Hands free mobiles was once thought to be safe but has now paved way for apprehensions.

A study of Australian drivers found that those using cellphones were four times as likely to be involved in serious crashes, regardless of whether they used hands-free devices like earpieces or speaker phones that have been said to make talking while driving safer.

Hands-free phones have been available since the mid-1990s. Most of these devices are connected by a wire to a cell phone. Few wireless models use short-wave radio technology to exchange signals with the host phone.

There are three basic styles for hands-free phones: a headphone with a foam ear piece; a device that fits over the ear; and an "ear bud" that fits inside the ear.

Few researchers feel the devices may actually put people at greater risk than hand-held ones.However some are of the view that hands free devices are safer under very limited circumstances.