Objectively assessing walkability of local communities:

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1 Objectively assessing walkability of local communities: using GIS to identify relevant environmental variables Evie Leslie, Ester Cerin, Lorinne du Toit, Neville Owen, Adrian Bauman Thanks to the Cancer Prevention Research Centre in the School of Population Health, University of Queensland and the National Centre for Social Applications of GIS (GISCA) at the University of Adelaide

2 A message from the World Health Organization (2002) Physical inactivity is a significant common and preventable risk factor for chronic NCDs Colon cancer: risk by up to 50% CVD (1/3 of all deaths): risk by up to 50% Type II diabetes: risk by up to 50% Hypertension (1/5 of population): risk Helps build/maintain healthy bones, muscles and joints Osteoporosis: risk by up to 50% in women Helps prevent and control risky behaviours Promotes psychological well-being Obesity: risk by up to 50%

3 Ecological Models of Physical Activity Environmental factors Individual factors Social factors

4 Assessing the Walkability of a Community Where do you start from? Research problem Theory Where do you aim to get to? Identifying environmental determinants What are some of the main steps along the way? Using Geographic Information Systems Field validation and assessing perceptions of environmental attributes

5 Community Environments, Transportation Factors and Physical Activity higher population density greater connectedness of streets more land use mix all associated with higher rates of walking and bicycle trips for transport relationships persist after matching communities on socioeconomic and other factors Saelens BE, Sallis, Frank (2003). Environmental correlates of walking and cycling: Findings from the transportation, urban design, and planning literatures. Annals of Behavioral Medicine, 25,

6 Based on a concept of Walkability dwelling density: the ratio of the number of dwelling units to the land area in residential use intersection density: the ratio of the number of true intersections to the land area net retail area: the average ratio of the retail gross floor space to the land area land use mix: the degree to which different land uses are scattered within the land area Frank et al, Journal American Planning Association.

7 Dwelling Density: Relationships With Walking High-density neighbourhoods include mixed-use development improves accessibility to variety of complementary activities and thus, increased utility Associated with increases in retail and service variety, resulting in shorter, walkable distances between complementary shops and restaurants Driving and parking more difficult and time consuming

8 Dwelling Density: Measurement the ratio of the number of dwelling units to the land area in residential use GIS databases to identify the attribute: Dwellings data e.g. from land registry, digital cadastral and/or other dwelling census data Boundary data for land area (parcels, CDs, study area)

9 Dwelling Data

10 Street Connectivity: Relationships With Walking Higher intersection densities are correlated with increased network connectivity, thus providing people with a greater variety of potential routes Higher connectivity provides easier access to major roads where public transport is available Shorter times to get to destinations

11 Street Connectivity: Measurement Ratio of the number of true intersections to the land area GIS databases to identify the attribute: Road centre line and intersections data

12 Patterns Of Connectivity Connected Network buffer Disconnected Sample household Crow-fly buffer Adapted from Frank LD, Engelke, Schmid (2003). Health and Community Design: The Impact of the Built Environment on Physical Activity. Washington, D.C.: Ireland Press.

13 Intersection Data

14 Land Use Mix: Relationships with Walking People who live near multiple and diverse retail opportunities tend to make more frequent, more specialized and shorter shopping trips, many by walking People who live farther away from retail opportunities are more likely to chain together multiple shopping destinations, and to use a car The more varied the land use mix, the more varied and interesting the built-form, then the more conducive it is to walk to various destinations

15 Land Use Mix: Measurement The degree to which different land uses are scattered within the land area measured by an entropy score GIS databases that can identify land use mix: Land use and zoning data Shopping centres (retail location data)

16 Land Use Data

17 Net Retail Area: Relationships With Walking More options for destinations where goods and services may be purchased More local employment opportunities that can be reached by walking

18 Net Retail Area: Measurement the average ratio of the retail gross floor space to the land area GIS databases to identify the attribute: Shopping Centres (location & retail census data)

19 Creating an Objective Index of Walkability The Walkability Index is built from Geographic Information Systems (GIS) data: dwelling data road data (intersections) land use and zoning data retail opportunity data Census digital boundaries for census collection districts (CCD) Each component scored put into deciles Components added walkability index

20 HIGH WALKABLE High population density High street connectivity High mixed land use

21 LOW WALKABLE: Low population density Low street connectivity Low mixed land use

22 Neighbourhood Environment Walkability Scale (NEWS) Access to services There are many shops within walking distance of my home. Street connectivity There are many four-way intersections in my local area Places for walking There are footpaths on most of the streets in my local area Aesthetics There are attractive buildings and homes in my local area Traffic I live on or near a main arterial road or busy throughway for motor vehicles Crime There is a lot of petty crime in my local area (e.g., vandalism, shoplifting)

23 Residents Can See the Differences 4 All statistically significantly different (p<.001) Density Land use diversity Land use access Connectivity Aesthetics High walkable neighbourhood Low walkable neighbourhood Leslie E, Saelens, Frank, Owen, Bauman, Coffee, Hugo. Residents perceptions of walkability attributes in objectively different neighbourhoods: a pilot study. Health and Place. 2005:11;

24 Applications of the walkability index Behavioural research selecting communities maximising variability in built environment detect differences in walking behaviours Applied policy research mapping levels of objective attributes guide for policy and planning basis for transportation/development investments

25 Limitations of the walkability index Other attributes? presence/quality of footpaths distances to facilities transit accessibility topography building design/orientation Data quality and integrity Use of an area level measure greater accuracy from a more defined measure defined buffer from a residents household

26 Where to Find Resources See the IPEN website: See the link to GIS Protocols manual: Metropolitan Design Centre, University of Minnesota (Ann Forsyth et al.)

27 International Physical Activity & the Environment Network: The PLACE study: Neighborhood Quality of Life Study (NQLS): Neighborhood Environment Walkability Scale (NEWS):

Walkability of local communities: Using geographic information systems to objectively assess relevant environmental attributes

ARTICLE IN PRESS Health & Place 13 (2007) 111 122 www.elsevier.com/locate/healthplace Walkability of local communities: Using geographic information systems to objectively assess relevant environmental