You may be surprised. When we think of distracted drivers, we often picture a teenager texting while driving, or perhaps someone eating in the car. When a major insurance company looked carefully at the issue recently, however, it discovered that one distracted driving behavior was involved in a whopping 62 percent of the accidents it studied. By contrast, texting and cell phone use together were the cause of only 12 percent.

The No. 1 driving distraction that causes serious or fatal car accidents in the U.S.? Daydreaming.

“Distracted driving is any activity that takes your eyes off the road, your hands off the wheel, or your mind off your primary task of driving safely,” explained the senior vice president of personal lines at the insurer. Daydreaming or being lost in thought is apparently very distracting indeed.

The study analyzed police reports connected to the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System, which collects data on fatal motor vehicle accidents nationwide. Carefully examining the stated cause of each distracted driving accident from 2010 and 2011, researchers found that police officers listed “generally distracted,” “lost in thought” or “daydreaming” as the cause in nearly two-thirds of the fatal accidents.

The other nine top distracted driving behaviors blamed for car accidents are:

•  Texting or cell phone use (12 percent)
•  Rubbernecking, or paying attention to something
   outside the car (7 percent)
•  Talking to or looking at other vehicle occupants (5 percent)
•  Using or reaching for a device in the vehicle, such
   as headphones or a GPS device (2 percent)
•  Eating or drinking (2 percent)
•  Using equipment integrated into the vehicle, such as adjusting
   mirrors or seats (1 percent)
•  A pet or other moving object inside the vehicle (1 percent)
•  Smoking-related distractions (1 percent)

Source: Insurance Journal, “Insurer Analyzes Top 10 Driving Distractions Involved in Fatal Car Crashes,” April 4, 2013