Any task that involves a driver’s hands and eyes has the highest risk of resulting in an incident or unsafe event on the road, according to study findings by the Virginia Tech Transportation Institute.

Many of these types of tasks involved hand-held electronics, said Susan Soccolich, a VTTI research associate for the institute’s division of freight, transit and heavy vehicle safety, during a presentation at the Fleet Safety Conference in California on Nov. 11.

 For example, the following tasks increase the risk of an unsafe event:

• texting on a cell phone: 23 times the risk

• interacting with a dispatching device: 10 times the risk

• dialing on a cell phone: 6 times on the risk

VTTI’s study, “Analysis of Naturalistic Driving Data to Assess Distraction and Drowsiness in Drivers of Commercial Motor Vehicles,” showed the longer a truck driver’s eyes were off the forward roadway, the greater the risk of being involved in a safety critical event. There was a significant increase once the driver’s eyes were off the road for more than two seconds.

Drivers who were browsing on a cell phone had one of the highest average times their eyes were off the roadway (four seconds). Drivers who were texting had their eyes off the road for an average of five seconds.

The study found that talking/listening on a hand-held phone (the most common cell phone use behavior) showed no change in risk while talking/listening on a hands-free device showed a reduced risk of being involved in a safety critical event. The study collected data over 3.8 million driving miles from various heavy-duty truck fleets.

Risk of Truck Driver Cell Phone Use

When a driver was perceived to be at-fault during a safety critical event, over 5% of drivers were browsing on a cell phone.

“What’s interesting about this study is what we’re not seeing as much as we used to,” Soccolich said.

Texting on a hand-held phone was one of the most infrequent types of cell phone use in the study. About 1% of drivers texted or were involved in a safety critical event.

“These drivers are browsing, and they’re talking and listening, as the regulations allow,” she said. “But they’re not texting in the way we may think based on how people behave in their everyday life.”

Hand-held cell phone tasks greatly increase the risk of safety critical events on the road. When the driver is perceived to be at-fault for the incident, these tasks increase the risk by four times.

Hands-free cell phone tasks cut the risk of these incidents in half. These drivers are involved in about as half as many events, Soccolich said.

The types of tasks impact the risk levels. See chart below. An odds ratio above 1 indicates an increased risk, while an odds ratio below 1 indicates no change in the risk.