Stopped for Drunken Driving? Certain Physical Factors can Affect a Driver’s Blood-alcohol Content (BAC) Reading

It’s no surprise that drivers in the Garden State face stiff and relatively inflexible drunk driving laws. And while saying that our state’s anti-DWI statutes are rigid, it’s a fair bet that the State Police and local law enforcement officers who uphold those laws are equally as unwavering in carrying out their duties when it comes to motorists who allegedly drive under the influence of beer, wine or hard liquor.

Naturally, nobody actually wants to be arrested for DWI or drug DUI, but the fact remains that it does happen and one should be ready for that day, if it comes, by understanding the science surrounding a drunken driving arrest.

Following a traffic stop, if the driver seems even slightly impaired, a patrolman may decide that the motorist has a high likelihood of being drunk behind the wheel. After confirming his or her suspicions, usually through as well as with a battery of standardized field sobriety tests, the officer may take the suspect into custody. Once at police headquarters, the driver will likely be asked to submit to a breathalyzer test.

Many people are nervous about taking such a test, if only because they believe the evidence provided by the machine, such as an Alcotest device, is incontrovertible and damning beyond measure. As New Jersey DWI defense attorneys, I and my staff know that the blood-alcohol concentration (BAC) readings produced by these machines are only a “snapshot” of an individual’s so-called drunkenness.

It’s important to realize that many factors are at play when determining if a specific individual is legally drunk. Some of the more critical human factors that affect a BAC reading include body weight, time since one’s last drink, quantity and type of food recently consumed along with the alcohol, as well as others.

Right off the bat, it’s important to state that no matter how “good” one may feel after consuming alcohol, a person should never attempt to operate a car, truck or other motor vehicle simply on the basis that they “feel” sober. Drunken driving laws what they are, even trace amounts of alcohol in one’s bloodstream can complicate the legal fallout of what might have been just a simple or routine traffic stop.

So let’s take a look at some of those factors that affect BAC readings following a DWI arrest:

Body Weight/Mass
It has been well established that alcohol has what scientists call an “affinity” for water. Anyone who has even used fuel line anti-freeze knows that the alcohol in that product helps to absorb water in a gas tank, so that it can be safely carried through the fuel system, into the engine and out the tailpipe. This same effect takes place in the human body when a person drinks an alcoholic beverage.

Body fat is composed of a fair amount of water. Given similar amounts of alcohol consumed, a thinner, leaner individual will tend to have a lower BAC reading than heavy person since the alcohol has less opportunity to be stored in a thin person’s body. Alternately, comparing a small-framed individual to one who is larger (given the same quantity of alcohol consumed), the larger person will typically have a lower BAC reading, simply because their body mass is higher and the alcohol will be more widely “distributed.”

When one considers these albeit seemingly contradictory factors, a taller yet more muscular person has the best chance for a lower BAC reading than a smaller, lighter individual who has a larger percentage of fat on his or her frame.

Male or Female?
Unfortunately, the fairer sex tends to lose out when it comes to BAC readings, all other factors being equal. Medically speaking, the average female has more natural fat in their bodies than a typical male; therefore, comparing a woman and a man of similar height, weight and fitness, if they both consume equal amounts of alcohol, the woman will likely show a higher BAC reading than her male counterpart. However, the good news for ladies is that their bodies tend to eliminate alcohol at a faster rate than men, which give them a slight advantage.

When and How Much Did You Eat?
One of the factors that can essentially delay the absorption of alcohol into one’s system is the existence of food in the body. Because having food in one’s stomach can not only delay alcohol absorption, but also delay the time it takes for a BAC reading to “peak,” it can be advantageous to have eaten a large dinner or lunch prior to having one’s BAC measured. Snacking while drinking has also been known to contribute to a delayed BAC peak.

Of course, there are numerous other factors — such as alcohol tolerance and the type of drinks one has consumed prior to a traffic stop — that will ultimately influence a BAC reading at police headquarters. The easiest step in avoiding a DWI arrest would naturally be not to drink at all. But human nature being what it is, that course of action is rarely followed.

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