Risk of travelling by each mode relative to bus for children aged 5-16 years. Bus = 1. (data from Hensher)

Following an investigation into the death of a cyclist, a New Zealand Coroner has publicly called for hi vis clothing to be compulsory for all cyclists. Wellington Regional Coroner Ian Smith reckons it’s a “no brainer”.

Coroners undertake expert investigations into the circumstances surrounding deaths. They provide an invaluable service to the community in ensuring information about risks to life is drawn to the attention of government and the wider public.

Yet they sometimes – and seemingly increasingly – tend to make sweeping public policy recommendations based on the circumstances of one particular case. Moreover they tend to give insufficient weight to, or ignore entirely, basic concerns of policy-makers like costs vs benefits, practicality, equity implications, and community acceptability.

On Friday, New Zealand blogger Eric Crampton searched Google NZ with the words “Coroner recommends”. That exercise yielded a list of 22 cases where Coroners had made recommendations on matters of general public policy ranging from improved privacy controls to age restrictions on access to butane and other inhalants.

I’ve picked out the recommendations that seem to relate to development:

Coroner recommends that all farm houses be fenced off

Coroner recommends people wear hard hats when climbing ladders to prune trees

Coroner recommends that you should have to have a licence to rent a nail gun.

Coroner recommends clearing trees near train crossings.

Coroner recommends national manhole safety guidelines.

Coroner recommends helmets for riders of motorised skateboards.

Coroner recommends changes to design of future prisons

I don’t doubt there’s a good chance many of the deaths investigated would’ve been avoided if these Coronial recommendations had been implemented at the time.

But it’s not so obvious they’d all be good policy. Mr Crampton’s view is a fair number of the 22 sets of recommendations would “fail any reasonable cost-benefit test”. He says:

Mandatory high vis clothing for cyclists, licenses for nail guns, and mandatory skateboard helmets all seem exceptionally unlikely to pass any kind of ‘is this a reasonable policy’ test.

Of course many recommendations made by Coroners are appropriate. But in too many cases there’s little sense they think about the public policy implications of what they’re recommending.

This tendency to make policy in a vacuum – to extrapolate to the wider world from one highly specific case – isn’t confined to New Zealand. It happens here too and of course the media love it.

Last week The Age ran an editorial, Why don’t our children have seat belts in buses?, arguing that Victoria’s Minister for Transport, Terry Mulder, should make seat belts in school buses mandatory.

The leader writer drew authority from a March 2011 recommendation by the State Coroner, Heather Spooner. She investigated the deaths of three people in a bus accident in 2009 and “called for several changes to this state’s policies on seatbelts in buses” (I haven’t been able to read the reports because the links to them on the Coroner’s site haven’t worked for over a week).

Mandatory seatbelts in school buses would seem to be another “no-brainer”, surely?

Perhaps, but there’s more to it. We need to think about how effective they’d be and what they’d cost.

A study in the 1990s by Austroads found 24 children aged 5-17 years were killed while travelling to and from school by bus during three years studied. However only 2 of those children were killed while passengers in the bus.

The most dangerous part of bus travel for children is getting to and from the door to the bus, especially in the afternoon. That’s when they’re most likely to be hit by another vehicle, or by the bus.

Yet the main travel risk for children isn’t buses at all. A study by Professor David Hensher found it’s more dangerous for children to be driven, or walk or cycle, than travel by bus or train (see exhibit).

When exposure is accounted for (i.e. kms of travel), taking the bus is 1.4 times safer in terms of the risk of death or serious injury than being driven; 4.4 times safer than walking; and 55 times safer than cycling. Travelling by train is safest of all.

Just to drive the message home, here’re some statistics from the US:

Every year school buses carry some 24 million students and collectively travel more than 4 billion miles…..School buses have a rate of 0.2 deaths per 100 million miles traveled. The rate of deaths in automobiles is eight times higher……Over a span of 11 years, from 1994-2004, a total of 71 passengers on school buses died in crashes. In the year 2004 alone, traffic accidents killed 31,693 people travelling in cars and light trucks.

Fitting buses with seat belts is costly. In Western Australia, where seat belts are being phased-in over a ten year period, it costs $26,000 to install seat belts on a bus. However if structural changes are required in older buses, such as strengthening mounting points, it can cost up to $71,000.

The Age cites a ten year old estimate that it would cost between $440 million and $4 billion to retro-fit all buses in the country with seatbelts.

In states like Victoria without dedicated school buses, it would be necessary to retro-fit a large proportion of the State’s entire bus fleet because they’re used for multiple purposes.

Seatbelts could also present operational issues. On scheduled services, drivers could be obliged to check that all children who board have put on their seatbelt. That could slow down services and increase costs.

Mandatory seatbelts on buses might seem like a “no brainer”, but spending the money in other areas – like redesigning bus stops to make them safer, or building dedicated cycling infrastructure – would have a far greater impact in terms of lower child casualties.

Since money is always scarce, that would seem to be the real “no brainer”.

In fact if we follow “Coroner Logic”, it would be much safer for children if parents were compelled to drive them rather than permit them to walk or cycle.

The substitution of driving for active modes is probably a key reason for the enormous drop in the number of child pedestrians killed nationally each year between 1990 and 2000 (from 27 to 9) or seriously injured (from 360 to 213).

But that would ignore a host of issues associated with non-active transport. They include traffic congestion, emissions, pollution, obesity, and the possible long-term health implications for the children.

It would be possible in theory to design a bus that was fatality-free (or a plane for that matter) but the cost in terms of money and negative externalities would be ludicrous. There are diminishing returns in improving in-bus safety – far better to spend available funds on other improvements.

So far as the Wellington Coroner’s recommendation that cyclists be compelled to wear hi-vis clothing is concerned, it’s obviously very similar to the mandatory helmet law. There’s lots that needs to be thought about there – two key questions are: what’s the measured benefit of hi-vis?; what’s the deterrent effect?

Coroners should be less grandiose when thinking about what they can sensibly recommend (a change in legislation might be necessary). They need to be more concious of their limitations and put more effort into understanding the wider policy implications of their findings.