More on WOF checks

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

Clive Matthew-Wilson 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 WOF 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.

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