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While it is no secret that operating a cell phone behind the wheel can be dangerous, it is often thought that there is less risk if drivers use a hands-free cell phone．New research shows that driving using a hands-free cell phone is just as risky as using a handheld cell phone．In fact, it is comparable to drunk driving!
Researchers from the University of Utah have found that drivers who use both handheld and hands-free cell phones are as distracted(分心)as drunk drivers．According to the research, drivers who use cell phones are more likely to delay braking and get into accidents．
In the study, 40 participants used the driving simulator(模拟器), PatrolSim, to test four different driving conditions：not distracted, using a handheld cell phone, using a hands-free cell phone, and drunk．The driving simulator followed another car that braked occasionally to test the participant’s reaction levels．During the drunk driving trial, the participants were instructed to drink vodka and orange juice until their blood alcohol level reached 0.08－the minimum level that defines drunk driving in most of the U．S．
The researchers found that the participants who talked on a handheld or hands-free cell phone drove slightly slower, had a 9％slower reaction time when stepping on the brakes, and had a 19％slower reaction time when resuming(恢复)normal speed after braking．And the participants who were drunk hit the brakes only 4 seconds before a collision(碰撞)could occur and hit the brakes with 23％more force．
The study also supports earlier research by the scientists, which found that hands-free cell phones were not less distracting than handheld cell phones．The distraction and danger appear to come not from the technology used but from the conversation itself．
1．What kind of driving is often wrongly thought to be the least risky?(回答词数不超过8个)
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2．Why are drivers using cell phones likely to delay braking and get into accidents?(回答词数不超过10个)
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3．What is the advice given in the passage?(回答词数不超过14个)
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