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US research shows hands-free phones just as risky

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Published : Dec. 16, 2011 - 16:36

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WASHINGTON (AP) _ When someone is talking to you, your brain is listening, processing and thinking about what is being said _ even if you are in the driver's seat trying to concentrate on traffic.

That is why drivers get distracted during cellphone conversations, even when using hands-free phones, researchers say. It is also part of the reason why the National Transportation Safety Board made a recommendation this week it knows a lot of drivers will not like _ that states ban hands-free, as well as hand-held, cellphone use while driving.

It is not where your hands are, but where your mind is that counts, NTSB chairman Deborah Hersman told reporters.

The board does not have the power to force states to impose a ban, but its recommendations carry significant weight. And, judging from the public reaction, they have already started a national conversation on the subject. NTSB has been swamped with calls, emails and tweets from drivers both praising and condemning the action.

It is the proposed hands-free ban that has generated the most controversy.

What is next? No passengers? No kids? No tuning the radio? Maybe NTSB will ban driving altogether, was the tenor of the response on Twitter.

The scientific evidence, however, is generally with NTSB, researchers said.

``There is a large body of evidence showing that talking on a phone, whether hand-held or hands-free, impairs driving and increases your risk of having a crash,'' Anne McCartt, senior vice president for research at the Insurance Institute for Highway Safety, said.

Jim Hedlund, a safety consultant and former National Highway Traffic Safety Administration official, recently examined 300 cellphone studies for the Governors Highway Safety Association. He could not recall a single study that showed drivers talking on a headset or hands-free phone were at any less risk of an accident than drivers with one hand on the wheel and a phone in the other.

A similar analysis for the government of Sweden recently came to the same conclusion: ``There is no evidence suggesting that hands-free mobile phone use is less risky than handheld use.''

What is missing is hard evidence that accidents are increasing because of cellphone use. One reason is that U.S. privacy laws have made it difficult for researchers to study whether cell phones were in use in accidents in the U.S. The two large studies that have been done _ in Canada and Australia _ found drivers were four times more likely to have a crash if talking on a cellphone. It did not matter whether the cellphone was hands-free or hand-held.

But that has not translated to an increase in highway fatalities in the U.S., where they hit their lowest level since 1949 last year.

Of 6,000 drivers surveyed by the highway administration, 40 percent said they do not consider it unsafe for drivers to talk on a hands-free cellphone. Less than 12 percent said that about a hand-held phone.

Marcel Just, director of Carnegie Mellon University's Center for Cognitive Brain Imaging, is not surprised.

It is counterintuitive to think that hands-free talking is dangerous because people do not have any sense that their conversation is draining brain power away from driving, but that is exactly what is happening, he said.

Just is the co-author of a 2008 study that used driving simulators to test the performance of drivers not engaged in conversation and drivers who could hear someone talking to them through headphones. Drivers took the simulator tests inside an MRI (magnetic resonance imaging) machine that recorded images of changes in their brains while driving, including which areas of the brain were used for driving. The amount of the brain devoted to driving was 37 percent less in drivers who could hear someone talking to them than for drivers not using cellphones.

``The human mind can multitask, but each task is performed with less brain power and lower proficiency,'' Just said.

The driving simulators also showed a deterioration of skills on the part of drivers who could hear someone talking to them, including weaving between lanes and edging over the side of the road.

``When someone is speaking your native language, you can't will yourself to not hear and process it. It just goes in,'' Just said. Even if a driver tries to ignore the words, scientists ``can see activation in the auditory cortex, in the language areas (of the brain). ``

Accident investigators have seen cases of drivers talking on hands-free phones whose minds are so engrossed in their conversations that they ran into something plainly visible.

In a 2004, a bus driver taking students on a class trip drove his 12-foot (3.6-meter)-high bus into a 10-foot, 2-inch (3.05-meter)-high bridge arch in suburban Alexandria, Virginia, peeling off the roof of the bus. There were signs warning drivers about the height of the bridge, and the bus driver was familiar with the route. He also saw a bus in front of him change lanes to avoid the low arch. But the bus driver, who was talking on a hands-free phone at the time, drove right into it.

