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Environment and Planning B: Planning and Design 2015, volume 42, pages 000 – 000 doi:10.1068/b130222p Neighborhood design, neighborhood location, and three types of walking: results from the Washington DC area Gi-Hyoug Cho School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Building 106, 801-7, Ulsan, Korea 689-798; e-mail: [email protected] Daniel A Rodríguez Department of City and Regional Planning and Institute for the Environment, University of North Carolina, CB 3140 New East Building, Room 319, Chapel Hill, NC 27599, USA; e-mail: [email protected] Received 23 December 2013; in revised form 24 April 2014; published online 10 April 2015 Abstract. Understanding how the built environment at a neighborhood scale is associated with individuals’ walking has been a common research objective in public health and city planning. In contrast to the extant literature, we examine whether a neighborhood’s location defined at a regional scale is associated with walking and whether this association is separately identifiable from the association of the neighborhood built environment and walking. The findings indicated that walking for commuting purposes was associated more strongly with neighborhood location than with the neighborhood built environment, whereas walking for shopping–eating purposes had a stronger association with the neighborhood built environment. The results suggest that, without the provision of better public transportation services to suburban neighborhoods, walkable neighborhood development in suburbs may not be successful for encouraging walking for commuting. Keywords: built environment, travel behavior, walkability 1 Introduction Modifying the neighborhood built environment is recognized as a means of facilitating walking in addition to creating a positive social environment. Previous studies have provided ample empirical evidence that the neighborhood built environment plays a role in increasing walking (Ewing and Cervero, 2010; Lee and Moudon, 2004; Saelens and Handy, 2008). Walking for transportation is associated with living in neighborhoods that offer convenient access to destinations, connected street networks, and higher residential densities, whereas neighborhood aesthetics, access to parks and beaches, and quality of the pedestrian infrastructure tend to be associated with increased walking for recreation purposes (Saelens and Handy, 2008). In contrast to the neighborhood-scale environment, the regional-scale or macrolevel environment comprises to the distribution of activities and transportation facilities across a region (Handy et al, 2002). Understanding the regional-scale environment and its association with the neighborhood-scale environment is important, as the regional-scale environment is likely, in part, to determine the neighborhood-level characteristics of the built environment, including residential density, land-use mix, and street connectivity (Næss, 2005). Handy’s earlier work (1993) defined regional accessibility as the degree of access to specific regional retail centers, suburban shopping malls, or downtown commercial areas. She pointed out that considerations of regional accessibility have qualitatively different dimensions from those of local accessibility. She indicated that providing high levels of local accessibility in new developments located at the edges of a region will have a greater effect on non-work-related travel. But enhancing regional accessibility is also important in order

Neighborhood design, neighborhood location, and three types of walking: results from the Washington DC area

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Environment and Planning B: Planning and Design 2015, volume 42, pages 000 – 000

doi:10.1068/b130222p

Neighborhood design, neighborhood location, and three types of walking: results from the Washington DC area

Gi-Hyoug ChoSchool of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Building 106, 801-7, Ulsan, Korea 689-798; e-mail: [email protected] A RodríguezDepartment of City and Regional Planning and Institute for the Environment, University of North Carolina, CB 3140 New East Building, Room 319, Chapel Hill, NC 27599, USA; e-mail: [email protected] 23 December 2013; in revised form 24 April 2014; published online 10 April 2015

Abstract. Understanding how the built environment at a neighborhood scale is associated with individuals’ walking has been a common research objective in public health and city planning. In contrast to the extant literature, we examine whether a neighborhood’s location defined at a regional scale is associated with walking and whether this association is separately identifiable from the association of the neighborhood built environment and walking. The findings indicated that walking for commuting purposes was associated more strongly with neighborhood location than with the neighborhood built environment, whereas walking for shopping–eating purposes had a stronger association with the neighborhood built environment. The results suggest that, without the provision of better public transportation services to suburban neighborhoods, walkable neighborhood development in suburbs may not be successful for encouraging walking for commuting.

Keywords: built environment, travel behavior, walkability

1 IntroductionModifying the neighborhood built environment is recognized as a means of facilitating walking in addition to creating a positive social environment. Previous studies have provided ample empirical evidence that the neighborhood built environment plays a role in increasing walking (Ewing and Cervero, 2010; Lee and Moudon, 2004; Saelens and Handy, 2008). Walking for transportation is associated with living in neighborhoods that offer convenient access to destinations, connected street networks, and higher residential densities, whereas neighborhood aesthetics, access to parks and beaches, and quality of the pedestrian infrastructure tend to be associated with increased walking for recreation purposes (Saelens and Handy, 2008).

