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Wednesday, January 09, 2008
Cell Phone Users Lengthen Commute For Everyone
If you're late for work, it might be because a fellow driver on the road was using a cell phone. According to U.S. researchers, motorists who use cell phones while driving obstruct the flow of traffic, choke highways and lengthen commute times.
"It's a bit like breaking wind in the elevator,” said Peter Martin of the University of Utah's Traffic Lab in a telephone interview. “Everyone suffers."
Earlier studies have likened the risk of driving while talking on a cell phone with driving while drunk. There are 50 countries that have banned use of hand-held phones while driving.
The impact of cell phone use on traffic patterns is proven in the latest study. "It has to do with the reaction to changes in speed," said Martin, a civil and environmental engineering teacher.
"When a driver who is not distracted is in a traffic stream and the vehicle in front slows down, the driver will brake in response,” he said. “When a vehicle speeds up in front, the driver will respond and speed up."
A team of researchers helped Martin devise a study involving 36 university students, each driving through six 9.2 mile-long freeway scenarios in low- to high-density traffic at speeds that simulated driving on an interstate highway.
The drivers made calls on a hands-free phone during half their trips and did not use the phone during the other half. They were instructed to obey posted speed limits and use turn signals, but they were to make the rest of the driving decisions on their own.
What Martin and the researchers discovered is that when the drivers were interrupted by a phone conversation, they completed fewer lane changes, drove slower and took longer to get to their destination.
In medium- and high-concentrated traffic, drivers were about 20 percent less likely to change lanes. They also spent about 25 to 50 seconds longer driving behind slow-moving vehicles before moving to an open lane. And they drove about 2 mph (3.2 kph) slower than the undistracted drivers, and took 15 to 19 seconds longer to finish the 9.2 mile trip.
These accommodations might make driving safer for undistracted drivers. "But if you are doing that so you can take your mind off the road and talk on the phone, that isn't safer," said the team’s leader, University of Utah psychology professor Dave Strayer.
Particularly in light of studies that suggest as many as 10 percent of U.S. drivers are using a cell phone at any one time, those delays can add up.
"Delays in traffic streams of very small amounts grow into massive numbers when you project it across a highway and across a nation," Martin added.
The next stage is to employ computer models to understand just how much those delays are costing drivers in time and extra fuel costs resulting from traffic delays.
"What we've done here indicates already that those numbers are likely to be significant," Martin said.
For more information about driver safety, The National Safety Commission and Lowest Price Traffic School offer safe teen driving resources for new drivers and their parents.