Green=walkable?


Research Centre: Healthy High Density Cities Lab
Active Dates: July 2014 - July 2016

Project title: Green=walkable?: measuring the associations between green space morphology and walking patterns in London among 20,000 respondents in the LTDS.

Project team: Chris Webster (Co-PI), Chinmoy Sarkar (Co-PI), Matthew Pryor (Co-PI), Dorothy Tang (Co-PI), Scott Melbourne (Co-PI), Zhang Xiaohu (Co-I), Ashley Kelly (Co-I).

Project funder: HKU URC-PDF 34th round; FoA dean’s start-up fund; DLA.

Abstract:

Green-space and walking behaviors are intuitively connected. Landscape architects, urban designers and planners tend to use rules of thumb in allocating green space to new and re-fashioned urban spaces, based on inherited wisdom, instinct and a general understanding that ‘proximity to green is good’. This project aims to provide an evidence base for more refined green infrastructure morphologies by quantifying the associations between green morphology and walking. It uses data from London Travel Demand Survey (LTDS) of 2009/10, which administered a one-day travel diary recording route, purpose, timing and mode (broken into discrete stages for 20,000 households systematically sampled from across the city). Green space quantity and morphology was measured from 0.5 metre resolution Blue Sky colour infrared image (NDVI vegetation index), a UKMap spatial database identifying individual street trees, parks and key points of interest (POI) and the Ordnance Survey Integrated Transport Network layer for street networks. Logistical and continuous multi-layer regression models were run to investigate waking behavior (distance walked, routes taken, divergence from shortest path, walk-no-walk) as a function of green space morphology, controlling for PoI, slope, socio-economics, crime, traffic and accessibility.

Objectives:

Specific hypotheses tested include: a positive relationship between street trees and walking; and a positive relationship between park size and walking.

Results:

Results so far include the finding that street trees have a measurable effect on distance walked for commuting and on the decision to walk/not walk; and that large parks tend to have a depressing effect on distance walked and the walk/not-walk decision in commuting.

Outputs:

Published so far:

  • Chinmoy Sarkar, Chris Webster, Matthew Pryor, Dorothy Tang, Scott Melbourne, Zhang Xiaohu, Liu Jianzheng. (2015) Exploring associations between urban green, street design and walking: Results from the Greater London boroughs. Landscape and Urban Planning, 143, Nov, 112-125. (IF 3.04)
  • Webster C, Sarkar S, Melbourne S, Pryor M, Tang D, Kaffay N, (2015) Green equals healthy? Towards an evidence base for high density healthy city research. Landscape Architecture Frontiers, 3(1) pp 8-24.
  • Melbourne S, Webster C, Sarkar C, Xiaohu Zhang, Chiaradia A, Does green space size and size distribution matter in optimizing walking performance of cities? Submitted May 2016.
  • Tang D, Webster C, Zhang X, Sarkar C, Does greenery influence walking route choice: a study of 20,000 LTDS participants in London. To be submitted April 2016.
  • Pryor M, Kelly AS, Webster C, Sarkar C,  Quantifying urban greenery. Submitted June 2016.

Anticipated impact:

We hope that this work will set a new standard for the scientific calibration of green-space standards and design doctrines; providing evidence, for example, for decisions about the size-distribution of green spaces in a new city or new neighbourhood and about which parts of a city’s road grid to target in a street tree investment program.

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UNIVERSITY OF HONG KONG
FACULTY OF ARCHITECTURE