More on WOF checks

December 13th, 2012 at 3:00 pm by David Farrar

writes at Stuff:

The proposed changes to the vehicle licensing laws are a case in point. According to the Government, most of the changes involve stretching out the period between warrants of fitness (WOFs) from six to 12 months.

Sounds good. The government geeks assured us there would be no safety compromises as a result. Beware of geeks bearing gifts.

No, they never said there would be no compromise. They said the benefits probably do not exceed the costs.

Despite a glowing endorsement of the Government’s plans by the AA (which is the beneficiary of several lucrative government contracts), the best independent research suggests the average motorist will save very little and might lose a lot.

A ridiculous attack on the AA. The AA has battled Governments on many many issues they disagree with.  To suggest they are not impartial is a classic attacking the man, not the ball. Add to that the mischaracterisation of what the Government has said, and he is off to a bad start.

A recent independent report by Australia’s Monash University, contradicts many of the claims by the Government and the AA.

The report concluded that extending the period from six to 12 months is likely to increase the road death toll by between 1.3 deaths and 25.6 deaths per year. Monash also predicts injury accidents might increase by between 16 and 325 per year.

Not the selective cherry-picking. He overlooks the actual conclusion from Monash. The report is here.

In terms of the cost-effectiveness of the New Zealand WoF scheme as a whole, we placed the known costs of the scheme to the motorist as one side of the cost-benefit equation and then estimated the necessary benefits to equal these costs, represented by Figure 10. The benefits started to exceed the costs only when the drop in crash rate associated with the scheme reached 12%. This is evidently quite a demandingly high level of injury reduction. It is unlikely from the literature and from the rate of fault detection in the NZ WoF scheme that 12% of crashes can even be considered to be caused by mechanical defects, let alone able to be prevented by periodic inspection and repairs.

So Monash said that six monthly WOF checks are only cost effective if they reduce the crash rate by 12%.

Now recall that mechanical defects are implicated in only 2.5% of vehicle crashes and are the sole cause in only 0.4% and you see that there is no way the six monthly checks reduce the road toll by 12%.

So Monash concluded:

Despite these safety benefits estimated, the costs to the motorist of the 6-monthly inspections over and above the annual inspections were estimated to be considerable. This means that the 6-monthly inspections compared to annual inspections were not considered to be cost-effective.

But Matthew-Wilson said:

The Monash report found: “[changing the period for WOFs from six months to 12 months is] not considered to be cost effective”. In other words, there will be little or no saving from the changes.

That is the exact opposite of what they found. Go read the report for yourself.

10 Responses to “More on WOF checks”

  1. bhudson (4,770 comments) says:

    He’ll have a face like a lemon having had that pointed out. Looks like his argument is a bit of a dog.

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  2. lastmanstanding (1,746 comments) says:

    Only need annual WOFs. The self interested VINZ etal are opposed because they see their revenue dropping. What we really need is complusory 3rd party insurance like other countries.
    Those who insure also pay for the bludgers who dont/wont pay. Way to fix it is confiscate and crush any car without current registration or WOF or 3rd party insurance.
    Would get the wrecks off the road and free up the space for those who pay their fair share.

    And jail offenders for 3 months. That will soon sort the problem out.

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  3. Manolo (22,374 comments) says:

    Less talk and more action. The Minister should act decisively and take AA’s advice.

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  4. Murth (27 comments) says:

    What is the procedure to complain when the media misrepresent academic research to this extent? I’ve encountered it before where the media have reported the exact opposite of the conclusions the researcher reached because they seem to fail to understand it.

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  5. Chris2 (924 comments) says:

    Thanks David for putting up such a prompt posting.

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  6. SouthernRight (54 comments) says:

    Clive Matthew-Wilson is a dog and lemon, why is that you ask? He is always sniffing the wrong butts and talking a load of bitter crap.

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  7. Auberon (811 comments) says:

    Too right SouthernRight – the man’s a meat axe. This is his second credibility strike in a year, the previous being the carnage he predicted when the right hand rule changed because millions weren’t spent on months of educational publicity. He predicted people would die. Truth is it was easy and, as usual, Clive was wrong.

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  8. Steve (North Shore) (5,004 comments) says:

    The WOF should be done on mileage, not time. There are some good 40 year old cars out there that will never die, and there are MANY two year old buckets of bolts that have very high kilometers.

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  9. Rex Widerstrom (5,130 comments) says:

    @Steve (North Shore):

    What an excellent suggestion. I wonder if there’s any data on the kilometres travelled between inspections, and how many cars which have done almost no travelling are receiving checks with the same regularity as, say, that driven by a travelling salesperson like the one I know whose territory is the entire South Island, plus Wellington, the Wairarapa and Hawkes Bay?

    My father drives to the local shops once a week and over the Wanui hill to the hospital once a quarter but gets soaked for a new WoF (and often unnecessary work by certain local mechanics who know elderly folk won’t want to take their cars over the hill and then face getting public transport home and back to collect it).


    Don’t blame the meat axe, blame the media outlet too lazy (or more likely to grossly under-resourced) to carry out even a perfunctory analysis as DPF has done (ot criticising DPF’s work, but I don’t imagine this post even took him 30 minutes to write).

    Once we could expect rigorous analysis and factual reporting from our media. Then it withered to “he said / he said” which was seen as providing “balance”. Now it’s just “he said” from some tame one-trick ponies whose opinions on a topic are so predictable as to make those of some blog commenters look positively sensational.

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  10. Richard (85 comments) says:

    While good at publishing on car reliability, Clive M-W ain’t so good at commenting on matters beyond that let’s remember the nonsense he spouted on the give way rule –

    I get the feeling that many of his press releases are more about promoting himself than the actual issues.

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