title: The cost-effectiveness of installing sidewalks to increase levels of transport-walking and health.
abstract: OBJECTIVE
  This study investigated the cost-effectiveness of installing sidewalks to increase levels of transport-walking.
  
  
  METHODS
  Secondary analysis using logistic regression established the association of sidewalks with transport-walking using two transport-walking thresholds of 150 and 60 min/week using Western Australian data (n=1394) from 1995 to 2000. Minimum, moderate and maximum interventions were defined, associated respectively with one sidewalk, at least one sidewalk and sidewalks on both sides of the street. Costs, average and incremental cost-effectiveness ratios were calculated for each intervention and expressed as 'the cost per person who walks for transport for more than 150 min/week (60 min/week) after the installation of new sidewalks'. A sensitivity analysis examined the robustness of the incremental cost-effectiveness ratios to varying model inputs. Costs are in 2012 Australian dollars.
  
  
  RESULTS
  A positive relationship was found between the presence of sidewalks and transport-walking for both transport-walking thresholds of 150 and 60 min/week. The minimum intervention was found to be the most cost-effective at $2330/person and $674/person for the 150 and 60 min/week transport-walking thresholds respectively. Increasing the proportion of people transport-walking and increasing population density by 50% improved the cost-effectiveness of installing side-walks to $346/person.
  
  
  CONCLUSIONS
  To increase levels of transport-walking, retrofitting streets with one sidewalk is most cost-effective.
authors.affiliation: McCaughey Centre, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia. Electronic address: lgunn@unimelb.edu.au.
authors.forename: L D
authors.initials: LD
authors.lastname: Gunn
authors.affiliation: Queensland Centre for Mental Health Research, The University of Queensland, QLD, Australia.
authors.forename: Y
authors.initials: Y
authors.lastname: Lee
authors.affiliation: School of Population Health, The University of Western Australia, WA, Australia.
authors.forename: E
authors.initials: E
authors.lastname: Geelhoed
authors.affiliation: Centre for Excellence in Intervention Prevention Science, Melbourne, VIC, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Shiell
authors.affiliation: McCaughey Centre, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Giles-Corti
mesh_terms: D001315:Australia; D003362:Cost-Benefit Analysis; D003430:Cross-Sectional Studies; D004779:Environment Design / Q000191:economics*; D006801:Humans; D011156:Population Density; D011634:Public Health; D012044:Regression Analysis; D014186:Transportation; D016138:Walking
keywords: Active transportation; Built environment; Economic analysis; Physical activity; Public health