Last month's road toll was the lowest since records began - but police are warning motorists not to become complacent, and to continue driving safely.
Provisional figures show 12 road deaths in April - the lowest for any month since 1965, when monthly records began.
The record-low April toll comes after New Zealand last year recorded its lowest annual road toll in 50 years, the previously lowest monthly figure of 16 deaths in February and the fatality-free holiday period over Easter.
Commentators believe a combination of the new give-way rules, high petrol prices, stricter road policing and improved driving behaviour have all contributed to the encouraging drop in fatalities.
National road policing manager Rob Morgan says the record-low toll is a result of long-term efforts to make roads safer.
"It's not just blind luck or randomness - there are things being done to make the roads safer and there's a whole lot of people working towards that all day, every day."
The Transport Agency, the Government and police were working together on ways of minimising deaths and injuries on the roads.
Increasing the minimum driving age to 16, the zero alcohol limit for teen drivers, tougher restricted licensing tests and more median barriers on highways were all part of the plan to keep reducing the toll.
"And I think it's about a whole bunch of road-safety conversations happening in people's homes and in the community," Mr Morgan said.
"People used to just get in their cars and drive, and if you were a bit of a larrikin it was seen as a bit of a laughing point. Now, if you're a bit of a larrikin, it's not socially acceptable. It's just good choices being made by people every day."
At the end of March, the death toll on the roads was 19 more than at the same time last year, and police were concerned about where the toll was going to go, Mr Morgan said.
But April's record-low figure meant the toll was on par with the 97 deaths at the same time last year.
"No one can get complacent ... Next month, we could just as easily be talking about an increase," Mr Morgan said.
Transport Agency spokesman Andy Knackstedt said what was even more pleasing than last month's low toll was the overall trend of fewer road deaths.
In 2010, 42 people died on the roads during April, against last month's 12.
That was 30 fewer families torn apart by a loved one's death, Mr Knackstedt said.
"It's too early to say what may or may not be responsible for the lower deaths over the course of one month.
"But we do know that over the long term, people are driving at speeds that are more appropriate to the conditions, that they're looking to buy themselves and their families safer vehicles, that the engineers who design the roads are certainly making a big effort to make roads and roadsides more forgiving so if a crash does take place it doesn't necessarily cost someone their life."
Drivers could take credit for behaving in a way that led to fewer crashes.
The high price of petrol was also helping motorists to drive more safely, Mr Knackstedt suggested.
"When you know that petrol's more expensive, you're less likely to speed because most people understand that driving at the speed limit is much more fuel efficient than exceeding it."
The Automobile Association's motoring affairs manager, Mike Noon, said April's record set a precedent.
He believed increased road-safety awareness and people behaving more cautiously on the roads, possibly as a result of the changed give-way rules, were reasons for the low toll.
"The naysayers said this [the rule changes] would result in carnage on our roads, but what we have seen and has been reported is that motorists are taking extra care at intersections and are being forgiving to others."
Mr Morgan and Mr Knackstedt said it was too early to know for sure whether the new give-way rules were a factor in last month's reduced toll.
"But when we speak to police they're certainly telling us that they're exhibiting better behaviour around intersections, in particular that people are generally being very patient, very cautious and very courteous and that can only be a good thing," Mr Knackstedt said.
The challenge now was to keep drivers vigilant about the rules over the next couple of months as the changes slowly became second nature.
Mr Morgan said that with Easter behind them, police were now planning for Queen's Birthday weekend.By Amelia Wade Email Amelia