Using a virtual reality environment, U.S. researchers have seen for themselves just how dangerous it can be for children to cross the street while talking on a cellphone.

The research team from the University of Alabama at Birmingham reported Monday that children who talked on cellphones as pedestrians in this virtual world were 43 per cent more likely to be hit by a vehicle or have a close call than when their phones were turned off.

In addition, the children who were distracted with the gadgets looked both ways 20 per cent fewer times before crossing the street and gave themselves eight per cent less time to cross safely in front of oncoming traffic when they were talking on the phone.

The researchers found that all of the children – even those who were experienced with talking on cellphones or rated as highly attentive – were more likely to exhibit risky behaviours when they crossed the virtual street while distracted.

“Cellphones clearly offer convenience and safeguards to families, but they also may pose risk,” they said, “particularly when children attempt to multitask while conversing on the cellphone and have reduced cognitive capacity to devote to potentially dangerous activities such as crossing streets.”

The study looked at 77 participants age 10 to 11 — the age when most children are just starting to cross streets without adult supervision.

There was no difference in behaviour between boys and girls in the study group.

The researchers noted that crossing streets is a "highly complex cognitive and perceptual task." Children around the ages of the subjects in the study group may not have developed the cognitive skills necessary to simultaneously perceive and process the speed at which they can cover the distance from one side of the street to the other.

Those taking part in the study were first allowed to familiarize themselves with the street scene before starting the test. They were then asked to run through the simulation 12 times, six while undistracted and six while they talked on the phone with an unfamiliar research assistant.

Traffic was shown to move in two directions on three monitors arranged in a semi-circle in front of the participant to display an actual Birmingham-area crosswalk with simulated vehicles of different sizes. Ambient and traffic noise was delivered through speakers.

The virtual vehicles travelled at a constant speed of just under 50 km/h and appeared at an average distance between them of 160 metres.

The researchers asked the children to cross the street when they believed it was safe. The children stepped from the “curb,” onto a pad with a pressure switch electronically connected to a computer, and the system registered the precise moment they entered the “street.”

The results of the study appear in the February issue of the journal Pediatrics.

The study listed a few limitations, including a fairly small sample group that was narrow in age range and recruited from one geographical location.

In addition, the distracting phone call, while friendly, was from an adult the children had never met.

Traffic flow matched that of the suburbs, not an urban setting, and only one street environment was used.