Put Down That Cell Phone When Driving

Cell phone use or distraction greatly increased odds for accidents

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) New drivers are more likely to be in a car crash, and distractions have been shown to play a role. Near-crashes and incidents with experienced drivers may help tell the rest of the story.

To examine the role of distraction in car crashes and to see if there was a difference in new versus experienced drivers, researchers used sensors and tracking devices installed in the cars of new and experienced drivers to determine what happened just before crashes and near-crashes occurred.

These researchers found that, even though distracting tasks were performed at the same rate by new and experienced drivers, new drivers had increased risks of crashing or nearly-crashing from using a cell phone, reaching for an object, eating or looking at something on the roadside.

"Keep eyes on the road and not on your phone."

This research team was led by Sheila G. Klauer, PhD, from the Virginia Tech Transportation Institute, and Feng Guo, PhD, from the Virginia Tech Transportation Institute and the Department of Statistics at Virginia Polytechnic Institute and State University in Blacksburg, VA.

These researchers used data from two previously conducted studies. One study, called 100-Car Naturalistic Driving Study (the 100 Car Study), collected driving data from 2003 through July 2004. The other study was called the Naturalistic Teenage Driving Study (NTDS) and collected data from June 2006 through September 2008.

A total of 151 people participated in the two studies — 42 new drivers in the NTDS and 109 experienced adult drivers in the 100 Car Study.

The new drivers group was made up of 20 males and 22 females, with an average age of 16.4 years. This group had had a driver’s license for three weeks or less. The adult driver 100 Car Study group was made up of 66 men and 43 women, with an average age of 36.2 years. Participants in this group had been driving for an average of 20 years.

To accumulate data on driving experiences, these researchers used recording devices in the vehicles. They installed four cameras that tracked each driver's forward view, rear view, view over the driver’s right shoulder and a view of the driver’s face. They also installed sensors, including forward radar, GPS systems, machine-vision lane trackers and accelerometers in the cars of study participants.

The research team used standardized definitions of a crash and a near-crash. Their definition of a crash was when the operator’s vehicle came in physical contact with another vehicle or object. The driver had to be at fault or partly at fault for the accident. The researchers defined a near-crash as any situation that needed the driver to make a last minute maneuver that “challenged the physical limitations of the vehicle."

Any accidents in which drivers were not at fault were excluded from the study data. There were 108 of these accidents in the NTDS group and 190 of them in the 100 Car study. Accidents in which the driver was sleepy or may have been under the influence of alcohol or drugs were also excluded. In the 100 Car Study group, 113 events met this definition and were excluded from the study data. There were seven events meeting this definition in the NTDS group and they were also excluded.

The number of driving events that were included in the research from the NTDS group was 136 near-crashes and 31 crashes. Experienced drivers in the 100 Car Study had 476 near-crashes and 46 crashes that were included in this study.

Of all the crashes included in this study, none involved serious injury or death of the participants.

The researchers used a list of secondary tasks and calculated the chance that they were associated with a crash or near-crash. Secondary tasks included using a cell phone, reaching for objects, eating, drinking, adjusting controls and looking at roadside objects.

Dr. Klauer and colleagues found that new and experienced drivers performed secondary tasks at the same rates. They were performed by 9.9 percent of new drivers and 10.9 percent of experienced drivers.

Only dialing a cell phone increased the risk of crash or near-crash among experienced drivers, with 2.5 times increased odds.

Dialing a cell phone was associated with an 8.3 times increased risk of crash or near-crash among new drivers. Reaching for a phone was associated with a seven-fold increase in risk and reaching for another object increased risk eight-fold. Texting was associated with a 3.9-fold increase in risk.

Eating while driving increased the odds of crash or near-crash among new drivers by three-fold, and drinking was associated with a 1.4 times greater risk.

Adjusting the radio or temperature controls was associated with a 1.4 times increased risk, and adjusting controls other than radio or temperature was associated with a 2.6 times increased risk in new drivers.

Looking at a roadside object, including other car accidents, increased the odds of crash or near-crash 3.9-fold among new drivers.

Interestingly, talking on a cell phone was associated with a 40 percent decreased risk in new drivers and a 25 percent decreased risk for experienced drivers compared to when they were not talking on the phone.

All secondary tasks in this study required drivers to distract their focus from the road, and the frequency of these tasks increased over the 18-month study period.

Dr. Klauer summarized the research by stating, “Novice drivers are more likely to engage in high-risk secondary tasks more frequently over time as they became more comfortable with driving. The increasingly high rates of secondary task engagement among newly licensed novice drivers in our study are worrisome as this appears to be an important contributing factor to crashes or near-crashes.”

She continued “Any secondary task that takes the novice driver’s eyes off the road increases risk. A distracted driver is unable to recognize and respond to road hazards, such as the abrupt slowing of a lead vehicle or the sudden entrance of a vehicle, pedestrian, or object onto the forward roadway.”

The researchers cited several limitations of their study. The number of drivers and crashes was relatively small and included people from one geographic region. Measurements of crash and near-crash data were similar, but not identical, in the two studies and interpretation was done by qualified professionals, but some determinations were based on interpretation of the experts. Additionally, in both the 100 Car Study and the NTDS study, most of the events were near-crashes, not crashes.

This research was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Highway Traffic Safety Administration.

This article was published in the January issue of The New England Journal of Medicine.

Reviewed by: 
Review Date: 
January 3, 2014
Last Updated:
January 4, 2014