In contrast to the neighborhood-scale environment, the regional-scale or macrolevel environment comprises to the distribution of activities and transportation facilities across a region (Handy et al, 2002). Understanding the regional-scale environment and its association with the neighborhood-scale environment is important, as the regional-scale environment is likely, in part, to determine the neighborhood-level characteristics of the built environment, including residential density, land-use mix, and street connectivity (Næss, 2005).

Handy’s earlier work (1993) defined regional accessibility as the degree of access to specific regional retail centers, suburban shopping malls, or downtown commercial areas. She pointed out that considerations of regional accessibility have qualitatively different dimensions from those of local accessibility. She indicated that providing high levels of local accessibility in new developments located at the edges of a region will have a greater effect on non-work-related travel. But enhancing regional accessibility is also important in order

2 G-H Cho, D A Rodríguez

to reduce automobile travel because many required destinations may not be located within a local area.

Næss (2005) carefully explored the interrelationships between regional-scale and neighborhood-scale environments, and travel behaviors. The location of an individual’s residence close to the center of a region increases the likelihood of that individual being surrounded by a high-density and mixed-land-use neighborhood. Proximity to high-density and mixed-land-use neighborhoods results in shorter distances to job opportunities as well as to local services. Shorter distances to destinations also imply that inner-city residents may choose to walk or bike instead of using motorized transportation. Thus, residents of old and inner-city neighborhoods tend to show a higher propensity for walking (Berrigan and Troiano, 2002). Admittedly, these causal inferences over-simplify relationships between regional-scale and neighborhood-scale environments, particularly in cases where the historical urban core has lost its dominant position. However, a residence located close to the center of a region still has enormous advantages for the selection of destinations within time and budget constraints (Næss, 2005). In analytical terms, the weighted ratio of distance to destinations tends to decrease as a residential distance from the center decreases, even in a highly polycentric urban structure.

Although existing studies have examined the association between neighborhood-scale environmental features and walking, the association of the regional-scale environment with walking has rarely been explored. Only a few studies have examined the association between the regional-scale environment and travel mode, with a focus on motorized trips. Research in this area has focused on distances to a rail network (van Wee et al, 2002), to the proximity of jobs (Cervero and Duncan, 2006), or distances to downtown (Næss, 2005). Walking behaviors are commonly believed to be more influenced by the neighborhood-scale environment than by the regional-scale environment (Handy et al, 2002). The assumption behind this belief is that the influence of the neighborhood-scale environment on walking is consistent: that is, it is irrelevant whether the neighborhood is located in the downtown area or in the suburbs. We contend that this assumption should be a subject for empirical inquiry.

For this study we defined the physical characteristics of the regional-scale environment as the relative locations of neighborhoods in a region (figure 1). The aim is to compare the

Figure 1. Hypothesized relationships between planning, urban form, and individual behaviors.

Neighborhood design and location and walking types 3

influence of a neighborhood’s location defined at the regional scale and built environment characteristics defined at the neighborhood scale on the specific purpose of walking trips. The study is designed to address the following questions:

● Is walking influenced by the location of a neighborhood in a region? If so, is the association between the neighborhood’s location and walking greater than the association between characteristics of the built environment and walking? ● Do the relationships between walking, built environment characteristics, and neighborhood location change as the utilitarian purpose of walking is considered?

2 Methods2.1 Study contextThe area for this study is the Washington Metropolitan Area centered on Washington, DC. In 2009 the population of the Washington Metropolitan Area was approximately 5.5 million. The area includes the District of Columbia, two counties in Maryland, and six counties in Virginia. In addition, the area within a 20-mile radius of the edge of the metropolitan area boundary was considered in regional-dimension variables.

We used the 2009 National Household Travel Survey (NHTS version 2.0) to identify individuals’ travel pattern and residential locations. The 2009 NHTS was conducted over the period from March 2008 through May 2009. The NHTS diary required that users fill in the trip destination, trip start and arrival time, purpose of trip, mode of travel, and travel distance as open-ended questions. Respondents recorded travel behaviors for the designated 24-hour travel day starting at 4:00 AM on the day and continuing until 3:59 AM of the following day.

