Drivers distracted by talking or texting on mobile phones killed an estimated 16,000 people from 2001 to 2007, US researchers have reported.
The estimate, one of the first scientific attempts to quantify how many people have died in accidents caused specifically by mobile telephone distractions, also suggests a growing number of these drivers are under 30.
"Our results suggested that recent and rapid increases in texting volumes have resulted in thousands of additional road fatalities in the United States," Fernando Wilson and Jim Stimpson of the University of North Texas Health Science Center wrote in the American Journal of Public Health.
Wilson and Stimpson used details on road deaths from each state, on mobile phone ownership and data on text message volume from the Federal Communications Commission.
They got reports from the National Highway Traffic Safety Administration on deaths attributable to distracted driving.
"Since roughly 2001-2002, texting volumes have increased by several hundred per cent," Wilson said in a telephone interview. In 2002, 1 million texts were sent every month; this rose to 110 million in 2008.
"Since 2001 our model predicts that about 16,000 people have died since then that we attribute to the increase in texting volume in the United States."
Just talking on a mobile phone can distract a driver, and several studies have demonstrated that, even with a hands-free device. But Wilson said texting and using so-called smart phones that provide e-mail access and other distracting applications take the problem to a new level.
US traffic deaths are down -- in 2009 the Transportation Department said they hit their lowest level since the mid-1950s in 2009 at 33,963.
But for every 1 million new mobile phone subscribers, Wilson and Stimpson estimate a 19-per cent rise in deaths due to distracted driving.
"Distracted deaths as a share of all road fatalities increased from 10.9 per cent to 15.8 per cent from 1999 to 2008, and much of the increase occurred after 2005," they wrote.
"In 2008, approximately 1 in 6 fatal vehicle collisions resulted from a driver being distracted while driving," the report said. It found 5,870 people died in accidents attributed to distracted driving.
Mobile phone ownership and the number of text messages sent rose sharply over the same time, Wilson and Stimpson found.
Wilson said 30 states ban texting while driving, and some cities and states require hands-free devices for drivers using mobile telephones.