Police don't have data on number of lives saved by issuing speeding tickets, but say there's not just one method that contributes to safer roads.

New Zealand Police has no evidence on whether speeding tickets save lives, says United Future leader Peter Dunne.

But police argue there is well-documented research linking speed and road trauma.

Dunne asked police in an Official Information Act request for the estimated number of lives saved in the past two years due to speeding enforcement.

CHRIS SKELTON/FAIRFAX NZ United Future leader Peter Dunne was taken aback at the police response to his OIA request.

Police responded that the information did not exist.

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Dunne said the revelation will fuel "widespread" public opinion that the police approach to speeding focused on revenue gathering.

"I've long been suspicious of the policy and I thought it would be interesting to qualify what the impacts were - that was what led me to make the request," Dunne said.

"We live in an era where evidence-based policy is the norm. It doesn't appear that it applies in this case."

Dunne said there was an obvious connection between speed and accidents but the police needed to back up their claims about speed.

"Issues like vehicle design, road design, better education about the way we drive, don't seem to be getting nearly the same prominent focus that the speed issue is getting," he said.

Dunne recently admitted he had been slapped with two fines in one day for speeding down the same stretch of road.

POLICE: NO 'SINGLE INTERVENTION' TO SAVE LIVES

Police would be "delighted" if they didn't have to dish out fines, said National Manager Road Policing Superintendent Steve Greally.

All money from infringements goes to the Government, not police, he said.

However, road safety was not about any single intervention.

"The issuing of infringements through speed cameras and by officers is just one of the preventative measures taken by Police to reduce the mean speed of motorists on our roads," he said.

"Overall reductions in mean speeds have been shown to have a corresponding reduction in deaths and injuries.

"We know that in many instances issuing infringements encourages people to slow down and can prompt them to change their future behaviour – which could be the intervention that saves their life."

Speeding was a contributing factor in 78 fatal crashes and 357 serious injury crashes in 2014 - resulting in 84 deaths, Greally said.

Driving too fast for the conditions contributed to about a third of all fatal crashes.

"Speed cameras and officer enforcement have long been part of a range of safety tools used by Police to help bring down mean speeds and reduce trauma on our roads," he said.

​In the year 2014/15 there were nearly a million speed camera and officer-issued infringement notices, according to police figures.

That's $77 million worth of fines.

The previous year was similar - there were more than a million tickets, amounting to $78m.

The Police Minister did not respond to a request for comment.

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