The residential locations of study participants were identifiable at a census block-group level, which is considered to be a neighborhood for this study. In microscopic studies, a block-group representation has limitations in identifying continuous variations between administrative demarcations (Guo and Bhat, 2007). However, it seemed the most appropriate representation of a neighborhood in this study, as the spatial scope of the study was much larger than that of a neighborhood. Furthermore, the average sizes of census block groups in the Washington Metropolitan Area was approximately 0.50 square miles which corresponds well with the concept of a walkable radius of a quarter to a half mile.

We included NHTS respondents older than 15 years of age who lived within the study area. In total 1183 participants in 698 households were selected from 516 census block groups.

2.2 Variables2.2.1 Neighborhood built environmentWe defined the neighborhood built environment as four subdimensions (table 1): density, land-use mix, street design characteristics, and proximity to parks. Density is thought to be important because higher densities tend to create a critical mass of people (Oakes et al, 2007). If a person lives in a dense area with many apartment buildings, it will be more convenient for him or her to walk to visit a neighbor than if he or she lives in a low-density area (Saelens et al, 2003). Two variables—population density and housing unit density—were selected to represent density. Figures on population and number of housing units at the census block-group level were derived from the Census 2000 database.

The second subdimension—land-use mix—implies benefits from being closer to destinations. Placing destinations within neighborhoods can produce walking trips that substitute for external vehicular trips (Cervero and Kockelman, 1997). Because land-use data at the parcel level were not available, we used employment density and retail or service job density as proxy measures of land-use mix. These measures imply the relative proximity of residences to retail facilities or services (Cervero and Duncan, 2006). The source of employment data was the Census Transportation Planning Package 2000 (CTPP), Part II.

4 G-H Cho, D A Rodríguez

As the geographical unit of the CTPP is the census-defined traffic analysis zone (TAZ), the boundaries of TAZs and census block groups are not identical. To estimate the number of jobs in each census block group, the area proportions of TAZs situated in each census block group were calculated by intersecting the TAZs with census block groups using ArcGIS 9.2. The apportioned numbers of employees were summed by each census block group.

The third subdimension—street design—characterizes the ease of moving between origins and destinations within the existing street pathway. Street connectivity is high when streets are laid out in a grid pattern and there are few barriers to direct travel between origins and destinations (Saelens et al, 2003). It is composed of road density and the ratio of three-way or four-way nodes to segments; the 2009 Topologically Integrated Geographic Encoding and Referencing (TIGER)/Line shapefiles were used for identifying street patterns. The fourth subdimension is the ratio of three-way or four-way intersections to all intersections, thought to be indicative of more connected street patterns than a higher ratio of cul-de-sacs.

Finally, park area within each census block group was calculated. Forsyth et al (2007) showed that walking for a utilitarian purpose might be decreased in low-density neighborhoods with better recreational opportunities. Thus, we hypothesized that better accessibility to local parks might be negatively associated with walking for a utilitarian purpose. The source of park data was the 2008 Tele Atlas North America. On the basis of Tele Atlas feature class codes, parklands were identified as national park or forest (D83), state park or forest (D85), or local park or recreation area (D89).

2.2.2 Neighborhood locationNeighborhood locations at a regional scale were defined as their relative locations in a region. These relative locations in a region include distances to job centers, the center of the city, metrolines, highway network, and park systems. As these measures imply relative locations of the neighborhoods, the practical meanings may not be very different from accessibility to those facilities.

Five measures were used to identify neighborhood location (table 1). First is the distance from the block group to the main core area of each metropolitan area; this is expected to be associated with the density of the neighborhood and the intensity of development. The main

Table 1. Neighborhood built environment and neighborhood location.

Dimension Variable Source

Neighborhood built environmentDensity population density Census 2000

housing unit density Census 2000Land use employment density CTPP 2000/Census 2000

retail/service job density CTPP 2000/Census 2000Street design road density Census 2000/TIGER 2009

ratio of three-way or four-way intersections

Census 2000/TIGER 2009

Park park density Tele Atlas North America 2008Neighborhood locationRegional job center regional job accessibility CTPP 2000/Census 2000

network distance from downtown TIGER 2009Regional transport system network distance to the closest DC

metrostationCensus 2000/TIGER 2009

network distance from highway Census 2000/TIGER 2009Regional park system regional park accessibility Tele Atlas North America 2008

Neighborhood design and location and walking types 5

core area in Washington Metropolitan Area was defined as Dupont Circle metrostation. The geographical center of Washington DC is Scott Circle Park, located approximately 400 m away from Dupont Circle station. There are two reasons why we chose Dupont Circle station as the center point for our study: (1) as an historic district in Northwest Washington DC, Dupont Circle was understood to be one of the landmarks in the region, and (2) accounting for the spatial range of our study area (over 20 miles radius), 400 m is a negligible scale of distance. Network analysis in ArcGIS 9.2 was used to calculate network distances from the selected core area to the center of each neighborhood.

