Imagine this scenario – you go to the pub after work and when there decide "just to have the one" knowing you will need to drive home. You then think it might be best to leave the car but reconsider saying to yourself "I feel fine " and get behind the wheel .
Or another, you are at home and have a glass of wine or two after a long week. You have no plans to drive until a text comes in asking you to pick up one of your family from the train station. You hesitate for a moment and then say "Actually I feel fine "and set off on your journey.
What is wrong with this approach?
Ever had a couple of drinks suddenly hit you as you step outside? Imagine this happens when you step outside your car to take a roadside breath test.
In light of the new drink driving limits in Scotland, taking any alcohol and then driving is a gamble. However, there are always situations where people will try to make an assessment of their ability to drive – as unscientific as that might be. Basing your assessment on how you "feel" at the time just before driving does not bear any scrutiny - because that is not how drink driving levels are assessed.
Let's look at the scenarios above and outline how fitness to drive would be worked out. Alcohol has been consumed and your system will be processing the alcohol all of the time you are driving. We all do this at different rates – the alcohol level could be rising or falling.
If stopped by the police, which can occur for a multitude of reasons, a request can be made of you by the police officers if they believe you have been drinking. As long as you hadn't been drinking in the last twenty minutes you would immediately be given a roadside breath test. This simply registers a pass or a fail. If you pass you can drive away a very relieved person. If you fail you would then be taken to the police station where you would be tested on a machine which will provide an actual reading about your alcohol reading at that time. If above 22mcg in 100 ml of breath you will face prosecution.
And here is the twist – the reading that is used to prosecute you is the one that you recorded in the police station. This reading might have been provided some time after you were actually driving but this is the reading that is used to prosecute as the Road Traffic Act uses what can only be described as a " legal fiction " – the reading recorded at the police station is taken as being the reading at the time you were driving.
Your drink driving charge will provide details of the road you were stopped on and the time you were driving. It will also say you drove at that place and time with the drink drive reading that was recorded later at the police station.
So, an understanding of this process shows how dangerous it is to rely upon " how you feel " at the time of deciding to drive as the real test will come in the short time that lies ahead, a timescale that you don't know and during which your alcohol levels may very well be peaking.
Trying to guess your future alcohol levels, especially when we are largely unaware of how our body processes alcohol, is so fraught with danger that the only solid advice is not to get behind the wheel at all.