Safe Speed Forums

Remember, the main issue is not whether drinking impairs, or how much or how soon, but whether the level of impairment differs sufficiently (or at all) between 50mg and 80mg to justify changing a law that is already not enforced adequately.

There is a theory which I neither support nor refute - as there seems to be no research upon which to base such a decision - it goes like this :-

Just about every driver can "improve" his or her driving for a short period of time (ie signal properly, obey the limit, correct lane discipline, sensible distance from car in front, not cutting in etc etc.) , especially when followed by a police car or taking a driving test.

drivers who have had a drink and who are aware they may be close to the limit almost unversally adopt this strategy to avoid giving the police a reason to stop them.

Numbers of them are stopped, in spite of this extra care, either because of a collision or because something in their driving aroused suspicion that they may be under the influence.

The extra care does allow some of them to avoid attracting the attention of the police, which leads to their under representation in the accident figures. Giving rise to a false impression that low levels of booze make you safer.

Those who support the theory are of the opinion that as so many are caught in spite of the extra care, the conclusion must be that any level of alcohol decreases ability to drive.

As I said before I neither support nor refute this. Its a theory that seems to be very popular amongst staff in casualty departments.

You're still missing the point - you can quote interesting but irrelevant scientific papers until the cows come home - it won't make them any more relavant and it certainly will not convince anyone.

That is what is done by people who believe that are, or are likely to be, over the limit,

The Borkenstein figures look at actual accident involvement, not detection, and therefore any variation in the detection of non accident involved drivers is irrelevant

It is worth adding that in my view the lower accident involvement of drivers with low but above-zero levels of alcohol does not result from any actual enhancement of driving ability, but largely from tending to drive at less busy times of day.

I am sorry you lack the knowledge to understand how mistaken you are in your assertions, but I don't have the time to waste in further discussion of this point.
I just hope no one risks their licence, and possibly their life, by driving after the rapid ingestion of 4 units of alcohol.

So near misses are not relevant?
The problem with only looking at accidents is that you don't find out how many were avoided by the prompt actions of other drivers and so you don't get a true picture of the potential danger, or lack of danger.

My experience is that those who are a lot over the limit are too far gone to able to think clearly about anything and definitely don't modify their driving. However I do believe that drivers who are near the limit do frequently try to "improve" thier driving. I have been paying particualr attention to drink driving cases since this thread started and have been surprised just how many times the police statement has words to effect of " I stopped him because his driving was too precise to be normal"

So near misses are not relevant?
The problem with only looking at accidents is that you don't find out how many were avoided by the prompt actions of other drivers and so you don't get a true picture of the potential danger, or lack of danger.

I doubt any 11 stone men will be risking their licence by consuming exactly 4 units of alcohol, however I understand why you may believe that they are, based on your experience of what defendants have told you as a JP.

4 units drunk however quickly are extremely unlikely to put a man over the 80 mg limit.

On a different note, I do have grave concern for anyone working in an official capacity with such personal unsubstantiated opinions.

"As a rough guide"
"after about an hour"
"This is an idealised picture as rates of absorbtion vary so much"

Can they be separated from practice, or do they cloud judgement?

Sorry, but system-wide this holds no water.

Can they be separated from practice, or do they cloud judgement?

It wasn't meant to. It was a specific response to a specific point.

I quoted the paper from Addiction which concentrated on the degree to which reaction times are slowed by alcohol.
PeterE quoted a paper by Borkenstein which drew its data from accident reports.

My point is that the Addiction paper can sensibly be extrapolated to show that low levels of alcohol pose a risk to drivers - because a delayed response is clearly not a good thing. Athough it makes no attempt to quantify that danger and is not, in my opinion, enough on its own to justify a lower legal limit.
Borkenstein throws some welcome light on accidents but doesn't contain anything which can sensibly be extrapolated to other aspects of motoring.

I went to the trouble of quoting some medical research papers to make it clear that my comments were not personal opinion but accepted fact in expert circles.

"As a rough guide"
"after about an hour"
"This is an idealised picture as rates of absorbtion vary so much"

The research papers you suggest 'make it clear' that 4 units of alcohol would put an 11 stone man over the limit do nothing of the sort. They are irrelevant.

Extrapolation is not a particularly reliable statistical method however, since the Addiction study bears very little similarity to the driving task, which is so much more than 'lizard-brain' quick responses to emergent situations.

The Borkenstein results give the much more appealing option to interpolate, given their direct bearing on accidents!

It does give valuable information about accidents but doesn't cover near misses. So often a near miss occurs when an aware driver prevents an accident by an evasive action. Surely it would better if that evasive action wasn't necessary which is why more work on near miss situations is so important.

Once again it is necessary to analyse whether there is a greater incidence of "near misses" attributable to low BAC drivers v those for the general motoring population - and as there is no collection of stats on near misses this is going to present something of a problem, so any changes to the law derived therefrom will be based upon guesswork again.