Texting while driving is more dangerous than previously thought, new findings from a Texas study show.
Reading or writing a text message behind the wheel can drastically slow down a driver's reaction time, according to a study released Wednesday by the Texas Transportation Institute.
"Texting while driving basically doubles a driver's reaction time and makes the driver less able to respond to sudden roadway dangers, if a vehicle were to make a sudden stop in front of them or if a child was to run across the road," said researcher Christine Yager, who managed the study.
Reaction times slowed from one to two seconds with no texting, to three to four seconds while texting, the study found. The study also found very little difference in response times between a driver composing a message and a driver reading one.
"If you're on a freeway where the speed limit is 60 in rush hour and a vehicle suddenly stops in front of you, that's not enough time to react if your eyes are glanced down at your phone," Yager said.
Researchers studied 42 drivers between the ages of 16 and 54 on a test-track driving course.
Researchers said the study is the first published work in the U.S. to examine texting while driving in actual vehicles rather than in simulators, which have been used more frequently in previous studies for safety concerns.
Thirty-four states have adopted bans on texting while driving, according to the Governors Highway Safety Association. The Texas Legislature approved a texting ban earlier this year, but Gov. Rick Perry vetoed the measure, calling it an "overreach" and a "government effort to micromanage the behavior of adults."
Texas law does ban cellphone use in school zones and includes restrictions for drivers younger than 18.
In 2009, nearly 5,500 people died and half a million were injured in crashes involving a distracted driver, according to figures from the National Highway Traffic Safety Administration. Distraction-related fatalities represented 16 percent of overall traffic fatalities in 2009, the agency said. It's unclear how many of those fatalities can be blamed specifically on texting.
"If you look down to text for just a few seconds at 55 miles per hour, your car travels the length of a football field while you're not looking at the road," U.S. Transportation Secretary Ray LaHood said in a statement responding to the study. "Texting and talking on the phone while driving can be deadly, and drivers have a responsibility to put away these distracting devices every time they get behind the wheel."