title: Impact of Connecticut's graduated driver licensing system on teenage motor vehicle crash rates.
abstract: BACKGROUND
  In response to high rates of teen motor vehicle crashes (MVCs) many states have enacted graduated driver licensing (GDL) systems. GDL delays full licensure and allows beginners to obtain experience under lower risk conditions. The purpose of this study is to evaluate the impact over the past 10 years to determine its effect on teen MVCs.
  
  
  METHODS
  Connecticut MVC data from 1999 to 2008 were analyzed. Percent change (1999 vs. 2008) in MVC rates per 10,000 registered drivers was calculated by age, gender, during the night restriction (11:00 pm and 5:00 am), and MVCs with passengers. Linear regression analysis estimated the decrease of MVC rates each year.
  
  
  RESULTS
  The MVC rate decreased by 40% for 16-year-old and 30% for 17-year-old drivers. In comparison, rates among 18-year-old, 19-year-old, 25- to 29-year-old, and 30- to 59-year-old drivers were reduced by 16%, 7%, 8%, and 11%, respectively. The MVC rate for 20- to 24-year-old drivers increased by 1%. During nighttime restricted driving times, MVC rates decreased by 54% among 16-year-old and 49% among 17-year-old drivers. The MVC rate with passengers decreased by 65% for 16-year-old and 53% for 17-year-old drivers. In comparison, rates of nighttime and with passenger MVCs among older drivers were significantly less.
  
  
  CONCLUSIONS
  Implementation of Connecticut's GDL system has resulted in significant reductions in MVC rates among novice drivers. This analysis provides a method for other states to examine the impact of their GDL system.
authors.affiliation: Injury Prevention Center, Connecticut Children's Medical Center, University of Connecticut School of Medicine, Hartford, Connecticut 06106, USA. scrogers@ccmckids.org
authors.forename: Steven C
authors.initials: SC
authors.lastname: Rogers
authors.forename: George C
authors.initials: GC
authors.lastname: Bentley
authors.forename: Brendan
authors.initials: B
authors.lastname: Campbell
authors.forename: Kevin
authors.initials: K
authors.lastname: Borrup
authors.forename: Hassan
authors.initials: H
authors.lastname: Saleheen
authors.forename: Zhu
authors.initials: Z
authors.lastname: Wang
authors.forename: Garry
authors.initials: G
authors.lastname: Lapidus
mesh_terms: D000063:Accidents, Traffic / Q000331:legislation & jurisprudence / Q000517:prevention & control / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D001334:Automobile Driving / Q000193:education* / Q000331:legislation & jurisprudence; D003237:Connecticut; D005260:Female; D006801:Humans; D035846:Law Enforcement; D008004:Licensure; D008297:Male; D008875:Middle Aged; D018986:Motor Vehicles / Q000331:legislation & jurisprudence*; D012189:Retrospective Studies; D012574:Schools; D055815:Young Adult