title: Dissimilar teen crash rates in two neighboring southeastern Virginia cities with different high school start times.
abstract: OBJECTIVE
  Early high school start times may contribute to insufficient sleep leading to increased teen crash rate. Virginia Beach (VB) and Chesapeake are adjacent, demographically similar cities. VB high schools start 75-80 minutes earlier than Chesapeake's. We hypothesized that VB teens would manifest a higher crash rate than Chesapeake teens.
  
  
  METHODS
  The Virginia Department of Motor Vehicles (DMV) provided de-identified, aggregate 2008 and 2007 data for weekday crashes and crash times in VB and Chesapeake for drivers aged 16-18 years ("teens"), and provided 2008 and 2007 crash data for all drivers. Data allowed comparisons of VB versus Chesapeake crash rates for teens (overall and hour-by-hour), and teens versus all other ages. We compared AM and PM traffic congestion (peak hours) in the two cities.
  
  
  RESULTS
  In 2008, there were 12,916 and 8,459 Virginia Beach and Chesapeake 16- to 18-year-old drivers, respectively. For VB and Chesapeake, teen drivers' crash rates in 2008 were 65.8/1000 and 46.6/1000 (p < 0.001), respectively, and in 2007 were 71.2/1000 and 55.6/1000. Teen drivers' crash peaks in the morning occurred one hour earlier in VB than Chesapeake, consistent with school commute time. Congestion data for VB and Chesapeake did not explain the different crash rates.
  
  
  CONCLUSIONS
  A significantly increased teen crash rate for both 2008 and 2007 occurred in VB, the city with earlier high school start times. Future studies using individual level data may clarify if sleep restriction, circadian dyssynchrony, and sleep inertia might contribute to this increased crash rate.
authors.affiliation: Division of Sleep Medicine, Department of Internal Medicine, Eastern Virginia Medical School, 600 Gresham Drive, Sentara Norfolk General Hospital, Eastern Virginia Medical School/Sentara Norfolk General Hospital Sleep Disorders Center, Norfolk, Virginia 23507, USA. voronard@evms.edu
authors.forename: Robert Daniel
authors.initials: RD
authors.lastname: Vorona
authors.forename: Mariana
authors.initials: M
authors.lastname: Szklo-Coxe
authors.forename: Andrew
authors.initials: A
authors.lastname: Wu
authors.forename: Michael
authors.initials: M
authors.lastname: Dubik
authors.forename: Yueqin
authors.initials: Y
authors.lastname: Zhao
authors.forename: J Catesby
authors.initials: JC
authors.lastname: Ware
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000293:Adolescent; D000367:Age Factors; D006801:Humans; D012574:Schools / Q000458:organization & administration*; D012890:Sleep; D013997:Time Factors; D014768:Virginia