The second measure to characterize neighborhood locations is regional job accessibility. The scope of the region for working was defined using commuting distances. Since more than 80% of commuting distances are less than 20 miles (United States Department of Transportation, 2008) in the United States, all census-defined TAZs within 20 miles of the study areas were used for calculating regional accessibility measures.

Among the various approaches used to measure accessibility, the gravity approach has been widely adopted because it provides the great advantages of being easily understood, less demanding on data, and able to show spatial variations (Baradaran and Ramjerdi, 2001). However, the gravity approach also has limitations. First, the estimation of accessibility using the gravity approach is largely dependent on the value of the distance-decay parameter, but the parameter cannot be determined with empirical data. Second, gravity measures quickly increase to infinity when the distances approach zero because the functional form relies on a negative exponential function.

As an alternative, a Gaussian function, which is widely used in statistics describing normal distributions, was used for calculating regional job accessibility. The graph of a Gaussian function is a symmetrical bell curve, and the basic functional form of Gaussian distribution is

( )x af e( )

ij cx b2ij2

2

=- -

,

wheree is Euler’s number;a is the height of the curving function;b is the position of the center of the peak;c is the width of the bell;Xij is the distance between census blocks i and j.

In calculating job accessibility, the values of a and b are set to 1 and 0, respectively, and the value of c is determined by the standard deviation of distances between census block groups and jobs. Regional job accessibility of census block i is the sum of the distance-weighted number of jobs within a region. Higher accessibility value indicates better access to jobs in a region. The primary data source that was used in this study to identify job locations was the CTPP 2000, Part II, at the TAZ level.

The third and fourth measures are the shortest network distance to a rail station and to a highway ramp. Accessibility of the neighborhood in a region depends largely on the regional transportation infrastructure, because proximity to the regional transportation infrastructure makes it easier to reach various destinations within a short amount of time. A relative distance from rail and highway networks is important in regional transportation infrastructure in order to represent the geographic locations of neighborhoods. Using network analysis in ArcGIS 9.2, the network distances from the center of each neighborhood to the closest rail station and highway ramp were calculated.

The fifth measure was regional park accessibility. Park and recreational services are essential infrastructure elements in planning (Mertes and Hall, 1995). Our calculation of this measure was based on methods proposed by Mertes and Hall (1995). First, each park

6 G-H Cho, D A Rodríguez

was classified as belonging to one of four classes according to size: neighborhood park (< 20 acres), community park (< 50 acres), large urban park (< 200 acres), and regional park (>200 acres). The service areas for these classes were 0.5 mile, 3 miles, 5 miles, and 10 miles, respectively. The level of service (LOS) of each park was defined as the size of the park divided by the population located within the service area of the park. The regional park accessibility of a neighborhood was defined as the sum of LOS of each park classification:

regional park accessibility = LOS of neighborhood parks within 0.5 mile + LOS of community parks within 3 miles + LOS of large urban parks within 5 miles + LOS of regional parks within 10 miles.

2.2.3 OutcomesOutcomes were binary: taking a walking trip (1) or not (0) on the designated 24-hour travel day. On the basis of the trip purposes, as defined in the 2009 NHTS codebook, the purpose of each walking trip was classified to one of four categories: to/from work, shopping–eating, social–entertainment, and other. Walking for social–entertainment includes trips to gym or exercising, going to the theater or sports event, visiting parks or the library, and visiting friends. Recreational walking is partially included in social–entertaining walking, but the majority of walking purposes we analyzed in this paper were utilitarian.

2.2.4 Sociodemographic characteristicsWe used five socioeconomic variables: gender, age, household size, employment, and household income. Gender (female: 1), and employment (employed: 1) were binary variables. Assuming that those younger than 60 years of age were not likely to have mobility problems caused by aging, we converted the age variable to a binary value: older or younger than 60 years of age. Household income was converted into four ordinal values: less than $30 000, $30 000–$60 000, $60 000–$100 000, and more than $100 000. Household size was converted into five ordinal values: one, two, three, four, and five or more persons.

2.3 Analytical methods2.3.1 Principal component analysis (PCA)The variables representing neighborhood location and neighborhood built environment are likely to be highly spatially correlated. Thus, it is useful to condense these variables into a smaller set in order to eliminate redundancy and correlation in the data (Song and Knaap, 2007). PCA was used to reduce strongly associated variables into a single factor for the location and built environment variables. Typically, a scale is considered reliable if its Cronbach’s a is 0.70 or higher, although Nunnally and Bernstein (1994) claimed that values greater than 0.80 are highly desirable.

