Blood alcohol concentration is the measurement of the amount of alcohol that is in an individual’s bloodstream. Breath alcohol concentration is the measurement of the amount of alcohol in an individual’s breath.
The phrase blood alcohol content may also be called blood alcohol concentration or blood alcohol level. In addition, the phrase breath alcohol content may also be called breath alcohol concentration or breath alcohol level.
All of these phrases are referred to, in their abbreviated form, as BAC. The amount of alcohol that is in an individual’s bloodstream is measured in milligrams (mg) of alcohol per 100 milliliters (ml) of blood.
This number is usually expressed as a percentage, for example, 0.08 or 0.15. If an individual has a BAC of .10 percent, their blood supply contains one part alcohol per every 1,000 parts blood.
Levels of blood alcohol concentration are determined through blood testing. An individual’s level of impairment may also be measured using breath alcohol concentration.
Breath alcohol concentration is an indirect, or approximate, measure of blood alcohol concentration. Breath alcohol concentration is measured using a breath analyzer, typically referred to as a breathalyzer.
When an individual takes a breathalyzer test, they exhale into a breath analyzer. There are a series of chemical reactions that result in the breath ethanol, the intoxicating agent found in alcoholic beverages, being converted to an electric current.
The amount of current that is produced is then displayed on the breathalyzer device as well as the individual’s breach alcohol concentration, which is also expressed as a percentage.
What Constitutes Drunk Driving or Driving While Intoxicated?
Blood alcohol content (BAC) is the most commonly used metric to determine the level of alcohol concentration in an individual’s body. In every state, except for Arizona, the legal limit for adults over the age of 21 is a BAC level of .08%.
In the State of Arizona, an individual may be charged and convicted of driving under the influence with any level of alcohol in their body if an individual is impaired to the slightest degree, pursuant to A.R.S. 28- 1381 (A) (1).
An experienced criminal defense attorney is well-equipped to fight DWI or DUI charges which protect the rights of their clients. If an individual has been charged with a drunk driving offense, they should not wait to contact an attorney.
A defendant, or individual who is charged with a criminal offense, will be dealing with the court system as well as the Department of Motor Vehicles (DMV). Your attorney will be able to represent an individual in front of both entities while providing guidance throughout the entire process.
What is the Difference Between DWI and DUI?
The terms Driving While Intoxicated (DWI) and Driving Under the Influence (DUI) are often interchangeably used. Some states, however, classify DWI and DUI offenses separately, with DWI typically being the more serious charge.
DUI may also mean an individual was driving under the influence of drugs, which is also taken very seriously. There are other states that use different terms to refer to drunk driving, which may include:
- Operating under the influence (OUI);
- Operating a vehicle under the influence (OVI);
- Driving while ability impaired (DWAI);
- Operating a vehicle under the influence of an intoxicant (OVUII); and
- Driving under the influence of intoxicants (DUII).
What is Preliminary Alcohol Screening?
If an individual is pulled over by law enforcement on suspicion of drunk driving (DUI), the law enforcement officer will conduct a series of tests to determine whether or not they have probable cause to arrest the driver. The tests used to determine this are referred to as field sobriety tests.
Field sobriety tests include:
- Horizontal Gaze Nystagmus: The law enforcement officer holds a pen or light about 12 inches from the driver’s face and asks the driver to follow it with their eyes;
- Standing on one foot: The officer may ask the driver to count while doing this;
- Walking an imaginary line: The officer will ask the driver to follow an imaginary line for several steps and then asks them to turn around and walk back, all heel-to-toe;
- Finger-to-nose: the officer will ask the driver to close his eyes and, with both arms extended, touch a finger to their nose; and
- Reciting sections of the alphabet.
One of the more well known field sobriety tests is the preliminary alcohol screening (PAS) device, commonly referred to as a breathalyzer.
How Do Preliminary Alcohol Screening Devices Work?
Alcohol in an individual’s system is measured by the BAC, or blood alcohol content. As noted above, this is the percentage of alcohol in an individual’s blood.
As an individual drinks alcohol, it is not just digested in their stomach, but instead, is absorbed in their mouth, throat, and lungs. The amount of alcohol that remains in the membrane of an individual’s lungs is relative to the amount of the alcohol in their blood.
Do I have to Take a Preliminary Alcohol Screening Test?
In general, preliminary alcohol screening tests are voluntary. An individual who is pulled over on suspicion of drunk driving is not required to submit to these tests.
This, however, will depend on where an individual lives and how old they are. In Florida, for example, a driver is not necessarily required to submit to a PAS test.
However if they do not, their driver’s license will be suspended for at least 90 days until hardship can be demonstrated. In California, a driver who is 21 years of age or older may decline to take a PAS test without consequences.
However, individuals who are 21 years of age are older will face an automatic suspension.
Are Preliminary Alcohol Screening Results Accurate?
If properly used, if a device is calibrated correctly, the results of a preliminary alcohol screening (PAS) test are generally accurate, but not precise. Studies indicate that the average variance in testing results from this type of device is about 15% higher than the actual BAC.
Because of this potential for inaccuracy in addition to the risk that a juror may believe this test is unquestionably accurate, there are many states and courts that do now allow PAS evidence to be introduced at trial. Therefore, the results of a PAS test serve the sole purpose of providing a law enforcement officer with more concrete cause to arrest an individual for drunk driving as well as to perform a more accurate sobriety test at the station.
What Factors are Taken into Consideration in Issuing Penalties for DWI/DUI Intoxication?
The states will vary in how the penalties for a DWI/DUI conviction are determined. Penalties may include:
- License suspension or revocation;
- Steep fines;
- Jail or prison time;
- Home confinement;
- Installing an ignition interlock device on their vehicle; and
- Community service.
When making a determination regarding the penalties issued to a defendant, a court will typically consider the following factors:
- Prior conviction history;
- Whether injury or death occurred as a result of the DWI;
- Whether any property damage occurred;
- Whether the individual was driving a commercial vehicle;
- If the driver was age 21 or over at the time of arrest; and
- Whether or not there was a minor in the car at the time of the individual’s arrest.
Should I Seek Legal Help?
If you have been arrested for a DWI, DUI, or a similar alcohol related offense where you submitted to chemical testing, it may be in your best interests to consult a DUI/DWI lawyer immediately. Your attorney can assist you with protecting your rights as well as to ensure that any testing was done properly and lawfully.
