Blood Alcohol
I blame the feral response to National’s announcement – that they will not be dropping the legal blood alcohol limit to 0.05 g% – squarely on the media. I am certain that it is the media’s propensity always to give the maximum amount of airtime and newsprint to the most hysterical over-reaction that encourages people to use rabid hyperbole instead of rational argument. Blood on their hands? Are they for real? Scandalous! Thunders National Addiction Centre director, Doug Sellman who adds this gem:
““They are throwing that all away and saying, `We are quite relaxed about 30 deaths and 680 injuries and $230m’.”
No, Prof. Sellman, National are saying “We suspect there is a great deal of bullshit in your figures”. I have to agree with them.
Estimates of the reduction in harm achieved by lowering the legal Blood Alcohol Concentration (BAC) from 0.08 to 0.05 are usually derived from studies like the ones in the WHO graph:
Assessing the relative risk of an accident will give you a rough idea of how many fewer accidents will occur. And from that you can work out lives saved. Possibly. This work has mostly been done using simulators in very controlled circumstances. The nice smooth looking curve is not so much a measure of the real-world risk, but a measure of the decreased speed of reaction and decision-making. It is therefore unsurprising that this produces such a neat graph – after all, we know that alcohol depresses reaction times in proportion to the BAC. It does not tell us whether accidents and fatalities would be reduced so attaching crash figures to this information is merely an exercise in math rather than a real-world scenario.
A BAC of 0.05% may put a large number of responsible citizens afoul of the law and achieve little or nothing in terms of road safety.
”Zador’s well-known study (Zador PL, Krawchuk SA, Voas RB. Alcohol-Related Relative Risk of Driver Fatalities and Driver Involvement in Fatal Crashes in Relation to Driver Age and Gender: An Update Using 1996 Data. J Stud Alcohol2000;61:387-95.) provides us with some actual crash data from the US databases. Zador showed that people with a BAC between 0.02 and 0.049 had a 2.5 times higher likelihood of a fatal crash and those with a BAC of 0.05 to 0.079 had a 6 times higher likelihood of a fatal crash. Unfortunately, as I have pointed out before, these are very wide bands, making it seriously difficult to determine the best place to set a maximum BAC. It is highly likely that the arbitrary nature of the bands has predetermined the arbitrary nature of a 0.05% limit. Again, it does not really address the issue of a safe BAC, but at least it indicates that more alcohol produces more fatal crashes.
A recent meta-analysis has suggested that no BAC may be considered “safe” for a complex activity such as driving. Having read the paper, I have no problem with this conclusion at all. The upshot is that, despite the emotive language and the dubious figures cited in the media, the debate around a reduced BAC limit is entirely missing the point. The question should be whether we should people to drink any alcohol and then drive.
This question is not as simple as it seems. Danyl at the Dim-post baldly puts it thus:
“The problem is that the 30 to 60 people that will die during the two year research period don’t know who they are so they don’t know that their freedom has been compromised, while the many thousands of people who like to have a few drinks and then drive home do know they’ll be trivially inconvenienced by a reduction in the drink-drive limits.”
Sarcasm aside, this argument overlooks the fact that we already allow dangerous people on our roads. The elderly and the young both have high accident rates even when sober. A teenager with a BAC of 0.5 has an increased risk of a fatal crash up to 17 times the rate of a sober driver. An adult with a BAC of 0.8% is not statistically more dangerous than a perfectly sober 17-year-old. Should we deny the young and the old the ability to drive themselves?
There are people who routinely speed and people who routinely tail-gate. There are those who have sleeping problems and drive tired and those who drive under the influence of pain killers and cough medicines. There are those who drive while adjusting their radios and those drive with children in the car. Some drive cars that are falling apart and some drive left-hand drive imports. For one or two of these drivers we have laws that may cause one to be fined, but the vast majority of these motorists drive with impunity, despite being far more dangerous than the average driver.
We choose to allow these people on the road because we strike a balance between increasing our danger and a person’s freedom to drive. Sometimes the risk is too great (people with no license, the recidivist drunk, the drunken youth) but usually we accept an increased risk of around 2-3 times greater than normal (most of the people mentioned above). The question therefore remains as to exactly what reduction in risk we will be achieving by lowering the BAC level to 0.05%. The data is not yet conclusive. Most countries who have lowered their BAC from 0.08 to 0.05 have experienced about a 8-12% improvement in accident statistics. As the lowering of the limit has invariably been accompanied with a raft of other measures and a police blitz on alcohol, it is hard to be sure exactly what this means. Joyce is right to want to gather better data so that we know whether such a reduction is actually worthwhile.
