Reduced Rate of Teens' Car Crashes Related to Later School Start Time

< Dec. 17, 2008 > -- Research findings suggest an increase in sleep means a sharper teenage driver.

This week a research study was published in the Journal of Clinical Sleep Medicine associating an increase in sleep and later school start time to a decrease in car crash injuries or deaths in teenagers.

Study results showed a decrease in auto accident rates in teenage drivers when local high schools changed the start of classes from 7:30 a.m. to 8:30 a.m. Researchers believe this is because these teenagers received more sleep and were more alert when driving.

After puberty, teenagers are biologically programmed to stay up about an hour later each night, according to the study's co-author, Fred Danner, Ph.D., a psychologist at the University of Kentucky. He adds that this shift in their biological clocks will conflict with the earlier wake up time to attend high school instead of the later wake up time to attend middle school.

"It's as if they are operating on West Coast time in an East Coast world," says Dr. Danner. Teenagers' sleep deprivation is often blamed on computers and staying up late to e-mail friends, he adds. "But there is evidence they get phase-shifted by at least an hour. So you've got biology pushing you later and then you've got the school systems starting an hour earlier. By the end of the week, [kids] are a wreck and our study shows they might actually be in one," says Dr. Danner.

Research Study Findings

In Fayette County high schools in Kentucky, nearly 10,000 students in grades 6 through 12 were surveyed about their sleep habits, daytime functioning, and auto mishaps. The survey was administered twice to each student. The first survey took place in 1998, when school started at 7:30 a.m., and the second survey occurred in 1999, when the school start time was delay by one hour to 8:30 a.m.

Two years after the implementation of the one-hour delay in school start time, researchers reported a 16.5 percent decrease in car crashes. During this implementation phase, the number of students who received at least eight hours of sleep per night increased from 35.7 percent in 1998 to 50 percent in 1999. Study results also showed an increase in the average number of sleep hours, and a decrease in catch-up sleep hours on weekends in participants.

Dr. Danner says the average teenager needs at least eight to nine hours of sleep, and as little as an hour less of sleep on school nights can have a cumulative effect. That means, Dr. Danner explains, by the end of the week teens are as impaired as if they had stayed up for 24 hours straight.

Accidents and Fatigue Drivers

According to the National Sleep Foundation, driving fatigue causes around 100,000 accidents per year and over half of these drivers are 16 to 25 years old. In 2006, a survey conducted by the National Sleep Foundation revealed that 28 percent of high school students fall asleep at school and 51 percent have driven a car while drowsy.

Another recent study found that sleep deprivation can lead to safety problems for college students. At the University of North Texas, 262 students were surveyed and found 17 percent of them reported falling asleep while driving.

"If you sleep longer and you are less sleepy, you are less likely to have a wreck. It simply stands to reason," says Dr. Francisco Perez-Guerra, former director of the Scott & White Sleep Disorders Center at Texas A&M University. "We have been talking about later morning starts for children for years," he adds. "This is not a brand new thought."

However, there are practical and political obstacles to overcome before school systems can change the morning schedule for high school students. "If it could be done, it should be done. The question is, can it be done?" he asks.

What are the statistics?

According to the Centers For Disease Control and Prevention (CDC), 4,544 teenagers, between the ages of 16 to19, died of injuries caused by motor vehicle crashes in the United States in 2005. In the same year, around 400,000 teenagers in the same age group were treated in hospital emergency departments for nonfatal motor vehicle injuries. Overall, in 2005, 12 percent of teenage deaths were due to motor vehicle accidents.

Young adults between the ages of 15 to 24 represent only 14 percent of the US population. However, they account for 30 percent ($19 billion) of the total costs of injuries sustained from motor vehicle accidents among males, and 28 percent ($7 billion) of the total costs of injuries among females.

Always consult your physician for more information.

Safety and Injury Prevention Tips for Teenage Drivers

Although teen drivers, between the ages of 16 and 19, constitute almost 10 percent of all licensed drivers, they are involved in 12 percent of fatal motor vehicle-related crashes. According to the American Academy of Pediatrics (AAP), a 16-year-old driver is more than 20 times as likely to have a motor vehicle crash than any other licensed driver. In fact, the leading cause of death among 16- to 20-year-olds is motor vehicle-related crashes.

There are two main reasons why teenage drivers are at increased risk for motor vehicle-related crashes that result in injury or death, including the following:

• lack of driving experience - this means the teenage driver is less able to detect and respond to traffic hazards, less in control of his/her vehicle, and less able to integrate speed.

• risk behavior of teenagers - teenagers tend to take more risks as they are influenced by their emotions, stress, and peer pressure. In addition, experimenting with alcohol and recreational drugs can impair the teenager's driving ability. Also, teenage drivers tend to not use their seat belts, increasing their risk of injury in a crash. According to the AAP, less than one-fourth of high school students say they always wear their seat belts when another person is driving.
  

Another contributing factor to the increased risk to teenager drivers includes nighttime driving. Nighttime driving is more difficult for anyone, especially the novice driver. However, teenagers tend to do disproportionately more driving at night, increasing their risk of a fatal motor vehicle crash, as compared to daytime driving.

The AAP has made several recommendations to pediatricians in coordination with parents to ensure safer teenage driving. Parents should emphasize to teenagers the importance of safe driving, including the fact that teenagers need to develop driving skills with supervised practice. Also, parents should set examples of good driving for teenagers.

It is important to set limits on teenager's driving privileges, such as a limited number of passengers and/or restricted nighttime driving. Parents should impose penalties for irresponsible driving behavior on teenagers.

Remember to get motor vehicles inspected regularly to make sure they are mechanically safe for teenagers to drive. It is also important to support legislative advocacy that targets a reduction in motor vehicle crashes among teenage drivers, such as graduated licensing systems, stricter minimum driving age laws, and tougher safety belt laws.

Always consult your physician for more information.