Daydreaming or being "lost in thought" is responsible for more fatal U.S. car crashes than mobile-phone use, a new study says.

Daydreaming or being lost in thought was the distraction 62 percent of the time, compared with 12 percent for mobile-phone use, according to a data study by Erie Insurance Group.

Erie called study results "disturbing."

ERIE, Pennsylvania — Daydreaming or being "lost in thought" is responsible for more fatal U.S. car crashes than mobile-phone use, a new insurance company study says.

Daydreaming or being lost in thought was the distraction 62 percent of the time, compared with 12 percent for mobile-phone use, according to the study by Erie Insurance Group.

"The results were disturbing," said Doug Smith, senior vice president of personal lines at Erie.

The study was based on police data from 2010 and 2011 from the National Highway Traffic Safety Administration's Fatality Analysis Reporting System. It showed "police listed the majority of drivers who were distracted as 'generally distracted' or 'lost in thought,'" the study noted.

"Rubbernecking" or looking at an outside person, object or event was cited as the No. 3 cause of distracted driving. Eating or drinking in a car was also cited as a cause of distracted driving, along with a moving object in the vehicle, such as a "pet or insect."

April is National Distracted-Driving Awareness Month. The insurer says distracted driving is defined as "any activity that takes your eyes off the road, your hands off the wheel or your mind off your primary task of driving safely."

Edmunds says: A big push is on to make motorists aware of high-risk behaviors when it comes to distracted driving.