therefore, it is important to separate the effects of regular and recreational trips. Active travel to work has been demonstrated as a means of integrating physical activity into daily life and producing positive health outcomes.10–13 For example, Lindstrom11 asserted that people who walked, biked, or took transit to work were less likely to be overweight or obese. However, these studies examined the relationship between the use of a primary travel mode to work and physical activity, an approach which ignored the importance of multiple travel modes and their connections. Moreover, little attention has been devoted to examining work trips between home and the workplace and their relationship to physical activity.14 Therefore, transit-related walking to work, a behavior that could provide substantial potential health benefits, requires scholarly attention, especially with regards to its influence on physical activity. Unlike previous studies that examined either the means of transportation to/from work or the travel mode to/from transit, this study focused on the journey to work (from home to transit and transit to the workplace) and the journey from work (from the workplace to transit and transit to home). The purpose of this study was to assess how many transit users walked to/from transit and the workplace and the percentage of users who reached the recommended levels of physical activity by walking to/from transit and the workplace. Moreover, this study examined the sociodemographic characteristics of transit walkers and those who achieved 30 minutes or more of physical activity per day.
Methods Yu ([email protected]) is with the School of Public Administration, University of Central Florida, Orlando, FL. Lin is with the Dept of Applied Health Science, School of Public Health, Indiana University, Bloomington, IN.
Study Population This study used the 2009 NHTS, which was conducted by the U.S. Department of Transportation,15 to estimate the mean time spent 483
Downloaded by University of South Carolina on 09/16/16, Volume 12, Article Number 4
484 Yu and Lin
walking to/from transit and the workplace. NHTS was a telephone survey that used random digital dialing of a sample of landline numbers through computer-assisted telephone interviewing technology.16 NHTS targeted the civilian, noninstitutionalized population in the United States. People aged 18 or older in households with a valid address through their telephone numbers were included. Individuals living in medical institutions, prisons, and in barracks on military bases were excluded. Moreover, NHTS excluded individuals living in rooms with more than 10 people who shared the same telephone number such as dormitory rooms and fraternity and sorority houses.16 These selected households were first invited to participate in the telephone interview via advance letters (including letters from the NHTS program manager, introductory brochures, and $5 cash incentives); these letters were followed by a telephone call 1 week later.16 Households who completed the interview then were sent a travel diary to collect detailed travel-related information for the assigned travel date. This travel date was randomly assigned by the computerassisted telephone interviewing program to each household for all 7 days of the week, including all holidays. The mailed travel diary collected the information including the purpose for each trip (eg, home, work, shopping, school, meals, medical services, etc), whether the trip was home-based (either the trip origin or the trip destination was home; eg, home-based work, home-based social/ recreational, home-based shopping, other home-based, and not home-based), the mode of transportation used for each trip (eg, car, bus, walk, etc), and the estimated time from the trip origin to the destination for each trip in the assigned 24-hour travel day starting at 4:00 AM and continuing until 3:59 AM of the following day. Moreover, for those who used transit as the travel mode for the trip, this travel diary also asked the mode they used to get to transit (eg, car, motorcycle, bicycle, walk, taxicab, bus, etc).16 The telephone interview collected sociodemographic information such as race, gender, education level, household income, households with or without children, respondent’s age, number of vehicles, and worker status for every family member. The NHTS also asked respondents where they lived to estimate population density based on census block groups.16 To consider seasonal variations in travel, interviews were conducted from March 17, 2008, through May 7, 2009. In addition, this survey used a complex sampling and weighting scheme to ensure that the data could be used to represent the national estimates. In total, 19.8% (N = 150 147) of all interviews were identified as usable households.16
Trip Selection Several steps were applied to select the transit-related walking trips between home and the workplace (Figure 1). The survey asked each respondent if they were employed. In total, 40,659 respondents answered yes and were identified as workers in this study. To identify workers who took transit to work between home and the workplace, the trips were selected if (1) the trip was homebased work, (2) the trip purposes were work for the journey to work (from home to the workplace) and home for the journey from work (from the workplace to home), and (3) the travel modes used for the trip were public transit (eg, buses, trains, or ferries). This study excluded those who went somewhere else on the way between home and transit and between transit and the workplace. In total, 772 respondents were identified as workers who took transit to work between home and the workplace.
Figure 1 — Trip selection from the 2009 National Household Travel Survey.
Among these 772 respondents, those who walked to transit for all portions of the journey to work (from home to transit and transit to the workplace) and the journey from work (from the workplace to transit and transit to home) were identified as transit and workplace walkers (N = 355). Those who only walked to transit for part of portions of the journey were not considered as transit and workplace walkers. This study also excluded respondents who did not provide the information about how they get to transit on the journey to/from work. Moreover, 74 respondents who used multiple travel access modes to transit were excluded. For instance, respondents who drove their cars to parking lots and walked to transits were not included. Among transit and workplace walkers, the total walking time was summed based on the estimated travel time for the journey to work and the journey from work. In total, 145 respondents walked 30 minutes or more per day to/from transit and the workplace.
Variables To examine sociodemographic characteristics of transit and workplace walkers, a binary dependent variable—among those who used transit to work between home and the workplace, whether they walked to transit for all portions of the journey to/from work—was generated. Furthermore, to explore sociodemographic characteristics of those who walked 30 minutes or more per day to/from transit and the workplace, another binary dependent variable—among those who walked to transit for all portions of the journey to/from work, whether they reached 30 minutes or more walking—was also created. In terms of independent variables, based on previous studies on the means of transportation to/from work and the travel mode to/
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Transit-Related Walking to Work 485
from transit,10,11,17,18 this study selected age, race, gender, education level, household income, number of vehicles in the household, and population density in the residence. Regarding households with or without children, employed adults in a household with young children made additional stops to pick up/drop off their kids.19 Thus, this study assumed that they would be less likely to take transit to work.
Downloaded by University of South Carolina on 09/16/16, Volume 12, Article Number 4
Measurements Regarding the measurements of variables, the race variable was separated into 5 groups: White, Black, Asian, Hispanic, and other (including Native American, Native Alaskan, Native Hawaiian, other Pacific, and multiracial). The respondents’ education levels were grouped into less than high school, high school, undergraduate, and graduate. Household income levels were divided into households with incomes