Component scores for the built environment and neighborhood location were estimated using the component loadings. As the estimated component scores were standardized values with the mean centered on 0, we defined neighborhoods in highly urban (HU) locations as those having positive neighborhood location component scores, and neighborhoods in relatively less urban (LU) locations as having negative neighborhood location scores. Using the same approach, we defined highly walkable (HW) neighborhoods as those having positive built environment scores, and we defined less walkable (LW) neighborhoods as those having negative built environment scores. We then classified each neighborhood into one of four categories: highly urban–highly walkable (HUHW), highly urban–less walkable (HULW), less urban–highly walkable (LUHW), and less urban–less walkable (LULW) (table 2).

Neighborhood design and location and walking types 7

2.3.2 Binary logistic regressionAs the outcomes were binary—walked or did not walk—a binary logistic regression was the primary statistical model. On the basis of the assumption that those who live in LULW neighborhoods might be the least active group, the LULW group was designated as the reference group for each model. Using an odds ratio, we examined whether those who lived in neighborhood groups were more likely to walk for a specific purpose than those who lived in the reference group. In addition, we conducted a Wald test to examine whether the estimated odds ratio of HUHW neighborhoods to LULW neighborhoods was significantly different from the odd ratios of LUHW neighborhoods to HULW neighborhoods.

To account for the clustering of each individual within a household, we used clustered robust standard errors. Using the Bayesian information criterion (BIC) and R2-value, we compared the fits of multiple models. The BIC is a criterion for model selection with different numbers of parameters. By introducing a penalty term for the number of parameters in the model, the BIC solves the overfitting problem caused by adding an excessive number of parameters. All analyses were conducted using STATA 9.2.

3 Results3.1 Descriptive statisticsTable 3 presents the descriptive statistics. The maximum distance from the main core area indicates the spatial scope of this study. Distance was measured in miles, while regional job accessibility was represented with a relative scale. The unit of regional park accessibility was size of park per 1000 persons. In 2010 the population density of Washington, DC was 15.3 persons/acre (from Wikipedia). The average population density of the study area (12.9 persons/acre) was slightly lower than the density of the city. With respect to socioeconomic characteristics, the proportion of females was well balanced with the proportion of males. We used a relative scale for household income. On average, household income was higher than $60 000.

Table 3 shows that 33.5% of participants made one or more walking trips on the study day. Of those, 9.2% of participants walked for work, 38.0% walked for social–entertainment, and 18.8% walked for shopping–eating on the study day. The total number of participants was 1183. The numbers of participants who made trips for work, shopping–eating, and social–entertainment were 576, 527, and 510, respectively.

3.2 Principal component analysisTable 4 contains the results of the PCA. A higher location component value implies higher regional job accessibility, greater proximity to the main core area, metrostations, and highway ramps, and lower regional park accessibility. A higher local walkability component implies a more compact and mixed-use environment and a well-connected street pattern in the neighborhood but lower access to local parks. The Cronbach’s as of the variables representing urban location and the variables representing local walkability were 0.907 and 0.854, respectively.

The numbers of participants who lived in HUHW, HULW, LUHW, and LULW neighborhoods were 476 (40.2%), 137 (11.6%), 132 (11.2%), and 43 (37.0%), respectively

Table 2. Classifications of neighborhoods by location and walkability.

Built environment component score

Neighborhood location component score

positive negative

Positive highly urban–highly walkable (HUHW) less urban–highly walkable (LUHW)Negative highly urban–less walkable (HULW) less urban–less walkable (LULW)

8 G-H Cho, D A Rodríguez

(table 5). Not surprisingly, HW neighborhoods were more likely to be located close to the main core area (figure 2), but some of the HW neighborhoods were found in LU locations. Likewise, not all LW neighborhoods were located in LU locations.

3.3 Associations between location, built environment, and walkingTable 6 shows that survey respondents who lived in HUHW and HULW neighborhoods were more likely to walk than those who lived in LULW neighborhoods. Although it was not significant at the 95% confidence level, residency in an LUHW neighborhood had a marginally positive association with walking. A Wald test indicated that those who lived in LUHW (|² = 4.52) and HULW (|² = 5.10) neighborhoods were less likely to walk than those who lived in HUHW neighborhoods. Figure 3 shows the odds ratios for the four groups. Residing in a walkable local environment or living in an HU location was positively associated with walking. If individuals lived in neighborhoods having both HW and HU characteristics, the probability of walking relative to not walking was even higher. The relative odds of walking for the four groups were as follows: LULW < LUHW = HULW < HUHW.

