Auckland Transport wants motorists to put people's lives first when they consider new plans to reduce speeds across 10 percent of the city's roads.
Public consultation begins tomorrow on plans to cut the speed limit to 30km/h in the CBD and some town centres and reduce it to 60km/h on some rural roads.
Auckland Transport chief executive Shane Ellison said that was because research shows that cutting speed saved lives.
The extra time it would put on traffic was not worth lives, he said.
"Our analysis and modelling shows that that impact would be negligible," he said.
"In fact, we encourage people to ask themselves the question, 'is a small additional amount of travel time, really that much to tolerate in terms of saving people's lives?'"
Auckland Transport chair Lester Levy said motorists needed to take responsibility.
"We cannot let complacency trump safety, we have to work to get people to understand that nobody should be going out on our roads and getting killed," he said.
"It doesn't have to happen."
But the AA said the proposal went too far and would frustrate drivers.
Its spokesperson Barney Irvine said a recent survey of 14,000 Auckland members showed only 16 percent favour a 30km/h limit in the central city.
It was calling for a 40km/h limit instead, which Mr Irvine said was in line with the Transport Agency's recommendations and the current speed limit along Ponsonby Road.
"There are different views on this but certainly the most up to date credible research we've seen suggests that a 40km/h limit would achieve the right safety outcomes," he said.
"We think that our members and the public would certainly be more comfortable with that than they would be with 30km/h.
But that was still too fast for Auckland Transport, who said their research showed that risk of harm was significantly reduced when cars were driving 10km/h slower.
Pukekohe locals RNZ spoke to were divided with some unsure if reducing the speed would stop accidents while others calling for even slower speeds.
Aucklanders have until the end of March to provide feedback on its plan, which if adopted would come into force in August at a cost of $24million.