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Table 2 Existing built environmental measures

From: GIS measured environmental correlates of active school transport: A systematic review of 14 studies

Environmental measures

Definition/formula/GIS methods

Scale of measuring the variables

 

Distance

   

Distance to school

Shortest path to school along the circulation system (including roads, trails, and pathways) estimated by GIS/ArcView 3.x extension, Network Analyst V1.0b estimated the distance based on the shortest route possible along road network

--

[17, 23, 27, 28]

 

Straight-line distance between home and schools

--

[21, 25, 26]

 

Manhattan distance between school and home

--

[18]

 

Not reported

 

[29]

Distance to Central Business District

Distance between the Toronto Central Business District and Traffic Analysis Zone of a respondent's home

--

[25]

Density

   

Residential/dwelling density

The ratio of residential units to the residential area

Block group/Traffic Analysis Zone

[16, 18, 23]

 

Total number of residents per land area

Block group

[20, 26]

 

The ratio of total number of residents to the residential area (and commercial use)

Block group

[23, 29]***

Residential index

Residential units as a percent of dwelling units and total employment in the traffic analysis zone

Traffic Analysis Zone

[18]

Employment density

Number of employees per land area

Traffic Analysis Zone

[18]

 

Employment to population ratio

Traffic Analysis Zone

[24]

 

Ratio of sales/service employment to the population

Traffic Analysis Zone

[25]

 

Ratio of manufacturing/trade/office/professional employment to the population

Traffic Analysis Zone

[25]

 

Number of employees per area of industrial and commercial land

Unknown

[29]

Building density

Area of floor space/buildings per land area

Study area

[27, 29]

School density

Number of school per land area

Traffic analysis zone

[24]

Density of school- or work-related trips

Walking density-total work and school related walking trips produced by residents in study area

Traffic Analysis Zone

[25]

Vehicle density

Number of cars and motorcycles per area of roads

Study area

[29]

Diversity

   

Mixed land use

Land Use Entropy

Block group/Traffic Analysis Zone

[16, 18, 23, 29]***

 

Herfindahl-Hirschman index-proportion of each land use squared and summed

Not reported

[27]

Land use intensity for commercial properties

Commercial floor area ratio (FAR) = commercial floor area/commercial land area

Not reported

[19]

Retail floor area ratio

Retail building square footage/retail square footage

Block group

[16]

Design-connectivity-intersections

  

Intersection density

The ratio of number of intersections 3- to 4-way or 3- to 5-way or not specified) to the land area/street length

Block group/study area

[1618, 20, 23, 27]

 

Number of major road intersection (3 or 4-way) per land area (primary highway, secondary highway and major/arterial roads)

Study area

[25]

 

Number of 4-way local street intersections

Study area

[25]

 

Intersection number along the route to school

Study area

[29]

Percent of 1,3,4, and 5-way intersections

Percent of 1,3,4, and 5-way intersections with the buffer

Study area

[18]

Connected node ratio

The ratio of number of intersections to number of intersections and cul-de-sacs

Study area

[27]

Cul-de-sac density

The ratio of number of cul-de-sac to land area

Not reported

[17]

Design-connectivity-route directness

  

Pedestrian route directness

The ratio of the distance to school along the road network to the straight-line distance

--

[17, 27, 28]

Design-connectivity-streets

  

Block/road density

Road length (local streets, arterials, and collectors) or number of blocks per land area

Study area

[19]*** [25, 27, 29]***

Average block size

Not reported

Study area

[18, 29]

Length of each types of road or all streets

Total length of motorway, main street, and side street (Switzerland) in each study area

Study area

[26]

Proportion of primary road

Length of primary roads per length of all roads

 

[27]

Vehicle lane width

Average width of vehicle lanes along the route to school

Study area

[29]

Design-sidewalk and bike lanes

  

Sidewalk/walking tracks length

Total length of sidewalk/walking tracks in the study area

Study area

[23]

Average sidewalk width

Not reported

Not reported

[19]

 

Average sidewalk width along the route to school

Study area

[29]

Sidewalk density

Proportion of street miles with sidewalk/pavement

Study area

[19]*** [27]

 

Percentage length of sidewalks with widths wider than two metres along the route to school