With regard to work trips, those who lived in HUHW or HULW neighborhoods were more likely to walk than those who lived in LULW neighborhoods. However, we could not find evidence indicating that the residents of LUHW neighborhoods walked more to/from work

Table 3. Descriptive statistics for sociodemographic characteristics, outcomes, and environmental exposures (n = 1183).

Variable Unit Mean Standard deviation

Minimum Maximum

Neighborhood locationRegional job accessibility relative scale 43.1 28.7 2.6 90.9Distance from the main core area miles 11.5 7.3 1.0 34.8Distance from rail stations miles 4.3 4.5 0.0 26.4Distance from highway miles 3.1 3.5 0.1 21.5Regional park accessibility acres/1000 people 23.7 12.7 10.1 94.5Neighborhood built environmentPopulation density person/acre 12.9 14.6 0.3 114.5Household density unit/acre 6.0 8.1 0.1 67.0Employment density jobs/acre 4.7 11.5 0.0 128.5Retail service job density jobs/acre 3.0 7.4 0.0 80.5Road density feet/acre 171.5 75.0 33.1 405.9Ratio of three-way and four-way intersections

% 79.1 14.0 52.6 100.0

Park area acre 8.4 18.6 0.0 149.5Sociodemographic characteristicsFemale % 53.8 49.9Age older than 60 years % 31.7 46.6Employed % 64.7 47.8Household size relative scale 2.7 1.2 1.0 5.0Household income relative scale 3.1 1.1 1.0 4.0OutcomeWalked for any purpose % 33.5 47.2

for to or from work % 9.2 28.9for social–entertainment % 38.0 48.6for shopping–eating % 18.8 39.1

Neighborhood design and location and walking types 9

than the residents of LULW neighborhoods. A Wald test indicated that those who lived in LUHW neighborhoods walked to/from work less than the residents of HUHW neighborhoods (|² = 5.79). The odds of walking to/from work for the HUHW and HULW groups were not significantly different (|² = 1.92). In other words, living in a walkable neighborhood was not associated with the odds of walking to/from work. In terms of work-specific purposes, neighborhood location was more strongly associated with walking than the neighborhood built environment.

Analyses for walking to shopping–eating activities showed a different pattern. The residents of HUHW and LUHW neighborhoods were more likely to walk for shopping–eating purposes than the residents of LULW neighborhoods. No significant difference was found between the residents of HULW and LULW neighborhoods in this regard. The odds of walking for shopping–eating for the HUHW and LUHW groups were not significantly different (|² = 1.80) relative to the odds of not walking for this purpose. Living in a walkable neighborhood may encourage walking for shopping–eating, but residential location defined on a regional scale may have only a limited effect on walking.

For social–entertainment walking, we found that the residents of HUHW, HULW, and LUHW neighborhoods walked more than residents of LULW neighborhoods. The odds of walking for social–entertainment for the HUHW group were not significantly different from those for the HULW (|² = 0.06) or LUHW (|² = 0.12) groups. Thus, either living in a HW or HU neighborhood may encourage walking for social–entertainment. In contrast to the results

Table 4. Principal component analysis for urban location and local walkability components.

Variable Component loading

Urban LocationRegional job accessibility 0.475Network distance to the main core area −0.509Network distance to rail stations −0.481Network distance to highway ramps −0.396Regional park accessibility −0.357Cronbach a 0.907

Local WalkabilityPopulation density 0.435Household density 0.450Employment density 0.344Retail or service job density 0.351Road density 0.409Connectivity of segments 0.379Local park area −0.237Cronbach a 0.854

Table 5. Neighborhood classification (total number of neighborhoods = 516, total number of participants = 1183).

Walkable neighborhood Auto-oriented neighborhood

number of neighborhoods

number of participants

number of neighborhoods

number of participants

Highly urban 239 476 51 137Less urban 62 132 164 438

10 G-H Cho, D A Rodríguez

Figure 2. Built environment scores of the selected neighborhoods.

Low walkability

High walkability

Study areamiles

Built environment factor

0 3 6 12 18 24

Figure 3. Odds ratio and 95% confidence interval of walking in highly urban–highly walkable, highly urban–less walkable, and less urban–highly walkable neighborhoods (reference group: less urban–less walkable neighborhoods).

