Dr. Linda Hill of the University of California, San Diego, School of Medicine said studies showed phoning and driving increase the risk of crashes four-fold, with hands-free and handheld devices equally dangerous; this is the same as driving with a blood alcohol content at the legal limit of 0.08 percent.
"Texting increases this risk eight to 16 times," Hill said in a statement. "A key initiative for the Training, Research and Education for Driving Safety -- TREDS -- program and goal of the survey is to understand distracted driving behavior and work on strategies to improve road safety."
The California Highway Patrol said cellphone use while driving isn't the only issue.
"Anything from drinking coffee to managing children can take your mind off the road at a critical moment," John Antillon, CHP border division assistant chief, said.
The Adult Cell Phone Survey of U.S. adults ages 30-64 was conducted Feb. 8-March 31. Overall, 715 participants completed the survey: 75 percent female, two-thirds married with an average age was 46.
The survey also found of the 512 respondents driving an average of 1-2 hours per day, the reported use of cellphones for talking, texting and other applications was: 30 percent ranged from sometimes to frequently, 53 percent rarely and 17 percent never. Fifty-six percent reported driving with a handheld phone and 92 percent drive with a hands-free phone.
In addition, of the 261 respondents with children younger than age 11 in the car, 65 percent drive with a cellphone and 36 percent text.
Thirty-one percent of respondents said they felt obliged to take a work-related call while driving.
"Moreover, employers should be aware that encouraging workers to initiate and receive calls while driving on the job is putting their employees at risk and exposing their companies to potential liability," Hill said.
No margin of error was provided.