Cape Town motorists caught talking or texting on their cellphones will be fined R500 and have their phones confiscated for a day, the city said on Monday.
Safety and security mayoral committee member JP Smith hoped these measures would "help people get the message" and improve road safety.
He said the new bylaw, in effect from Monday, formed part of the provincial road safety campaign to halve road deaths by 2014.
According to the Cape Times, Cape Town was the only city in South Africa where the road death toll was steadily decreasing, from 1739 deaths in 2008 to 1321 in 2011.
Confiscated cellphones could be collected at the Gallows Hill Traffic Department, in Green Point, after 24 hours. Motorists would have to show their identity documents.
"Phones will be placed in very secure containers, which have a double seal [and serial number]. The box will be sealed and opened in front of the motorist," Smith said.
The centre was a 24-hour facility, so impoundments over weekends would not be delayed.
"We're hoping we don't have to confiscate any phones. We're losing a lot of money through the additional administrative tasks. It's the officers' time, the admin personnel that have to be assigned to this duty."
Smith said impoundment fees would probably be introduced in a year, to offset the administrative costs.