The Transport Ministry has clarified the terms of a new law that restricts the use of cellphones in cars, saying that from November it will be illegal to use a mobile phone as a satellite navigation aid while driving. 2degrees chief executive Eric Hertz admitted rear-ending another vehicle at an intersection in Auckland a few weeks ago while glancing at directions on his iPhone, which was mounted on a hands-free kit in his car. Under the new law, that would be illegal, Transport Ministry spokesman John Summers confirmed. "The Road User Amendment Rule 2009 means drivers will not be able to look at a navigation aid on a mobile phone when driving, even if it is mounted on the dashboard. "You can use a mobile phone held in a cradle while driving, but only to make, receive or terminate a phone call. You cannot use them in any other way, such as reading a GPS map, reading email or consulting an electronic diary." The restriction does not apply to navigation systems that do not have a mobile phone function, he says. Mr Hertz expressed surprise at a media report that claimed the other vehicle involved in the accident had been a write-off and that its driver had suffered back injuries requiring weeks off work. He was not aware of any injuries and the crash was not reported to police. "We had a chat and exchanged licence plate numbers and insurance details. We both drove off. It was, from my perspective, a relatively minor fender-bender."