Police are threatening to permanently reduce the speed limit tolerance in an effort to reduce the road toll.
Since 2010 police have been cutting the 10kmph tolerance allowed in 100kmph speed limit areas to 4kmph over public holidays.
The 4kmph tolerance has now been introduced for the rest of February.
National manager road policing Acting Superintendent Rob Morgan told The Dominion Post yesterday that it may be here to stay.
"In the long term we will be discussing whether we bring it in permanently or not," he said.
He said police have found the lower tolerance is having a positive effect on the road toll and "on that basis... would be considering it very seriously".
"It will really be an evidence-based decision, it's about an assessment of whether it saves lives."
Mr Morgan said for every 1 kmph reduction there were 4 percent fewer deaths internationally.
"At the end of February, we will consider the outcomes and, if the analysis supports it, we will consider further long periods or even permanently lowering the tolerance."
A police spokeswoman says since the 4kmph limit started in 2010 holiday period crashes have fallen 46 percent.
Ministry of Transport figures for 2009 show speeding was a contributing factor in 100 fatal crashes, 361 serious injury crashes and 1274 minor injury crashes.
Transport Minister Gerry Brownlee says any change in the speed tolerance policy is an operational decision for the Police Commissioner. But if a long-term change is considered he expects to be consulted.
But motoring lobbyists say a reduction in speed may not achieve significant results - they doubt it would make a difference in the road toll, and worry it would target innocent motorists.
“The focus should be on drivers who are going excessively fast, or extremely slowly," Automobile Association motoring affairs general manager Mike Noon said.
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