title: Bicycle guidelines and crash rates on cycle tracks in the United States.
abstract: OBJECTIVE
  We studied state-adopted bicycle guidelines to determine whether cycle tracks (physically separated, bicycle-exclusive paths adjacent to sidewalks) were recommended, whether they were built, and their crash rate.
  
  
  METHODS
  We analyzed and compared US bicycle facility guidelines published between 1972 and 1999. We identified 19 cycle tracks in the United States and collected extensive data on cycle track design, usage, and crash history from local communities. We used bicycle counts and crash data to estimate crash rates.
  
  
  RESULTS
  A bicycle facility guideline written in 1972 endorsed cycle tracks but American Association of State Highway and Transportation Officials (AASHTO) guidelines (1974-1999) discouraged or did not include cycle tracks and did not cite research about crash rates on cycle tracks. For the 19 US cycle tracks we examined, the overall crash rate was 2.3 (95% confidence interval = 1.7, 3.0) per 1 million bicycle kilometers.
  
  
  CONCLUSIONS
  AASHTO bicycle guidelines are not explicitly based on rigorous or up-to-date research. Our results show that the risk of bicycle-vehicle crashes is lower on US cycle tracks than published crashes rates on roadways. This study and previous investigations support building cycle tracks.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA. annelusk@hsph.harvard.edu
authors.forename: Anne C
authors.initials: AC
authors.lastname: Lusk
authors.forename: Patrick
authors.initials: P
authors.lastname: Morency
authors.forename: Luis F
authors.initials: LF
authors.lastname: Miranda-Moreno
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.forename: Jack T
authors.initials: JT
authors.lastname: Dennerlein
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D001642:Bicycling / Q000592:standards* / Q000706:statistics & numerical data*; D004779:Environment Design / Q000592:standards*; D017408:Guidelines as Topic / Q000592:standards*; D006801:Humans; D018570:Risk Assessment; D014481:United States