title: Do school crossing guards make crossing roads safer? A quasi-experimental study of pedestrian-motor vehicle collisions in Toronto, Canada.
abstract: BACKGROUND
  The presence of school crossing guards has been associated with more walking and more pedestrian-motor vehicle collisions (PMVCs) in area-level cross-sectional analyses. The objectives of the study were to (1) Determine the effect on PMVC rates of newly implemented crossing guards in Toronto, Canada (2) Determine where collisions were located in relation to crossing guards throughout the city, and whether they occurred during school travel times.
  
  
  METHODS
  School crossing guards with 50 m buffers were mapped along with police-reported child PMVCs from 2000-2011. (1) A quasi-experimental study identified all age collision counts near newly implemented guards before and after implementation, modeled using repeated measures Poisson regression adjusted for season and built environment variables. (2) A retrospective cohort study of all child PMVCS throughout the city to determine the proportions of child PMVCs which occurred during school travel times and at guard locations.
  
  
  RESULTS
  There were 27,827 PMVCs, with 260 PMVCs at the locations of 58 newly implemented guards. Repeated measures adjusted Poisson regression found PMVCs rates remained unchanged at guard locations after implementation (IRR 1.02, 95 % CI 0.74, 1.39). There were 568 guards citywide with 1850 child PMVCs that occurred at guard locations. The majority of child PMVCs occurred outside school travel times (n = 1155, 62 %) and of those that occurred during school travel times, only 95 (13.7 %) were at a guard location.
  
  
  CONCLUSIONS
  School crossing guards are a simple roadway modification to increase walking to school without apparent detrimental safety effects. Other more permanent interventions are necessary to address the frequency of child PMVCs occurring away from the location of crossing guards, and outside of school travel times.
authors.affiliation: Child Health Evaluative Sciences, Toronto, Canada. linda.rothman@sickkids.ca.|Faculty of Health-School of Kinesiology & Health Science, York University, Toronto, Canada. linda.rothman@sickkids.ca.
authors.forename: Linda
authors.initials: L
authors.lastname: Rothman
authors.affiliation: Orthopaedic Surgery, The Hospital for Sick Children, Toronto, Canada. danperry@doctors.org.uk.|Division of Health Sciences, Warwick Medical School, Warwick University, Coventry, UK. danperry@doctors.org.uk.
authors.forename: Daniel
authors.initials: D
authors.lastname: Perry
authors.affiliation: Department of Geography, University of Toronto Mississauga, Mississauga, Canada. ron.buliung@utoronto.ca.
authors.forename: Ron
authors.initials: R
authors.lastname: Buliung
authors.affiliation: Child Health Evaluative Sciences, Toronto, Canada. colin.macarthur@sickkids.ca.|Department of Pediatrics, University of Toronto, Toronto, Canada. colin.macarthur@sickkids.ca.|Health Policy Management and Evaluation, University of Toronto, Toronto, Canada. colin.macarthur@sickkids.ca.
authors.forename: Colin
authors.initials: C
authors.lastname: Macarthur
authors.affiliation: Child Health Evaluative Sciences, Toronto, Canada. teresa.to@sickkids.ca.|Health Policy Management and Evaluation, University of Toronto, Toronto, Canada. teresa.to@sickkids.ca.|Dalla Lana School of Public Health, University of Toronto, Toronto, Canada. teresa.to@sickkids.ca.
authors.forename: Teresa
authors.initials: T
authors.lastname: To
authors.affiliation: Faculty of Health-School of Kinesiology & Health Science, York University, Toronto, Canada. alison3@yorku.ca.
authors.forename: Alison
authors.initials: A
authors.lastname: Macpherson
authors.affiliation: Child Health Evaluative Sciences, Toronto, Canada. kristian.larsen@utoronto.ca.|Department of Geography, University of Toronto Mississauga, Mississauga, Canada. kristian.larsen@utoronto.ca.
authors.forename: Kristian
authors.initials: K
authors.lastname: Larsen
authors.affiliation: Child Health Evaluative Sciences, Toronto, Canada. andrew.howard@sickkids.ca.|Orthopaedic Surgery, The Hospital for Sick Children, Toronto, Canada. andrew.howard@sickkids.ca.|Department of Surgery, University of Toronto, Toronto, Canada. andrew.howard@sickkids.ca.|Health Policy Management and Evaluation, University of Toronto, Toronto, Canada. andrew.howard@sickkids.ca.
authors.forename: Andrew
authors.initials: A
authors.lastname: Howard
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data; D000328:Adult; D002648:Child; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004779:Environment Design; D006801:Humans; D035846:Law Enforcement / Q000379:methods*; D008297:Male; D009864:Ontario; D012189:Retrospective Studies; D012574:Schools; D012637:Security Measures / Q000706:statistics & numerical data*; D016138:Walking / Q000293:injuries / Q000706:statistics & numerical data; D055815:Young Adult