Truck drivers are 23 times as likely to run the risk of a crash while texting than when they are otherwise not distracted, suggests a new U.S. study.

Truck drivers in the study spent an average of 4.6 seconds looking at their devices instead of the road ahead before 'safety-critical events,' say the Virginia Tech researchers. (Jae C. Hong/Associated Press)

The study's results, published Tuesday by the Virginia Tech Transportation Institute, observed U.S. light vehicle drivers and truckers for more than 9.5 million kilometres through video cameras installed in their vehicles. The data is in the process of being peer reviewed before formal publication.

The study examined drivers' use of cellphones and other mobile devices while driving over 18 months. It found that among truck drivers, their risk of being involved in safety-critical event — or risk of collision — was 23.2 times greater when they were texting than when they were not distracted.

The study also found that right before a crash threat or near collision, truck drivers sending text messages had spent an average of 4.6 seconds looking at their devices. Assuming the driver is travelling at 90 km/h (or 55 m.p.h., a common U.S. speed limit), he or she would cover around the length of a football field in that time.

While the study did not measure texting among drivers of smaller vehicles and cars, the risk of a crash was elevated significantly for all drivers while dialling a cellphone. And truck drivers reaching for a cellphone were 6.7 times more likely to be involved in a crash than when otherwise not distracted.

The authors noted that among all drivers using cellphones, the risk of a crash or a near-crash was lower for drivers of small vehicles and cars compared to truckers.

Lab studies criticized

The study found that the risk of crash among drivers of small vehicles who talked or listened on cellphones increased 1.3 times. The risk among truckers however, did not increase at all.

In light of those findings, the authors dispute recent research that suggests talking and listening on cellphones is just as dangerous as visually distracting cellphone tasks like texting, dialling or reaching for a mobile device. The Virginia Tech researchers say that studies that use laboratory simulations — some of which have compared the risks of cellphone use to those incurred while driving drunk — don't do a good enough job of replicating on-road conditions.

"Recent comparisons made in the literature greatly exaggerate the cellphone risk relative to the very serious effects of alcohol use, which increases the risk of a fatal crash approximately seven times that of sober driving," the authors said in a release.

"Using simple fatal crash and phone use statistics, if talking on cellphones was as risky as driving while drunk, the number of fatal crashes would have increased roughly 50 per cent in the last decade instead of remaining largely unchanged."

The researchers say the key conclusion to be drawn from the study is that keeping eyes on the road is the best way to ensure road safety.

The study also concluded that headset cellphone use is not substantially safer than hand-held because the primary risks associated with both are answering, dialling, and other tasks that take drivers' eyes off the road.

The researchers recommend that texting be banned for all drivers, and all cellphone use should be prohibited for newly licensed teen drivers.

There are number of restrictions on cellphone use in Canada. Newfoundland and Labrador, Nova Scotia and Quebec all restrict cellphone use while driving. Ontario passed legislation in April enacting a cellphone ban, which will take effect in October.