Official figures show police are abandoning more road pursuits, but reveal a long-term trend of more deaths when pursuits end in crashes.
Thirty-six road deaths were linked to police pursuits from 2009 until mid-August this year, according to figures obtained under the Official Information Act.
From 2003 to 2008, 24 deaths occurred after chases, and in the previous six years, from 1997 to 2002, six road deaths were linked with police pursuits.
The figures also show police are abandoning more pursuits.
Last year, 53.1 percent of chases were abandoned compared to just over 37.6 percent in 2010.
But the number of pursuits that led to crashes rose to 418 last year, from 349 in 2010.
In both years there were 132 injuries from those collisions.
In 2010, police policy on chases was toughened to include criteria such as stopping a pursuit when the location of the offender's vehicle became unknown, if the distance between the police and offender became too great or if the officer knew the driver's identity.
Geoffrey Alpert, a professor in University of South Carolina's criminology department, has been studying police pursuits for 25 years and has recently completed a national study on pursuit driving, funded by America's National Institute of Justice.
He said many cities in the United States have a stricter pursuit policy than New Zealand.
"We're resolving it by having the departments restrict their pursuits to violent crimes and that has worked very well in our major cities. Our pursuits have been reduced by 67 percent."
Professor Alpert questions who police trying to catch during the chases.
"Are you catching speeders or are you catching murderers, armed robbers and rapists? For the most part I think you're catching speeders and kids making stupid decisions."
A higher percentage of pursuits being abandoned was good sign, but New Zealand police should consider further restrictions, chasing only violent criminals, he said.
Police road policing national manager Superintendent Carey Griffiths said they did not know why there was a trend of increasing crashes, injuries and deaths from pursuits despite officers abandoning more.
There were a number of possibilities which would cause the trend and it was hard to speculate on the causes without more information, Mr Griffiths said.
About a quarter of vehicles pursued by police are stolen, with about half of those drivers driving illegally, he said.