The decision is not as trivial as Danyl makes out. A BAC of 0.05% may put a large number of responsible citizens afoul of the law and achieve little or nothing in terms of road safety.
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Jul 27 10 8:58 pm
Nothing is risk free MacD – nothing at all.
And you can fiddle around with BACs or speed limits to your hearts content and people will still be killed on our roads and sometimes by those who are grossly intoxicated who don’t give a fig for the rules anyway.
Its an asymptote with BACs though the biggest change would be to take it to zero and that would make diddly difference to the road toll.
In truth making better roads with better layouts would be a more productive exercise but road engineering doesn’t have the same posturing value as social engineering. And it costs more
And of course NZ has a Calvinist heritage with loathes people having any pleasures in life.
Andrei´s last [type] ..Its scandalous I tell you- scandalous
Jul 27 10 9:57 pm
the biggest change would be to take it to zero and that would make diddly difference to the road toll
Possibly. Possibly not. It’s nice that joyce seems like he wants to find out which is true.
In truth making better roads with better layouts would be a more productive exercise
Indeed. Although it would undoubtably be far more expensive per life saved, assuming lowering the limit saves any lives at all.
Jul 27 10 11:50 pm
You know MacD the road toll in 2009 is significantly lower than it was in 1969 with more than double the cars on the road in 2009 than 1969.
And the reason has little to do with politicians making tougher laws etc and everything to do with engineers designing safer cars and better roads.
You can, in the laboratory, do your experiments showing a statistical degradation of reaction times after one or two glasses of wine yadda yadda with subjects who understand the purpose of the experiment but does this translate to anything significant in the real world?
We will never know because its untestable but what is for sure the guy who has just had a flaming row with his wife is probably a bigger threat to other road users than the guy who has just had two glasses of wine with his meal.
Andrei´s last [type] ..Its scandalous I tell you- scandalous
Jul 28 10 1:02 am
You and I probably agree on this. Countries that dropped their BAC to 0.05% experienced a brief sharp drop in accidents – probably secondary to people not drinking at all, simply because they were unsure of the “safe” amount to stay legal. Within two years the drop assumes the decline that ALL developed countries experience as they develop safer roads and safer cars. Including the countries that have BACs of 0.08%.
Jul 28 10 2:59 pm
Hey the point is that lowering the blood alcohol level will discourage idiots thinking they can handle alcohol and drive home. There is no place on our roads for drivers having it both ways. Not when my loved ones are using the road, especially. Nothing is more pathetic and heartbreaking than standing at the side of a road looking at innocent & killed victim(s) of a drunk driver.
National can also (proudly) take credit for lowering the drinking age. Was that a brilliant success?
Once again, this ratbag Key/English led National Party govt stands guilty of attempting to put immagined popularity before country, principle and what is right.
Jul 28 10 8:53 pm
lowering the blood alcohol level will discourage idiots thinking they can handle alcohol and drive home.
I think that is wishful thinking. See my comments to Anna below.
While I agree with your sentiment, the simple fact of the matter is that drunk driver accidents are almost always caused by people WELL over the limit. Moving the limit from 0.08% to 0.05% is likely to make little or no difference to accident/fatality rate, no matter what the MoT say.
National can also (proudly) take credit for lowering the drinking age.
Really? I was under the impression that Labour was in power when this bill became law. Regardless, the majority of MPs in Labour voted for the bill.
Jul 28 10 11:13 pm
Was it not Jenny Shipley? As P.M.? Shameful, who ever it was. Pretty sure it was J.S. and her govt.
Quite simply, anything discouraging any driver driving after any drinking is responsible governance. No one minds imposing regulation on firearm owners. Driving is a responsibilty. Not a right. Cars are weapons.
Jul 28 10 5:29 pm
I don’t disagree with what you are saying but for me, the issue about lowering the BAC from 80 to 50 is not just about scientific information. I have dealt with hundreds of BAC and BrAC and urine AC calculations and case work over the last ten years and it is very much about what people think they can get away with drinking, i.e. the actual drinking culture.
New Zealand is a hard drinking country and has so far resisted attempts to alter the national perception that drink driving is OK. Although the UK still has a BAC limit of 80, there is a stigma attached to drink driving that is not present in NZ. Also, let’s remember that the blood:breath ratio in England and Wales is different, which means that rather than a BrAC of 400, the law stipulates 350, which does make a tangible difference in what we see in court cases.
Jul 28 10 6:26 pm
the issue about lowering the BAC from 80 to 50 is not just about scientific information
Post modernist? The don’t let facts get in the way of the agenda you want to impose on everyone else.
