From the moment cars were invented, we had a problem with people driving drunk. Not long after someone invented the Drunkometer.
Our ancestors were drinking alcohol long before recorded history. There is evidence that suggests humans were drinking 10,000 years ago, and probably long before that. The process of distilling to produce spirits such as vodka, scotch, etc. has been known for 2000 years, but until the 15th century nobody did it. There is evidence to suggest that for centuries in many regions of Europe, people drank beer all day long. And they were probably at some level of intoxication much of the time.
Self-propelled vehicles, i.e. cars, were invented at the end of the 19th century. Cars have been mass produced for about 100 years. Drunkenness could be considered a natural human state. Driving is not.
If you walk or run while drunk, the main way humans have historically traveled, there is a good chance that you will not injure yourself or others significantly. Cars amplify the speed you can travel. If you drive drunk, there is a good chance you will cause significant damage and potentially injure or kill yourself or others. So there is the threat of damage, injury or death and in many instances, the result being damage, injury or death.
The simplified point is that alcohol consumption and cars do not mix. Driving requires skills that diminish with alcohol consumption.
Interestingly, there are studies that show a slight decrease in the probability of having an accident at low blood-alcohol concentration over having no alcohol whatsoever in your body. The probability of having an accident increases marginally between .05 and .08% and then increases dramatically after that. Most of the studies are older and the subjects were people of European ethnic origin.
In Canadian Criminal Law the term used is “impaired by alcohol,” which means that your ability to drive is decreased by virtue of alcohol you consumed. This is different from “affected by alcohol,” which at very low levels could mean you are a marginally better driver. (Don’t try this as some sort of experiment. It is purely a statistical issue and deals with drivers with extremely low amounts of alcohol in their body.)
Because of the threat drinking and driving presents, in Canada there has been criminal law dealing with the problem for decades. The first breath test device to measure alcohol levels for police investigations was called the Drunkometer. It was complex, difficult to use properly and consequently unreliable.
The first Borkenstein Breathalyzers came into use in the mid 1950s and in Canada we were early adopters of the technology. The instrument performed a chemical analysis of the breath sample. When used properly, the Breathalyzer was also very effective for determining the threat posed by drivers at various different blood-alcohol concentrations. It is through studies using the Breathalyzer that scientists concluded that .08mg% alcohol in the blood is an unacceptable level due to the risk of an accident. And it is undisputed that everyone is impaired in their ability to drive at .10%.
The scientific literature as early as 1927 identified mouth-alcohol as perhaps the greatest threat to obtaining an accurate reading from a breath sample. Mouth alcohol will elevate the reading. The devices used at police detachments in Canada will often identify mouth alcohol, but none can fully eliminate the possibility of mouth alcohol, therefore proper procedures must be followed to reduce the risk of a contaminated sample.
The earliest reports stated that mouth alcohol will usually dissipate in 15-20 minutes. More recent studies have shown that alcohol may be present in the mouth up to 40 minutes after consumption.
The Roadside Devices and Mouth Alcohol
The IRP scheme in BC relies on the results from devices that have no function whatsoever to detect the presence of mouth alcohol. As well, the only precaution is to ask the driver when they had their last drink. It is notorious that drivers lie to the police. Indeed, there is no prohibition to lying to the police about your consumption at this stage in an investigation. If you burped or consumed alcohol before blowing into an ASD, the readings would not be reliable. Any alcohol consumed and in the mouth will contaminate the test.
Many people use mouthwash, in some cases in an attempt to mask an odour of liquor. Most mouthwash contains alcohol. If there is alcohol present from the mouthwash, it virtually guarantees an inaccurate, elevated reading.
Mouthwash contamination is common knowledge. Many people contact us and describe having used mouthwash shortly before being stopped and blowing. Our suspicion is that these people have read about it after the incident and are hoping to create a defence. If everyone who claimed to have a mouthwash defence did in fact have an authentic mouthwash defence, British Columbia drivers would have the sweetest breath known to man.
We have never seen a successful dispute of an IRP based on use of mouthwash. On a balance of probabilities, it is simply not believable. (Correction: we found one decision where the driver succeeded on the basis of evidence that he used mouthwash shortly before being stopped. We argued it obviously did a very good job. We have not found any decisions where others were successful with this evidence.)
Unfortunately, some people are probably under .05 and put themselves over on an ASD by trying to mask the odour with mouthwash. Although their actual blood-alcohol concentration is under the limit, the attempt to hide the odour of liquor caused the roadside tester to indicate they were over the limit.
Roadside testers cannot differentiate alcohol from the breath (blood) from alcohol in the mouth. Even if they are functioning properly, there is no guarantee that the results are accurate.
On another day we will discuss what constitutes a proper breath test.