A two-month anti-speeding campaign allowing drivers to travel no more than 4 km/h above the speed limit ends on Friday and police say initial results show it was successful.
Police usually ticket drivers at 10 km/h over the limit. The lower tolerance was enforced throughout December and January, the first time this had been done.
National road policing manager Superintendent Carey Griffiths said initial results show it was successful.
Mr Griffiths says 42 people have died since the beginning of December last year, 20 percent fewer than the 56 people who had died in road crashes during the same period the year before.
It will be three months before data is available for police to analyse how average speeds affected the result and how many injuries there were, he says.