New Zealand is a hard drinking country and has so far resisted attempts to alter the national perception that drink driving is OK.
We a harranged endlessly with propaganda about drink driving to the point where it is counter productive.
And no most people don’t think its OK to drink drive but most people are also sick to the back teeth of being hectored by post protestant puritans about drinking and smoking and eating fatty foods.
Andrei´s last [type] ..Its scandalous I tell you- scandalous
Jul 28 10 7:47 pm
Anna:
I agree with you about the drinking culture of New Zealanders. However, I doubt very much that lowering the limit will make any difference to it. I think you will find that the vast majority of people with a positive breath alcohol will have one below 250mcg (the equivalent of 0.05%BAC). Few will risk driving with a BAC higher than this because it is truly impossible to tell whether you are under or over the 0.08%.
I think you will find two types of people in the 0.05-0.08% range. Those that did not eat while drinking or drank too fast, pushing their BAC temporarily high, and those who don’t give a rip about the limit but have not (yet) consumed enough to get over it. The first group will be criminalised for a stupid oversight. The second will be caught at some other checkpoint.
It will be interesting to see if my hypotheses pan out in the research that Joyce has commissioned.
Jul 29 10 10:30 pm
I realise that my experience is biased towards those people over or close to the drink drive limit but many thousands of people drive in excess of the breath alcohol level all the time. In my experience (casework and anecdotal), after a couple of drinks most people misjudge how affected they are by alcohol. I have given many presentations about alcohol and its effects in terms of forensic alcohol calculations and the majority of audience members admit to not being sure how much they should consume prior to driving but it doesn’t stop them drinking more than they should, largely beacuse they know their judgement was impaired at the time they made their decision even if they didn’t recognise that until after the event (usually the next day).
My personal preference would be to reduce the BAC so that it is into the Subclinical zone (as opposed to the Euphoria stage – see http://www.fsrl.co.nz/2010/04/13/categories-of-drunk/) for reasons as set out in that post and the associated one.
I also would like to see the blood:breath ratio adjusted to be in line with what the scientific literature suggests, being 2300:1 (= 350 in breath) rather than 2100:1 (which is NZ 400 in breath).
I agree in general with your breakdown of how people drink – what I have found is that by explaining to people about the effects of food, their height, weight and gender and the type of alcohol they are consuming they understand how to manage their drinking a bit better. Obviously this approach will work in a positive way for some people whilst others will abuse it – that’s human beings for you.
Anna Sandiford´s last [type] ..To reduce or not reduce – that is the blood alcohol question
Jul 28 10 9:57 pm
Call me a wowser if you will, but personally I believe that drinking, drugging and driving have no place on any road at any time, there is no rationalization that could ever make this right, it needs to be zero BAC and that’s it. The tricky part of this is that those of us who take prescription pain killers are wide open at the moment as it’s up to the officer to determine whether or not your medications are affecting your driving, and lord knows some affect walking let alone driving.
Bring on the automatic vehicles with gps..” jome hames, hic, and sake it mnappy”
http://www.medrate.co.nz
Medrate Admin´s last [type] ..Welcome
Jul 29 10 10:34 pm
The new drug driving law does allows for people who are taking medications to not be charged with drug driving – it’s a question of how the blood sample result is interpreted plus the correct interpretation of the law.
If a police officer decides that someone has not satisfactorily completed a roadside impairment test, bear in mind that these tests have only been mandatory since last December and that the interpretation is subjective – depends on the experience of the officer in question; there is no “pass” or “fail”. If someone is charged with drug driving, it is always worth looking at the whole of the case circumstances and science before deciding whether there is a case to answer.
Anna Sandiford´s last [type] ..To reduce or not reduce – that is the blood alcohol question
Jul 30 10 8:56 pm
We have had nearly a decade of research here in the 70s when Prof Don Bevan and Morgan Fahey studied virtually every accident in the Christchurch region. Their conclusion was that the 80 level at which those who would have a “bad day” would take out their furies with their cars might justify such a level, but the overwhelming majority of us don’t have such a reaction and most of those who do will bring themselves to the attention of the Police because they will already be aggressive and rude and reckless drivers.
The first level a drinker can recognise comes at about 108, when the teeth start to feel different, and the jaw muscles to constrict( the American expression “getting tight”). This is the warning that the drinker is about to hit 120, at which it is possible to quantify a reduction in the ability to perform an unfamiliar task (like avoiding an unexpected manouvre in traffic). The idea they had was that this connection between the “tight” sensation and the onset of impairment would be publicised and the road toll could be controlled without damaging the hospitality industry. Didn’t happen. All the effort has been put into other things, none of which work. Shame .