Researchers compiled their numbers after observing 7,800 motorists at intersections in six counties. The study found that nearly half of drivers using electronic devices were observed texting.
Dr. Beth Ebel, the study's principal investigator, said the findings suggest distracted driving is more common than previously thought. She was surprised by how many were taking their eyes off the road to text.
"The risk of crash with texting is so high," Ebel said. "It really makes you impaired."
Ebel noted that other studies have shown that texting while driving increases the risk of crash dramatically, similar to having a blood-alcohol level of 0.19 percent.
The study is part of broader research designed to help public officials gauge whether they are making progress in strategies designed to deter distracted driving. Drivers who text while driving in Washington state could face a $124 fine.
Ebel said the new numbers may help state residents and policymakers have a discussion about making laws simpler and easier to enforce. Washington drivers currently may be able to bypass a ban on using a cellphone while driving, for example, by placing using speakerphone and holding the device away from the ear. Oregon's law is more stringent and straightforward, Ebel said.
Washington State Patrol Chief John Batiste said in a statement that the findings provide support to the believe that texting contributes to more collisions than law enforcement officers can prove.
"After a collision, drivers almost never admit they were texting," Batiste said. "We believe the problem has, until now, been drastically underreported."
Of the drivers identified as using an electronic device in the UW study, 45 percent were seen texting. Another 21 percent were talking on the phone with the device held at their ear. A similar number of people were talking into a phone in front of them, apparently using the speakerphone feature to avoid putting the phone to the ear in violation of Washington law. About 13 percent of device users had a visible hands-free device.