The presence of squabbling children in the car has been found to reduce driver's reaction times by 13 per cent, reveals an in-depth study by Direct Line, commissioned with TRL (Transport Research Laboratory).

This slower reaction time indicates that people driving while children are arguing in the car would see an increase of four metres in their stopping distance when driving at a speed of 70mph. This increase in distance travelled is equivalent to the additional stopping distance travelled when driving with a blood alcohol level at the UK legal limit (80mg/100ml).

The noise of children arguing in the backseat of the car proved to be such a distraction to drivers' concentration that there was a 40 per cent increase in instances of hard brakingdue to lack of concentration, during the observational study. The studied motorists were also less able to maintain a constant speed or distance behind the car in front, when driving while listening to arguing children.

In addition to delayed reaction times, the motorists' stress levels were also found to increase by almost a third (28 per cent) while driving with arguing children in the car. Worryingly, previous research has established that stress is a factor associated with an increased risk of collisions****, further impacting families' road safety when the children are arguing in the car.

When the participants were interviewed following the study drive they reported that they felt more stressed, distracted, less confident, less safe and lacked concentration when they were driving while listening to squabbling children.

However, despite admitting that they felt that the noise of arguing children impaired their driving, the study found that the motorists did not reduce their speed to take this distraction into account during the observed drives.

Andy Goldby, motoring expert at Direct Line, commented: "This study indicates that many parents, child carers and indeed anyone who drives with children in the car are in a vulnerable position when the children are causing a distraction to their concentration.

There is no easy solution to prevent being instinctively distracted by children arguing or playing boisterously when you're behind the wheel, so Direct Line's advice is to ensure you're as prepared as possible in advance of a car journey to mitigate the kids' boredom and squabbling. Simple distractions can include providing in-car games and stopping frequently for fresh air and refreshments."

Dr Nick Reed, senior human factors researcher, TRL, added: "This study showed that there was a noticeable impairment to driving caused simply by the noise of arguing children. Consequently, drivers should be aware of such risks when setting out on long journeys with children. Where possible, precautions should be taken to minimise such distraction. Rest breaks not only provide an opportunity for refreshment and entertainment but also for the driver to catch up on any mobile phone calls or text messages that they may have missed whilst driving."