Before starting out on defensive driving technique #4, we should define “unsound”. The definition of “unsound” according to the Random House Unabridged Dictionary is “defective, decayed, impaired or damaged.” When used in the context of driving, “unsound” means that an element exists which reduces a driver’s capability of safely controlling their vehicle.

Alcohol & Drugs: The #1 Cause of Driving Impairment.

If ever there was a defensive driving technique which should be automatically adopted by all drivers, it is “don’t drink and drive”. Strangely enough, that’s not the case!

One of the most common causes of driving in an “unsound” state is alcohol. Alcohol is a depressant, and begins to reduce a person’s faculties with the very first drink. It is a proven fact that even blood alcohol levels that are way under the “legal limit,” cause impairment of a driver’s physical and mental capabilities.

In the USA, all states now have a legal level of .08%. With this level of alcohol concentration in the blood, a driver is presumed to be legally “impaired”, and no other evidence is needed. In other countries the alcohol level concentration is lower. In Australia for example it is .05%. However, driving skills often begin to deteriorate at alcohol concentration levels as low as .04%—less than half the “legal limit” in the US. Not only that, alcohol in a driver’s system acts on the very skills and abilities most needed: vision, judgment, and the ability to handle more than one thing at a time.

Alcohol works quickly to slow down your mind and motor skills, causing a profound effect on reaction times. For example, if a driver’s reaction time is doubled when traveling at 70 mph, the result would mean that driver taking an additional 103 feet to stop. A substantial time difference like this could easily cause a collision which otherwise might have been avoided.

Other Causes of Driving Impairment

Whilst alcohol or drugs is the most obvious cause for driving in an “unsound” state, there are a number of other impairments which could have strikingly similar outcomes. Driving whilst fatigued, or with disabling injuries and illness can cause just as much havoc to a driver’s capability. Similarly, disastrous results can also occur from the effects of prescribed medication.

In Australia, there is a campaign to stop drivers from driving fatigued, which features the slogan “Stop. Revive. Survive”. Encouraging drivers to stop for a break, walk around, drink some coffee or tea and just break the “highway hypnosis” syndrome is a very wise defensive driving technique to highlight in this way.

Questions To Ask Yourself Before Driving

Everyone driving on our roads must take responsibility for their own actions. As drivers, we are all obliged to ensure we are capable of driving efficiently with all our faculties working properly. Questions to ask yourself include

- Am I in a fit condition to drive?
- Am I rested?
- Are all my limbs in proper working order?
- Am I feeling ill?
- Have I taken medication that might impair my reflexes and focus?
- How long since I had an alcoholic drink? Has that drink worked its way through my system yet?
- Am I wearing my spectacles?”

Only if you can answer yes to all these questions should you buckle on your seat belt and begin to drive your car. Satisfying yourself that all answers are in the affirmative is a very effective defensive driving technique, and one which you should make into an automatic habit.

In our defensive driving technique series so far we have covered four vital elements. They are

1. Pay attention
2. Always wear a seat belt
3. Don’t trust anyone except yourself
4. Do not drive when “unsound” or impaired.

If all drivers used just these four defensive driving techniques (and there are many more) there would be no fatal accidents, everyone would survive traffic collisions. Practiced habitually, most of the serious collisions would be eliminated, and many thousands of lives would be saved each year.

The reality is however, that we are all human, and will always make mistakes that end up in traffic accidents and collisions. So practice the defensive driving technique of never driving in an “unsound” state, either from alcohol, drugs, medications, injury and illness or fatigue. These ideas are the foundation of driving safely and staying out of trouble on the roads.