New high-tech speed cameras will be tested at Auckland's Waterview Tunnel and on a section of the Southern Motorway before the Government decides whether to roll them out around the country.
The year-long trial of point-to-point cameras will begin around the middle of next year and, although they are only trials, tickets will still be issued to motorists who speed.
Police Minister Stuart Nash said the cameras would be an incentive to motorists to drive at safe speeds.
"The intention is to stop people who are unnecessarily putting other people at risk by driving at an unsafe speed over a sustained distance.
"Overseas evidence has shown that average speed cameras are highly effective at reducing speeds, and generally result in fewer tickets being issued compared with single location speed cameras," Nash said.
Acting Associate Transport Minister James Shaw said the locations, at Waterview Tunnel and the section of Southern Motorway between the SH20/SH1 connection at Manukau and Papakura, were chosen because they were sites where high-speed crashes could be deadly.
Motorists will not be ticketed for speeding for just a few seconds but only if their average speed over the distance between two cameras, one at each end of the stretch of road, exceeds the limit.
Fines will be the same as those for current spot speeding infringements and will not include demerit points.
The AA welcomed the trial.
"Average speed cameras are used in many other countries so it makes sense for us to trial them here in New Zealand," said AA principal adviser regulations Mark Stockdale.
"If they can help us to get more people travelling at safe speeds and less tickets being issued that will be a win-win for everyone."
A survey of AA members found the majority supported the idea of average speed cameras, he said.
"Overseas experience is that average speed cameras are better at keeping speeds down over wider areas than traditional cameras.
"Importantly, they also had much lower ticketing rates as they are focused on catching people who are consistently above the limit."
In addition to the point-to-point camera trial, the New Zealand Transport Agency will test two new speed camera warning signs that alert drivers before they enter high-risk zones.
The six-month trial will start next month at eight sites around Auckland and will test whether the signs are effective at encouraging drivers to stay within the speed limit.
"These warning signs are about giving people a fair chance to slow down on high-risk roads and avoid a ticket. Ultimately, we'd like to see more people slowing down and fewer tickets issued," Shaw said.
Vehicle speeds are being measured at the sites ahead of the signs' installation and the data will be compared with speeds measured during the trial to assess the effectiveness of the different signs.
Motorists using the Waterview Tunnel forked out over $2.5 million in speeding fines over the first eight months the tunnel was open.
Figures released to the Herald under the Official Information Act showed 29,047 speed-camera notices were issued to drivers between July 4 2017 and March 7 2018.
The total value was $2,579,490 and included 19 summonable offences, which did not contribute to the monetary figure.
Police operate four speed cameras in the tunnel area, with one at each entrance and exit to the tunnel.
How point to point cameras work
Time-stamped images of vehicles are taken on a stretch of road, one as they enter and another as they exit.
The vehicles are identified using number plate recognition software.
Software determines if the vehicle was speeding by dividing the distance between the start and finish points by the time taken to travel the distance.
A fine is sent to the motorist.