Study area

[29]

Bike lane density

Proportion of street miles with bike lanes or paved shoulders

Not reported

[19]

Street spatial design

  

Across a motorway, main street or a side street/across busy road (freeway, highway, arterial, subarterial, collector, and local road)/across major roads, or rail roads

Whether the route to school cross these road

Along the estimated route to school/the straight line between school and home

[17, 26, 28]

Route along busy/main or secondary road

Whether the route to school along a busy/main or secondary road

Along the estimated route to school

[27, 28]

Route along

   

Road outside child's home

A major or minor road adjacent to the child's home

--

[27]

Proportion of primary roads

Presence of primary road as part of the route

Along the estimated route to school

[27]

Walkability index

   

Neighbourhood walkability index

Walkability=[(z net residential density) = (z retail floor area ratio) + (2 × z intersection density) + (z land use mix)]

Cluster of block groups

[16]

Individual walkability index

Walkability=[(z net residential density) = (z retail floor area ratio) + (2 × z intersection density) + (z land use mix)]

Study area

[16]

Effective walkable area

Total neighbourhood area (area that can be reached via the street network within 800 m from the home) divided by the potential walkable area (the area generated using a circular buffer with a radius of 800 m from the home)

Study area

[27]

Topography and aesthetics

  

Greenery

Proportion of street miles with street trees

Not reported

[19]

 

Total number of street trees within 5 m of each road edge

Study area

[23]

 

Number of shade trees per the length of route to school

Study area

[29]

Steep incline

Altitude between home and school; detail not reported

Along the straight line between school and home

[26]

 

A TIN (triangulated irregular network) file was created from the digital elevation model (data from the State of Victoria). Surface analysis was undertaken along each route to determine the presence of a steep incline along any segment using Surface Tools, version 1.5.

Along the estimate route to school

[28]

 

Average slope gradient within residence area of a child

Not reported

[29]

Geographic regions

Northeast, South, Mideast, or West in the US

--

[22]

Urbanisation

Population density>4150 persons per square mile (ppsm) = urban; 1000-4150 ppsm = suburban; <1000 ppsm = rural

Not reported

[21]

 

Five levels of urbanisation defined by quintiles of population density and density of the surrounding areas: urban, metro suburban, second city, town, and rural

Not reported

[22]

 

Urban, inner-suburban, outer-suburban

Traffic analysis zone

[24]

 

Urban or rural based on address of child's home

--

[27]

Proportion of route to school within an urban area

Proportion of route that passes through urban area

Along the estimated route to school

[27]

Safety

   

Traffic accidents

Number of fatal or serious road traffic accidents divided by total road length

Study area

[27]

Streetlight density

Number of streetlights divided by total road length

Study area

[27]

Demographic-socio-economic status

  

Area-level socioeconomic status score

Based on the Australian Bureau of Statistics' Index of Relative Socio-Economic Advantage/Disadvantage

Not reported

[28]

Neighbourhood income

Median household income

Block group/Dissemination area

[16, 23]* [24, 25]

Socioeconomic deprivation

Population weighted scores for index of multiple deprivation

Not reported

[27]

Percent of residents on public assistance

 

Census tract

[18]**

Percent of household with income below poverty level

 

Block group/Census tract

[18]**

Percent of residents unemployed

 

Census tract

[18]**

Demographic-education

  

Educational attainment at neighbourhood level

Proportion of population over age 25 years with high school diploma

Block group

[23]*

Demographic-housing

  

Percent of residents living in owner-occupied housing

 

Block group/Census tract

[18]**

Percent of residents living in the same house as 1995

 

Census tract

[18]**

Percent of residents living in female headed households

 

Block group/Census tract

[18]**

Demographic-ethnicity

  

Percent of persons born abroad

 

Block group/Census tract

[18]**

Percent of non-white residents

 

Block group/Census tract

[18]**

Demographic-single parenthood

   

Single parenthood

Proportion of families headed by single parents

Block group

[23]*

  1. *Canadian equivalent: dissemination area
  2. **Census Tract is a geographic unit comparable to Traffic Analysis Zone which was used to measure other variables.
  3. ***Scale of measuring variables is not reported.