``There is a standard code for crash investigations called roughly `look, but didn't see.' In other words, I was looking in the right place, but I didn't register what was there,'' Hedlund said.

Of course, drivers do not have to be using cellphones to have conversations _ they talk with passengers all the time. But talking to an adult passenger does not involve the same risk as a phone conversation, researchers said. That is because passengers are engaged in the driving experience with the driver. If they see a danger, they'll usually warn the driver. Passengers also tend to instinctually adjust their conversation to the level of traffic and other difficulties confronting the driver.

There are lots of other things that go on in cars that are risky: eating and drinking, tuning the radio, studying maps and applying makeup, for example. Just like talking on the phone, most of those things involve a choice by the driver.

As for the screaming toddler in the backseat demanding attention, ``some things are just part of life,'' McCartt said.___

 

<한글기사>

운전중 통화, 핸즈프리써도 위험천만



최근 운전 중 핸즈프리를 이용한 휴대전화 사용까지 금지 한 미국 연방교통안전위원회(NTSB)의 권고안을 놓고 찬반 논란이 일고 있지만, 핸즈프리를 쓰더라도 운전 중 통화는 여전히 위험하다는 연구 결과가 나왔다.

핸즈프리 이용 여부와 관계없이 운전 중 휴대전화를 사용하면 사용하지 않았을 때보다 사고 낼 확률은 4배나 높은 것으로 나타났다.

마르셀 저스트 미국 카네기 멜론대 인지두뇌영상센터 소장은 자기공명장치(MRI) 로 모의 실험한 결과 운전 중 누군가와 대화한 이는 휴대전화를 사용하지 않은 사람보다 운전에 37% 가량 주의를 덜 기울였다고 밝혔다.

실험 결과 일부 운전자는 운전 기술이 떨어져 심지어 차선을 넘나들고 도로  갓 길을 침범하기도 한 것으로 나타났다.

저스트 소장은 "운전 중 누군가가 당신에게 모국어로 말을 건다면 듣지 않을 재 간이 없다"면서 "인간 마음은 여러 일을 동시에 할 수 있고, 각각 일에 따라 지력이 배분되고 그에 따라 성과도 달라진다"고 말했다.

고속도로 관리청이 운전자 6천명을 대상으로 한 여론조사결과 40%는 운전중  핸 즈프리 휴대전화가 '안전하다'고 생각한 반면 일반 휴대전화가 '안전하다'고 생각하 는 이는 12%에도 미치지 않았다. 핸즈프리가 일반 전화보다 더 안전하다고 여기는 셈이다.

이처럼 핸즈프리 휴대전화는 일반 휴대전화보다 안전할 것 같으나 전문가들에 따르면 위험하기는 매한가지다. 둘다 주의를 분산시키는 정도가 비슷해 위험하다고 전문가들은 경고한다.

교통사고 조사관들은 핸즈프리 사용자가 대화에 정신을 빼앗겨 위험한 상황을 뻔히 보면서도 사고를 낸 경우를 여러차례 목격했다고 말했다.

지난 2004년 수학여행 버스 기사가 핸즈프리 휴대전화로 대화에 몰입해 익숙한 길이고 앞차가 차선을 변경한 것을 보고도 그대로 통과하려다 교량 상판에 버스 지붕이 뜯긴 사고를 냈다.

전국고속도로안전협회 짐 헤드룬드 안전담당관은 "사고 조사관 사이에 '봤는데 눈에 들어오지 않은' 경우로, 분명히 똑바로 봤는데 제대로 들어오지 않은 사례가 있다"고 말했다.

하지만 운전 경험이 있는 성인 동승자는 운전자에게 말을 건넬때도 전방에 주의 하며 운전자를 배려하기에 휴대전화 만큼 위험하지 않다고 조사관들은 전했다.