100

10

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0.1

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Neighborhood design and location and walking types 11

Tabl

e 6.

Adj

uste

d od

ds ra

tio (O

R) o

f wal

king

by

purp

ose

asso

ciat

ed w

ith n

eigh

borh

ood

loca

tion

and

loca

l wal

kabi

lity.

All

trips

(n =

118

3)W

ork

(n =

576

)Sh

oppi

ng–e

atin

g (n

= 5

27)

Soci

al–e

nter

tain

men

t (n

= 5

10)

95%

con

fiden

ce

inte

rval

95%

con

fiden

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inte

rval

95%

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inte

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95%

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OR

low

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OR

low

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per

OR

low

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per

OR

low

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Hig

hly

urba

n–hi

ghly

wal

kabl

e3.

102.

264.

276.

332.

7114

.79

4.10

2.07

8.13

2.00

1.24

3.11

Hig

hly

urba

n–le

ss w

alka

ble

1.78

1.04

3.04

3.29

1.16

9.33

1.17

0.26

5.26

2.25

1.15

3.92

Less

urb

an–h

ighl

y w

alka

ble

1.70

0.99

2.93

1.08

0.22

5.22

2.99

1.08

9.24

2.39

1.01

5.07

Less

urb

an–l

ess w

alka

ble

(ref

eren

ce)

Fem

ale

(dum

my)

0.88

0.69

1.13

0.99

0.55

1.78

0.97

0.61

1.56

0.80

0.55

1.16

Hou

seho

ld si

ze0.

910.

811.

031.

140.

871.

510.

790.

630.

990.

860.

731.

02A

ge >

60

year

s (du

mm

y)0.

720.

521.

002.

671.

355.

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12 G-H Cho, D A Rodríguez

for total walking, we did not find that individuals living in HW and HU neighborhoods walked more for social-entertainment than those living in neighborhoods having either HW or HU characteristics.

4 DiscussionThe findings regarding total walking trips conform to our hypothesis. A neighborhood’s location, defined on a regional scale, was associated with walking, and this association was separately identifiable from the association between the neighborhood built environment and walking. Even when the residential neighborhood had LW characteristics, residents in HU locations walked more than residents in LULW neighborhoods. The walkability of a neighborhood also had a separately identifiable association with walking.

The findings show that the relationship between the built environment and walking for work is different from the relationship between the built environment and walking for shopping–eating. Residents of walkable neighborhoods took more walking trips to/from work only when the neighborhood was located close to the main core area or regional job centers. It is noteworthy that even residents of walkable neighborhoods rarely had jobs within a walkable distance from home (ie, a quarter to half mile from their residence). A more common pattern of work trips involved the combination of walking and other modes of travel, such as bus or rail. Most of the public transportation networks are designed to serve areas close to downtown or regional job centers. Therefore, those who live farther from such areas may have fairly limited access to the public transportation system and therefore tend to give up walking as a mode of travel to/from work even when their residential neighborhoods have walkable characteristics.

In contrast to our findings, existing literature has reported an association between local built environment characteristics and walking to work (Badland et al, 2008; Owen et al, 2007; Suminski et al, 2005). We speculate that some of those findings may be partly explained by relatively high covariance between the local built environment and neighborhood location. In our study area, approximately 75% of walkable neighborhoods were located close to the main core area. Only 25% of walkable neighborhoods were located in LU areas. Without a clear distinction between a neighborhood’s location and built environment factors, it may be difficult to identify the true environmental correlates of walking to work.

The results of walking for shopping–eating revealed a different pattern. Living in neighborhoods with dense, mixed land use and well-connected street characteristics increases the chances of walking for shopping–eating. The walkable characteristics of neighborhoods reduce the average distance from home to destinations. A shorter distance between home and destinations increases the chance of selecting walking as a travel mode. However, neighborhood location defined at the regional scale was not associated with walking for shopping–eating.

Næss’s (2005) and Vilhelmson’s (1999) theoretical work may provide additional insight regarding the distinctive aspects of walking trips for work and shopping–eating. On the basis of Vilhelmson’s definition, trips to work tend to be ‘bounded trips’ where both time and geographical location are fixed. Meanwhile, shopping trips are ‘nonbounded’ or ‘semibounded trips’ where the time of the activity is flexible and the location may vary. For some nonbounded trips, people tend to choose the closest destination or a destination located outside the region. In contrast, patterns of bounded trips are to a much higher extent affected by the spatial distribution of facilities. Thus, urban structures or regional-scale environments are expected to have a stronger influence on bounded trips than on nonbounded trips (Næss, 2005).

