Alcohol driving limit question

The only way to be safe is to drive when you know you’ve got 0 units in your system.

And you are not tired, or otherwise impaired in any way.

Also you’re a safe driver.

. If you tested immediately after having a drink it doubled it

Mouth alcohol. Guidelines used to be to wait 20 mins after last drink before breathalysing to avoid a false reading from mouth alcohol.

cynic-al – Member

The only way to be safe is to drive when you know you’ve got 0 units in your system.

And you are not tired, or otherwise impaired in any way.

Also you’re a safe driver[/quote]And not busy texting on your stupid ‘phone…. etc. etc.

hora – Member
Agree- go to any popular pub and its carpark will be full. Not all will be soda-drinking/drink sacrificing friends. In the morning there are always 2 odd cars left there. All have gone

^This. There is an a-hole in our village who is, I think, stretching his luck very thin. He put his BMW X5 on it’s roof on the way back from the pub a month or so back, but the police didn’t find the car until the morning. I’ve seen him diriving early mornings looking like Mr Punch, clearly still the worse for wear, and I’m hoping they pinch him soon.

Report him to the Police.

I think the whole 1 hour per unit is based on similar “science” as the recommended weekly amounts

No it is based on careful clinical studies of IV administered alcohol in known doses. See for example http://www.ncbi.nlm.nih.gov/pubmed/8872236 . Full text here, and a nice paper on volume of distribution. Note the very linear concentration-time curves – unusual for the vast majority of drugs.

The plural of anecdote is not data.

Well, Professor Snark, my experience isn’t in alcohol metabolism specifically but I studied enzyme production with respect to the metabolism of various drugs, with a view to tailoring patient-specific immunosuppressant dose rates in organ transplant recipients. People metabolise things at different rates depending on their genetic makeup, and to try and cater for everyone with a single rule doesn’t always work out. That’s what I’m getting at.

Also, whilst the concentration curves may well be fairly linear, the time taken to eliminate all alcohol from the breath samples ranged from 280 minutes to 455 minutes, so I’m not entirely sure how that study contradicts my point.

On about 3 pints I’m mental on a bike- really smooth and quick.

On zero pints I’m like Bambi on ice on a bike.

In a car I think I’d be lethal on even just two pints.

For the “0 should be the limit” argument it simply can’t be. The body naturally produces alchol and therefore a 0 limit could potentially see everyone banned even if they were teetotal. My job has a blood alcohol limit of 25% of the drink drive limit purely for that reason. Which basically equates to have any alcoholic drink and you are over that lower limit.

Our medical department give the advice of 1 unit per hour for the body to get rid of, this starting from when finish drinking and provided it has not been a lot of drinks.

contradicts my point.

It doesn’t, there is of course between-subject variability in drug metabolism, and dose recommendations are based on mean behaviour with accommodation for variability from subject-to-subject. My point was that 21 units a week recommendations are based on mass epidemiological studies that do not have prospective controls. Whereas elimination of alcohol is an easily studied clinical problem with variation. Hence the one unit per hour is on a stronger scientific footing.

The genotyping drug revolution failed to take off for most treatments because other intrinsic factors, many not understood (drug transporters for example), can have as much effect. Variance in alcohol clearance isn’t subject to these to the same extent because elimination pathways are saturated at the doses we like to administer – It’s the linear elimination that makes alcohol concentrations so predictable. Back extrapolation means that if you are a slow metabolizer, then you might squeak under the limit.