Motorists talking on a hands-free mobile phone can be significantly distracted, leading to slower reaction times and a failure to see possible hazards, according to a study commissioned for the British department of health.
Researchers found that talking on a phone is more distracting than speaking to a passenger or listening to, or changing, radio stations.
Key driving skills such as attention to road signs and other vehicles and decision making are impaired when talking on a mobile, researchers at the UK-based Transport Research Laboratory (TRL) found.
In Ireland and Britain, drivers are prohibited from using a mobile phone handset, but hands-free kits are permitted. According to the researchers, this may erroneously suggest to drivers that hands-free sets are safe.
Drivers caught holding a mobile phone while driving face a fixed charge of €60 and two penalty points. If a motorist challenges this charge in court the maximum penalty rises to four penalty points and a fine of up to €2,000.
The only defence is where the hand-held phone can be shown to have been used to contact the emergency services. Cradling a phone between neck and ear is also banned. More than 1,000 motorists a month are being caught using a mobile phone while driving, and incurring penalty points.
The report suggests that any mobile phone use by drivers may have to be banned and recommends further research into the different hands-free systems, adding that many need to be banned or have their use restricted under law.
"This study demonstrates that driving and talking is cognitively demanding, and results in poorer driving performance, supporting the conclusion of other research that this activity is likely to reduce safety."
It also suggests that this could also have implications for employers who contact staff on their hands-free phone while driving for work.
The researchers monitored 30 volunteers as they completed an 11-mile route in a driving simulator. The level of distraction caused by using a hands-free kit was compared to other conventional in-car tasks such as using the radio and talking to a passenger. They were compared to drivers who had no distractions while completing the route.
The results clearly showed that motorists using a hands-free kit were found to be more likely to have an inconsistent speed and to miss road signs. The study also showed that their ability to communicate was much lower than when talking to a passenger.
While the new Rules of the Road is explicit about drivers or motorcyclists not using a hand-held mobile phone, and recommends that cyclists also should not use them while cycling, it offers no guidance on hands-free kits.
The British Highway Code states that all mobile phone use by drivers is distracting, and should be avoided while driving.
The TRL study is the latest in a series of recent studies examining the level of distraction caused by the now ubiquitous mobile phone.
Researchers from the University of Utah found that using a hands-free mobile phone kit when driving causes the same level of impairment as being over the alcohol limit.
In this study, drivers using a mobile phone or hands-free kit were found to be five times more likely to crash than an undistracted driver.
The research team in this study suggested that the results "call into question driving regulations that prohibit hand-held cell phones and permit hands-free cell phones".
