Businessman devouring fries whilst driving car © Ryan McVay, Photodisc, Getty Images

Driving is a part of everyday life for most Americans. It's so mundane that we rarely think of the potential danger that exists around every bend in the road. Car insurance companies are aware of those risks and price their policies accordingly.

But there are dangers not only on the road -- they're also inside the vehicle, as illustrated by a study from the AAA Foundation for Traffic Safety.

It looked at a number of activities and how likely they are to cause "cognitive distraction" -- in other words, a tendency for a driver's mind to wander. Bruce Hamilton, the AAA foundation's research manager, says testing revealed that some in-vehicle distractions have little impact on a driver's ability to focus on the road, while others present a bigger danger.

In addition, some technological innovations designed to make driving safer may fail to do so, he says.

"Hands-free doesn't mean risk-free, and this is the best evidence to date that shows that," Hamilton says.

Following are some of the distractions AAA examined, and how they rank on the danger scale.

Listening to the radio: Minimal risk

AAA looked at several potentially hazardous distractions that can divert a driver's attention.

Participants in the study were asked to perform each task in three separate settings:

  • While not driving.
  • While driving in a simulator.
  • While driving a car in a real-world situation.

Various measures were used to determine the level of distraction, including brake reaction time and following distance, brainwave activity, and eye and head movements.

In the early stages of testing, the subjects listened to the radio. They adjusted the radio to a comfortable volume before driving and then were not allowed to change the station.

The bottom line? Using your car's radio to hum along with your favorite tunes or to catch up on the latest news does not significantly distract you, the study found.

"We are not raising the alarm about people listening to the radio," Hamilton says.

Listening to a book on tape: Minimal risk

In this section of the study, participants were asked to choose and listen to a section from one of three audio books. (And, for you trivia buffs, the passages were from: "The Giver" by Lois Lowry; "Water for Elephants" by Sara Gruen; and "Harry Potter and the Sorcerer's Stone" by J.K. Rowling.)

Participants then were given a simple five-question quiz about the contents of the passage to ensure they were listening carefully.

The level of distraction when drivers become engrossed in an audio book was slightly higher than when drivers merely listened to the radio.

However, Hamilton says the difference is not significant enough to warrant alarm, and that overall distraction levels remained relatively low.

Talking to a passenger: Moderate risk

The level of distraction became a bit more elevated when test participants chatted with a passenger in the car.

As part of the testing, drivers were asked to have a conversation with a passenger. Participants were asked to spend roughly half the time talking, and the other half listening.

Distraction levels rose about halfway between activities that are not distracting at all, and those that are severely distracting.

Interestingly, it appears that the mere act of conversation is distracting. Drivers were not allowed to turn their heads to look at the passenger while talking, nor to perform actions such as hand gestures that might lead to distraction.

"They were told to keep their eyes on the road and hands on the wheel the whole time," Hamilton says.

Hand-held cellphone use: Moderate risk

For years, auto safety advocates, car insurance companies and other critics have blamed hand-held cellphones for causing significant distractions and leading to accidents and fatalities.

As a result, more than 10 states plus the District of Columbia have banned all drivers from using hand-held phones. D.C. and a majority of states prohibit novice drivers from using a hand-held cellphone behind the wheel.

The AAA test did indeed find that talking on a cellphone causes elevated levels of distraction.

Jonathan Adkins, deputy executive director of the Governors Highway Safety Association, says drivers should not try to multitask when driving and should put away their phones.

He says the association continues to encourage all states to ban both hand-held cellphone use and texting by drivers.

"Any type of cellphone use while driving is dangerous," Adkins says. "The best practice is to turn the phone off and focus on driving."

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Hands-free cellphone use: Moderate risk

Hands-free cellphone technology has been touted as a solution to phone-based driver distractions. But the AAA researchers found about the same amount of risk as with hand-held phones.

David Teater, senior director of transportation strategic initiatives at the National Safety Council, says he is not surprised.

"Hands-free does not prevent cognitive distraction," he says.

Other experts have reached the same conclusion. A 2010 study by the Highway Loss Data Institute, a research organization supported by car insurance companies, found no reduction in crashes in states that banned hand-held devices while driving and said the risk is about the same, whether phones are hand-held or hands-free.

Teater says at least 30 major studies have reached similar conclusions.

"The only thing that changes when using hands-free is that one hand goes back on the steering wheel," he says. "We have been driving manual-shift transmissions for years and have not worried about it as a safety hazard."

Speech-to-text systems: Extensive risk

Speech-to-text systems allow drivers to send texts and emails by speaking, then having the technology translate words into a written message. Some systems also allow drivers to complete other tasks, such as updating their Facebook page.

These systems were deemed significantly distracting -- and risky.

"Increased mental workload and cognitive distractions can lead to a type of tunnel vision or inattention blindness where motorists don't see potential hazards right in front of them," explains Peter Kissinger, the president and CEO of the AAA Foundation for Traffic Safety, in a statement.

Hamilton notes that AAA tested a speech-recognition system in which fidelity was perfect. Most commercially available systems do not meet this standard, he says, resulting in a need to review or correct garbled translations. That could mean an even higher level of distraction.

"Our estimate is somewhat conservative," he says.

With the car insurance industry warning that driver distractions can be deadly, researchers are hoping for more dialogue about the safe use of hands-free devices.

"We're not trying to say that these technologies can't be in vehicles," Hamilton says. "We're just trying to put the brakes on their wholesale proliferation."

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