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Stress response may help teens avoid car accidents

A little stress may be a good thing for teenagers learning to drive.

In a new study, teens whose levels of the stress hormone cortisol increased more during times of stress, got into fewer car crashes or near crashes in their first months of driving than their less-stress-responsive peers did.  The study suggests that biological differences may affect how teens learn to respond to crises on the road, the researchers reported April 7 in the journal JAMA Pediatrics.

Efforts to reduce teen car accidents include graduated driver licensing programs, safety messages and increased parental management, but these efforts seem to work better for some teens than others, the researchers said. Alternatives, such as in-vehicle technologies aimed at reducing accidents, may be especially useful for teens with a "neurological basis" for their increased risk of getting into an accident, they said.

The neurobiology of risk

Automobile accidents are the No. 1 cause of death of teenagers in the United States, according to the Centers for Disease Control and Prevention. Car crashes also kill more 15- to 29-year-olds globally than any other cause, according to the World Health Organization. [Top 10 Leading Causes of Death]

For the study, Marie Claude Ouimet, a professor of community health at the University of Sherbrooke in Quebec, and her colleagues recruited 42 teens in Virginia, and fitted their cars with video cameras, accelerometers, GPS and mileage recorders to record the teens' crashes and near misses during their first 18 months of driving.  They also took saliva samples from the 16-year-olds as they struggled with a series of stressful math problems, measuring how much the teens' cortisol levels rose during this stress test.

Stress and learning

The results revealed that the more responsive a teen's cortisol levels were to stress, the fewer crashes and near misses they experienced per mile driven, and the faster they saw their rates of crashing or nearly crashing drop.

The study was limited in that the participants were wealthier and healthier than all teenagers on average, and there were only a few, minor crashes during the experiment. Nevertheless, the findings suggest teens' stress responses are linked with their risk of getting into accidents, wrote Dr. Dennis R. Durbin, of the Center for Injury Research and Prevention at The Children's Hospital of Philadelphia, and colleagues in an editorial accompanying the study.

"[A]s teens gain independent driving experience, they are exposed to a variety of emotionally evocative stimuli such as near misses with unexpected hazards which enables them to better anticipate, avoid and react more effectively in the future," wrote Durbin and his colleagues, who were not involved in the research.

The hypothalamic-pituitary-adrenal (HPA) axis, which consists of brain regions and glands responsible for the stress response and for releasing cortisol, may influence how a teen handles these stimuli, the researchers suggested. Teens with a more reactive HPA may develop defensive-driving skills more quickly, they said.

 MY ASSESSMENT:  Interesting study, but the results are suspect.  Is there doubt these these young drivers behave a bit differently with so much observational equipment in the car?  Slower, more cautious, etc...?  We can anticipate fewer accident from that alone.  

Nice study, but the results are likely skewed.

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Distracted Driving Campaign Targets 'Myth' of Hands-Free Safety

Safety advocates want motorists to pay attention to the dangers of distracted driving. As April is designated "Distracted Driving Awareness Month", the century-old Itasca, Ill.-based National Safety Council has released a new poll showing that 80 percent of drivers across the U.S. believe hands-free devices are safer than using a handheld phone while behind the wheel. The group believes this not to be the case. Meanwhile, among motorists reporting using hands-free devices while driving, 70 percent said they do so for safety reasons.

"While many drivers honestly believe they are making the safe choice by using a hands-free device, it's just not true," said David Teater, the NSC's senior director of transportation initiatives. "The problem is the brain does not truly multitask. Just like you can't read a book and talk on the phone, you can't safely operate a vehicle and talk on the phone."

Confusing matters, NSC says, many states have laws prohibiting the use of handheld cellphones while driving, though no state has yet banned the use of hands-free devices. Likewise, automakers continue to incorporate hands-free communication technologies into their vehicles.

