By Mark Kelly General Manager - Operations
Imagine a friend offered you a drink - a volatile, flammable, colourless liquid described as a powerful psychoactive drug, also used in modern thermometers.
You would probably say “no thanks”.
What if that friend persisted and described the liquid substance as having a molecular formula is C2H5OH, an empirical formula is C2H6O, an alternative notation is CH3–CH2–OH, which indicates that the carbon of a methyl group (CH3–) is attached to the carbon of a methylene group (–CH2–), which is attached to the oxygen of a hydroxyl group (–OH)?1
It doesn’t make you feel much better, does it?
But, if the friend said that he was merely offering you an alcoholic cocktail, you may just relax a little...and drink it!
These colourful descriptions are actually describing everyday alcohol – or more correctly, ethyl alcohol. It is the stuff in beer, wine and spirits.
Now let’s talk about alcohol and how it affects driving. Alcohol is a drug. It changes the way the body functions, in particular, depressing the central nervous system. In other words, it relaxes us.
However, while we love alcohol for its intoxicating and relaxing effects, alcohol has well documented adverse effects on driver performance, especially in terms of cognitive function and psychomotor skill.
Forensic Physician, Dr Edward Ogden explained as follows. ”The amount of alcohol required to affect human behaviour is quite small. Driving is an extremely complicated task. We do it so often we take it for granted. But the driver is required to see, to understand what is seen, to make judgements about speed and distance to be aware and understand hazards as they occur and to see hazards out of the corner of the eye. Alcohol affects all of these things.” Dr Ogden said.
The most recent studies into alcohol and impaired performance were conducted by the National Highway Traffic Safety Administration (NHTSA) in the USA and published in 20002. The study found that even the smallest amount of alcohol decreased a driver’s ability to multi task. The equivalent of one standard drink of alcohol increased drowsiness and decreased vigilance. Two standard drinks decreased perception and visual function and interfered with the driver’s ability to drive within a marked lane. Worse still, this small dose of alcohol actually increased reaction time. In fact all of these functions that are essential to safe driving were affected noticeably at BAC levels below .05%.
Dr Ogden also makes the point that alcohol affects our ability to react to an on-road emergency. “Frequently we hear that someone has driven home affected by alcohol and may have driven home many times affected by alcohol without a problem - and that is because no hazard arose”. said Dr Ogden. “But we know absolutely that alcohol affects our ability to make judgements in a hurry. And we know that they will not cope with an emergency.” Dr Ogden said.
Consider this. When you are driving your car at 65 km/h you are travelling at 50 metres per second. If you react to a hazard – say a vehicle stopped 45 metres ahead of you – the normal reaction time is 1.3 seconds – so you get your foot on the brakes after travelling 24 metres. Your braking distance – in a perfect situation – is 27 metres. That means the total distance travelled from the time you see the emergency is 51 metres. If you are affected by alcohol – even a small dose – a one second delay in reacting to this emergency means you will now travel 75 metres before stopping. You will slam into the stopped vehicle at around 58 km/h. If no one is injured or killed, the crash is not included in road safety statistics. The next time the same crash occurs it might involve a pedestrian with tragic results and of course it will be counted in the road toll. The first crash presented a great opportunity to intervene and prevent a worse result but authorities usually miss such opportunities.
So, next time you think about having ‘one for the road’ – don’t! You can make a difference.