Driver inattention is the leading factor in most crashes and near-crashes, according to a research report released Thursday, April 20, by the National Highway Traffic Safety Administration.

According to the study, which was conducted by NHTSA and the Virginia Tech Transportation Institute, nearly 80 percent of crashes and 65 percent of near-crashes involved some form of driver inattention within three seconds before the event. The primary causes of driver inattention were drowsiness and distracting activities, such as cell phone use.

“This important research illustrates the potentially dire consequences that can occur while driving distracted or drowsy. It’s crucial that drivers always be alert when on the road,” said Jacqueline Glassman, acting administrator of NHTSA, at a press conference.

The “100-Car Naturalistic Driving Study” tracked the behavior of the drivers of 100 vehicles equipped with video and sensor devices for more than one year. During that time, the vehicles were driven nearly 2 million miles, yielding 42,300 hours of data. The 241 drivers of the vehicles were involved in 82 crashes, 761 near-crashes and 8,295 critical incidents.

In addition, a follow-up analysis to the 100-Car Study has also been released. Focused on the types of driver inattention and their associated risk, key findings include:

• Drowsiness is a significant problem that increases a driver’s risk of a crash or near-crash by at least a factor of four. But drowsy driving may be significantly under-reported in police crash investigations.
• The most common distraction for drivers is the use of cell phones. However, the number of crashes and near-crashes attributable to dialing is nearly identical to the number associated with talking or listening. Dialing is more dangerous but occurs less often than talking or listening.
• Reaching for a moving object increased the risk of a crash or near-crash by 9 times; looking at an external object by 3.7 times; reading by 3 times; applying makeup by 3 times; dialing a hand-held device – typically a cell phone – by almost 3 times; and talking or listening on a hand-held device by 1.3 times.
• Drivers who engage frequently in distracting activities are more likely to be involved in an inattention-related crash or near-crash. However, drivers are often unable to predict when it is safe to look away from the road to multi-task because the situation can change abruptly, leaving the driver no time to react even when looking away from the forward roadway for only a brief time.