NSC fears this sends a dangerous mixed message to drivers that the availability of and lack of restrictions on hands-free devices means they're safe; certain statistics show the opposite, linking thousands of deaths each year as a result of cellphone use while driving.

To help spread the word on distracted driving, NSC has compiled these facts to show the dangers:

About 100 people die in car crashes every day;

90 percent of car crashes are caused by driver error;

26 percent of all car crashes involve mobile-phone use, including hands-free devices, which at any moment are being used by 9 percent of drivers.

With regard to what NSC calls the "big fat myth" of multitasking, activity in the area of the brain that processes moving images decreases by as much as one-third when listening to talking on a phone, and drivers looking out the windshield miss as much as 50 percent of what's around them due to a narrowing of their field of view, NSC reported.

Concerning emerging technologies, NSC reports that new studies show using voice-to-text is actually more distracting than typing texts by hand.

Underscoring those eye-opening stats, the U.S. government's official distracted-driving website, Distraction.gov, calls the practice "a dangerous epidemic" that in 2012 alone resulted in 3,328 driving deaths. The problem is of particular concern among teens and young people — 71 percent have composed and sent text messages while driving, and 78 percent of whom have read messages, according to the National Highway Traffic Safety Administration.

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Cellphone use causes over 1 in 4 car accidents

Drivers are constantly reminded not to use their phones while behind the wheel, but a new study reminds us just how dangerous it is.

The National Safety Council's annual injury and fatality report, "Injury Facts," found that the use of cellphones causes 26% of the nation's car accidents, an increase from the previous year. The 2014 edition of the report compares data from 2013 and earlier.  Only 5% of cellphone-related crashes occur because the driver is texting. The majority of the accidents involve drivers distracted while talking on handheld or hands-free cellphones.

The NSC report, combined with Texas A&M research institute's "Voice-to-Text Driver Distraction Study," warns drivers that talking can be more dangerous than texting while operating a vehicle, and the use of talk-to-text applications is not a solution.  For most phone-related tasks, Texas A&M's survey said manual texting took slightly less time than the voice-to-text method. Regardless, driver performance was almost equally affected during both tasks.

In early 2013, the nation's four biggest cellphone companies launched their first joint advertising campaign against texting while driving. Verizon Wireless, Sprint and T-Mobile united behind AT&T's "It Can Wait" advertising campaign, warning their customers against the misuse of their own devices.

However, hands-free cellphone use has become a driving force in cellphone-related distractions of those behind the wheel. Studies published as early as 2009, such as a report in the Journal of Safety Research, have said that driving performance while using a hands-free phone was rarely found to be better than using handheld devices.

In the full NSC report, the organization lists and rates different tasks in relation to the effect they have on a driver's mental workload, using data collected from a cognitive study. On the cognitive distraction scale, driving and talking on a handheld phone has a 2.45 workload rating, and driving while talking on a hands-free cellphone has a 2.27 workload rating.

On the same scale, using the speech-to-text application while driving has a 3.06 workload rating.  According to NSC's website, there have been an estimated 245,358 car crashes involving drivers using cellphones so far this year. One effect cellphone use has on drivers is an increased reaction time, which is similar regardless of handheld or hands-free phone use.

Using data from 2011, NSC partnered with Nationwide Insurance to report the most accurate number of fatalities caused by cellphone-related vehicular accidents. National data show cellphones were involved in 350 fatal crashes in 2011.

The 2014 NSC report says the percent of drivers observed manipulating handheld electronic devices increased from 0.9% in 2010 to 1.3% in 2011.

The data collected on accidents and fatalities caused by cellphone use on the road is said to be under-reported due to the lack of drivers willing to admit to using their phones.

So far, 12 states, D.C., Puerto Rico, Guam and the U.S. Virgin Islands have made it illegal to use handheld devices while driving, according to the Governors Highway Safety Association. Out of the 43 states that have banned texting while driving, all but five have primary enforcement of their laws, meaning an officer may cite a driver for texting without any other traffic violation taking place.

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