In the literature, a typical classification of walking by purpose is either utilitarian or recreational walking (Forsyth et al, 2007; Lee, 2007; Rodríguez et al, 2006), whereas

Neighborhood design and location and walking types 13

we examined three specific purposes of walking: to/from work, shopping–eating, or social–entertainment. Notably, the purpose of walking classified in this study is a refined type of utilitarian walking, rather than a classification based on new criteria. Although a limited number of recreational walking trips might be included in walking for social–entertainment, the majority of the walking trips we examined were walking trips for utilitarian purposes. Both walking trips to/from work and trips for shopping–eating are specific types of walking trips for utilitarian purposes, but this study found that the environmental correlates of walking trips to/from work showed a different pattern from environmental correlates of walking trips for shopping–eating and environment exposures. Thus, the results underscore the importance of developing a refined conceptual model in examining the association between walking and urban form. An investigation that is sensitive to the specific purpose of walking may be desirable in the effort to understand the association between walking and urban form.

This study has certain limitations. Among recent studies (Cho et al, 2011; Forsyth et al, 2007; Rodríguez et al, 2008), it has been common practice to use a seven-day travel diary to identify individuals’ travel patterns and to detect the difference between weekend and weekday travel patterns. However, since NHTS 2009 data provide information only on one-day travel patterns, we used a relatively crude classification for outcomes: walked or not walked. For this same reason, we could not use other important characteristics of walking trips, such as frequency or duration. However, living in high-density areas may reduce the total duration or length of walking trips since the distances between origin and destination are likely to be short (Xu et al, 2010). Furthermore, because the distributions of the duration or frequency of walking trips are often highly positively skewed (Forsyth et al, 2007), appropriate outcome variables to be used in the analyses were limited.

We found that neighborhood location was positively associated with walking for work purposes but was not associated with walking for shopping–eating purposes. However, as we used data only from the Washington Metropolitan Area, the existence of similar patterns in other cities could not be confirmed. A further complexity is that the classification of neighborhood locations into categories of HU location or LU location is dependent upon a regional context. A further investigation is needed to determine if this study can be extrapolated to multiple regions; if so, such a consistency of results would enhance the external validity of the findings.

The findings of our study would have several policy implications. First, the development of walkable neighborhoods may not be successful in encouraging walking trips to/from work without the provision of a proper level of access to the public transit system connecting regional job centers. There are many benefits of well-connected street patterns reducing commuting by automobile; these benefits may be diminished when communities are situated in spatially disconnected suburban locations (Cervero and Gorham, 1995). Second, policies directed towards balancing the number of jobs and housing at a local level need to be reevaluated from a regional perspective. The policy assumption that workers will opt to live closer to their workplaces is questionable (Downs, 1992; Levine, 1998). This is because the motivation for living in highly mixed and dense neighborhoods can involve the proximity to local shopping and socializing opportunities rather than proximity to jobs. Weitz (2003) argued that adopting policies of jobs–housing balance in comprehensive plans, integrating jobs–housing balance into land-use regulations, and ensuring qualitative balance in large-scale development can be effective planning strategies for achieving a ‘true’ jobs–housing balance.

A neighborhood with walkable characteristics (ie, dense, highly mixed land use and well-connected streets) may be utilized not only by its residents, but also by individuals living outside the neighborhood. If a walkable neighborhood has weak connections with other nearby neighborhoods, the unbalanced distribution of jobs, retail facilities, and services in urban areas may discourage walking trips to access the walkable neighborhood from other

14 G-H Cho, D A Rodríguez

neighborhoods. The net effect of a walkable neighborhood in a region is an important subject for policy evaluation. While the polycentric structure of cities may increase the number of jobs in suburban areas, the growing number of multiworker households can make the true balance between jobs and housing in the same neighborhood difficult. Current efforts to encourage more infill development may increase the net effect of a walkable neighborhood in a region.

In this study we examined the relationship between the neighborhood built environ-ment, neighborhood location, and walking for various purposes. The results indicated that the association of neighborhood location with walking was separately identifiable from the association of the neighborhood built environment with walking. Living close to job centers and the regional transportation system increased the likelihood of walking to/from work. Living in walkable neighborhoods was positively associated with walking for shopping–eating. For social–entertainment, both neighborhood location and the built environment were associated with the likelihood of walking.

Aknowledgements. Preparation of this paper was supported by a grant from the Robert Wood Johnson Foundation Active Living Research program (Grant #049862).

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