Dissimilar Teen Crash Rates in Two Neighboring Southeastern Virginia Cities with Different High School Start Times

Abstract

R esearch suggests that teens require more than 9 hours of sleep per night in order to function optimally. Insufficient sleep in teens is common 2 and could eventuate in excessive sleepiness 3 and such onerous consequences as academic difficulties, behavioral abnormalities, 4,5 mood disorders and perhaps even increased risk of suicidal ideation. 6 A potential critical consequence of insufficient sleep in teens is drowsy driving. Fall-asleep crashes tend to be severe, and, of these, 55% have been found to occur in individuals who are 25 years or younger. 7 For the years 2007 and 2008, individuals aged 16-20 years had the highest injury rate from motor vehicle crashes. 8 While individuals aged 15 to 20 years represented only 9% of the U.S. population and 6% of licensed drivers for 2007, 19% of all fatalities in the United States were related to young-driver crashes. 9 Early high school start times could contribute to insufficient sleep in teenagers 10 and increased motor vehicle crashes. One study found start time to be the main determinant of wake times in adolescents. 11 A recent study revealed that a 30-min delay in high school start time was associated with 45 min of additional sleep on weekday nights and reduced sleepiness. 12 Thus, later high school start times could result in more sleep and better synchronicity with the circadian phase delay found in teens. 3 Unfortunately, the relationship of high school start times to crash rates has rarely been investigated. One recent study by Danner and Phillips did demonstrate that delaying high school start times reduced vehicle crashes in teens. In Lexington Kentucky, a 1-h delay in high school start times was associated with a 16.5% decline in teen crashes in the ensuing 2 years. 13 Adjacent and demographically similar cities in Southeastern Virginia, Virginia Beach and Chesapeake offer a propitious opportunity to compare further school start times and teen crashes. These adjoining cities have markedly different public high school start times. Virginia Beach begins public high school Study Objectives: 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.

School Start Times for Adolescents

“…Car crash rates for the county that delayed school start times decreased by 16.5% over the 2 years before and after the schoolstart change, whereas those for the state as a whole increased by 7.8% across the same time period. In another recent study conducted in 2 adjacent, demographically similar cities, there were significantly increased teen (16- 61 Finally, the recent study by Wahlstrom et al 54 found a crash rate reduction in 16-to 18-year-olds of 65% and 70%, respectively, in 2 of the 4 high schools studied; notably, the high school with the latest start time (Jackson Hole, WY) had the largest decline in car crashes.…”

School Start Times, Sleep, Behavioral, Health, and Academic Outcomes: A Review of the Literature

“…87 For both cities, teen crashes peaked during the morning commute time. 87 The group went on to perform similar analyses for 2 adjacent counties in central Virginia with different school start times. 88 During the 2009-2010 school year, crash rates among 16-to 18-year-olds were higher (p < .05) in the county with the earlier school start times.…”

Later School Start Time: The Impact of Sleep on Academic Performance and Health in the Adolescent Population

“…Furthermore, empirical evidence points to a positive association between later school start times and reduction of vehicular accident rates (by 16.5%) [120,[126][127][128], potentially by improving vigilance. Abbreviation: WE: weekend; HS: healthcare service; Legend: ↑: "increase" (sleep duration, sleep satisfaction, WE oversleep, sleepiness, school rates, tardies/absences, depressive mood, HS utilization, caffeine use) or "delay" (bedtime, rise time); ↓: "decrease" (sleep duration, sleep satisfaction, WE oversleep, sleepiness, school rates, tardies/absences, depressive mood, HS utilization, caffeine use) or "advance" (bedtime, rise time).…”