There has been much comment in the media and on Sciblogs about the effects (or not) of a lowering in drink driving “accidents” (although the Road traffic Police in England refer to them as ‘avoidable incidents’, because they are; there’s nothing accidental about them) as the result of a reduction in the NZ blood alcohol concentration from the current level of 80mg alcohol/100ml blood to 50.
Personally, I think that although a zero drink drive limit would not immediately and dramatically reduce the number of road traffic incidents in which alcohol is a factor, time would make its mark. Drink driving is socially acceptable in New Zealand, more so than in other countries. Kiwis drink hard and long. Peer pressure in my age group (currently late 30s) that reduced drink driving in England and Wales during the 1980s and 1990s does not exist to the same degree here.
People drink and drive here because there is the general perception that the driver can “calculate” what they can get away with drinking before they are over the limit. By the time they are over the limit, they are in the Euphoria stage and, in my experience, mostly in the Excitement stage. For reference, the following table demonstrates the descriptive stages of drunkenness and the associated blood alcohol concentration:
|Blood alcohol concentration (mg/100 ml)||Stage of Influence||General signs/symptoms|
|10 — 50||Subclinical||No obvious effect. Observed behaviour appears nearly normal.|
|30 — 120||Euphoria||Mild euphoria, sociability, talkativeness. Increase in confidence; decrease in inhibitions. Reduced attention and judgement. Some sensory-motor impairment. Reduced rate of information processing.|
|90 – 250||Excitement||Impaired balance, reduction in coâ€‘ordination leading to staggering or erratic gait, possible nausea, poor sensory perception, drowsiness. Increase in reaction times.|
|180 – 300||Confusion||Dizziness, ’drunkenness’, confusion, disorientation. Apathy, increased drowsiness, lethargy. Increase in pain threshold; vision disturbances.|
|250 – 400||Stupor||Approaching loss of motor functions, inability to stand or walk as result of muscular in-coordination, “passing out”, incontinence.|
|350 – 500||Coma||Unconsciousness, depressed or unresponsive reflexes. Circulatory and respiratory depression. Reduced temperature. Approaching the health danger limit, possible death.|
|450+||Death||Probable fatal limit due to respiratory paralysis|
(adapted from Garriott J. ed. c2003. Medical-legal aspects of alcohol. Tuscon, USA: Lawyers & Judges Publishing Company, Inc. and Walls H., Brownlie A. 1985. Drink, Drugs and Driving. Sweet & Maxwell: London)
I don’t believe that anyone should be making a decision as to whether they can drive if they have gone beyond the Subclinical stage. I realise that lowering the blood alcohol limit to 50 is the top end of Subclinical but the effects of alcohol vary within and between individuals, regardless of the limit stipulated by the law. In that regard, alcohol is a unique drug – no other drug has a level stipulated in law for driving precisely because the effects of drugs are unpredictable and are complicated by mixing of drugs (including alcohol), people’s habituation and other factors.
Until the law changes to a much lower level than 80 or even 50, I will be happy to carry on doing blood, breath and urine alcohol calculations for drink driving cases because it is about what the law says. Plus alcohol is a major contributor to so many other crimes in this country – it’s never going to go away.