title: The impact of pedestrian countdown signals on single and two vehicle motor vehicle collisions: a quasi-experimental study.
abstract: The objective of this study was to examine the impact of pedestrian countdown signals (PCS) on the rate of motor vehicle collisions (MVCs) in Toronto, Canada. A quasi-experimental design was used to compare rates of single and two vehicle MVCs before and after installation of PCS in Toronto, Canada between January 2005 and December 2009. Collision incidence rates were compared using Poisson regression analyses with adjustment for relevant cofounders and reported as incidence rate ratios (IRR) with 95% confidence intervals (CI). Secondary analyses were performed on subsets of collisions by collision type and injury severity. A total of 94,175 MVCs occurred at or near 1965 intersections at which PCS were installed over the five-year study period. Overall, the MVC incidence rate increased 7.5% (IRR = 1.075; 95% CI: 1.042-1.109; p < 0.0001) after installation of PCS. The installation of PCS led to an increase in MVCs. PCS may have an unintended consequence of increasing the rate of MVCs.
authors.affiliation: a Division of Orthopaedic Surgery , University of Toronto , Toronto , Canada.
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Escott
authors.affiliation: b Child Health Evaluative Sciences , The Hospital for Sick Children , Toronto , Canada.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Richmond
authors.affiliation: b Child Health Evaluative Sciences , The Hospital for Sick Children , Toronto , Canada.|c Dalla Lana School of Public Health , University of Toronto , Toronto , Canada.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Willan
authors.affiliation: a Division of Orthopaedic Surgery , University of Toronto , Toronto , Canada.
authors.forename: Bheeshma
authors.initials: B
authors.lastname: Ravi
authors.affiliation: b Child Health Evaluative Sciences , The Hospital for Sick Children , Toronto , Canada.|d Division of Orthopaedic Surgery , The Hospital for Sick Children , Toronto , Canada.|e Institute of Health, Policy, Management and Evaluation , University of Toronto , Toronto , Canada.|f Department of Surgery , University of Toronto , Toronto , Canada.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Howard
mesh_terms: D000056:Accident Prevention / Q000295:instrumentation*; D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D004779:Environment Design; D006801:Humans; D015994:Incidence; D065186:Interrupted Time Series Analysis; D009864:Ontario; D012307:Risk Factors; D015599:Trauma Severity Indices
keywords: Canada; accidents; motor vehicles; traffic/prevention and control