The walkability analysis incorporated measures of intersection density (the number of intersections per unit area), land use (land zoning category), road speed (30, 50, and 100 km/h zones), population density (total population per square kilometer), and slope. These are important factors in a walkability analysis, however, this study aimed to develop a pediatric walkability index and needed to be modified as such. While other pediatric walkability studies have included factors such as neighbourhood perception and pedestrian features (lighting), it was decided that as contributing factors to the safety component of the final playability MCE, these factors should not be accounted for in the walkability analysis as well. While the walkability index contains features often attributed to an adult walkability index, aspects of pediatric walkability were included when possible.
The pediatric modifications to the walkability index included: an intersection density layer which accounts for all intersections, and not just those of main roads, in an attempt to capture the total network traveled by children; the land use layer ranks zoning types according to appropriateness for children; and the road speed layer identifies park and school zones, not just roads with speeds below 50km/h. However, non-traditional networks (trails and greenways) could not be identified, although alleyways were accounted for in the intersection density layer.
The interactive map below identifies pediatric walkability throughout the City of Vancouver. Walkability is organized into five classes representing the highest to lowest walkability scores in the city.
The population density layer was created using information from the 2011 Canadian Census. The total population of each DA was divided by the area of each to provide a total population density. Those areas with higher population densities are more likely to be well developed, and to have more people out in public, thus contributing to the perceived safety of that neighbourhood. This shapefile was converted to a raster layer for incorporation in the walkability MCE. Click here to view the population density map
Intersection density was calculated using a road network file that was obtained from the British Columbia Data Catalogue. The roads shapefile was loaded into ArcGIS and was then used to create a network dataset. The network dataset tool generated junction points at every intersection, and this point shapefile was then used to calculate intersection density. Intersection density was calculated using the ArcGIS point density tool, and the resulting raster layer was formulated for export to IDRIS for the walkability MCE. Neighbourhoods with higher intersection densities are considered more suitbale for walking, as they have higher connectivity and allow for easier travel between points. Click here to view the intersection density map
A 50 meter resolution digital elevation model (DEM) was obtained from the British Columbia Data Catalogue and was clipped to the boundaries of the City of Vancouver. The ArcGIS slope spatial analyst tool was used to convert the digital elevation data into slope values. The resultant raster layer provided a range of slope values that were included in the walkability MCE. Slope was included in the analysis because a lower slope angle is more suitable for walking and is more likely to be travelled along by children. Click here to view the slope map
Land use information was obtained from the City of Vancouver’s zoning shapefile. The different zones contained within this shapefile were grouped according to similarity and ranked. The most suitable areas for children (residential) were given a ranking of one, and the least suitable (industrial) were ranked as a five. Commercial zones, historic areas, and the limited amount of agricultural land were given a score of two, and comprehensive developments ranked as three. Click here to view the land use map
The speed limits for the roads within the city were assigned to the roads shapefile using the road classification information contained within the data. All alleyways were assigned a speed of 30 km/h, all city streets were assigned a speed of 50 km/h, and all highways a speed of 100 km/h. Since school zones and park zones were not identified within the shapefile, a 200m buffer was constructed around all parks and schools. The buffer was then used to clip the roads file, and a speed of 30 km/h was assigned to all of the road segments within 200m of a park or school. The roads with the lowest speed limit were considered to be the safest for children to walk along. Click here to view the road speed map
Each of the above data layers were organized in IDRISI upon completion to calculate the overall walkability index using the IDRISI Decision Wizard. The values of each raster layer were organized into fuzzy sets, providing a standardized range of values for each layer on a scale of 0-255. Each of these factors was given equal weight in the walkability analysis. Research on walkability and pediatric walkability did not identify one factor as the single most important, nor did it compare one factor to the next. The final output can be seen in the above interactive map.