New 110kmh limits may increase the road toll
Tuesday, 10 October 2017
You'll soon be able to drive 10kmh faster on some New Zealand highways as the speed limit is bumped up to 110kmh.
The first changes will take place on the Tauranga Eastern Link and parts of the Waikato Expressway by the end of the year. Other 'Roads of National Significance' the Government is considering for speed limit increases are the Kapiti Expressway and the southern section of the Christchurch Motorway.
A run of horrific car crashes across New Zealand since Sunday prompted police to label our roads 'battle zones'.
There have been arguments for and against increasing the speed limit. But given police predict 60 more people will die on our roads this year, what's the likelihood faster speed limits would mean more accidents - and more deaths?
**READ MORE:
* Government gives thumbs up to 110kmh limit
* Nearly 300 road deaths this year - and counting
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* Man dead in hospital car crash**
Road safety researcher Doctor Glen Koorey said research showed for roughly every 1 per cent of speed increase on highway or open road speeds, there was a 4 per cent rise in fatal crashes. A two per cent increase in injuries would also occur.
'For every 10km you change the posted speed limit, it seems to nudge the observed [average] speeds about 2kmh to 3kmh an hour… you're talking a 10 per cent increase in fatals, for example.'
The opposite was true, too - a speed reduction of 1 per cent resulted in a 4 per cent fall in fatalities, he said.
Koorey thought speed limit increases were a 'political sop'.
'It's an easy win, an easy vote winner. At a time when the road toll is going up it just feels like not the right answer.'
However, he was pleased the Government was focusing on only a few roads for increases.
A 2012 University of Otago public health project report investigated the impact of a speed limit increase. It assumed a blanket change of 110kmh to all 100kmh roads in New Zealand. The authors noted the study had some limitations.
Its figures didn't represent what would happen with a roll-out of an increased speed limit in very select areas as will occur. Those numbers would likely be even lower.
But it showed that faster cars would mean more deaths.
The report said a 10kmh speed limit increase would result in a 4kmh increase in mean speed from the current 96.36kmh to 100.36kmh
Using a model for the relationship between speed and road safety showed a 4kmh increase 'would result in an additional 35.4 fatal, 110.6 serious, and 171 minor injury crashes per annum if the speed limit increase was applied to all 100kmh state highways.'
If the increase was only applied to 100kmh motorways, an additional 1.2 fatal, 3.5 serious and 16.5 minor injury crashes per annum were expected.
Speed was a bigger issue than the number of crashes occurring and it needed consideration, Koorey said.
It would cause crashes with a greater chance of fatal and serious injuries.
Koorey pointed to the open speed limit reduction in the 1970s from 100kmh to 80kmh. That was introduced to help cope with a fuel shortage. The speed limit was put back up in the 1980s.
'It was quite clear that there was a drop in fatals and crashes in the first instance [reduction] and a jump in them the second time around [increase] as well,' he said.
'It just shows you that even if you do nothing else and all you do is change the speed limit, there was a change in behaviour and a change in the outcomes… there's a lot of roads where we would have to ask if they are the right speeds at the moment.'
The University of Otago report said in its 2012 report New Zealand roads were not built for speeds over 100kmh.
The roads that would be affected by the increases to 110kmh by the end of the year are newer motorways built differently.
Associate Transport Minister Tim Macindoe announced the increases in August.
'The faster 110kmh speed limit will only apply to stretches of roads built to a standard where the higher speed limit is both safe and appropriate,' he said.
'This includes having at least two lanes in each direction, a median barrier, no significant curves and no direct access to neighbouring properties.'
A police spokesperson said: 'Police [support] the principle of introducing a 110 kmh speed limit on appropriate roads where safety will not be comprised.'