| DWI - Driving While Intoxicated. | | | | (commonly written as .08) or more is considered |
| DUI - Driving Under the Influence (of alcohol or | | | | illegal. However, the officer on patrol certainly |
| drugs). | | | | doesn't have a medical lab in the car, and must |
| BAC - Blood Alcohol Concentration (or Content). | | | | rely on a breath testing device. |
| These three acronyms form a deadly | | | | The brand name Breathalyzer is often used |
| combination. The main links between the three | | | | generically to describe devices that measure blood |
| are alcohol and driving. It is well documented that | | | | alcohol concentration. This type of breath analyzer |
| drinking alcohol impairs judgment, slows reaction | | | | does not actually measure the concentration of |
| time, and decreases coordination. When a person | | | | alcohol in the blood. Instead, the reading on the |
| is DWI or DUI, he or she is piloting a one-ton time | | | | breath analyzer is only an estimate of the alcohol |
| bomb with little control over it. Is it speeding | | | | in the blood. |
| towards you? | | | | Correlations between the amount of alcohol in the |
| These three acronyms have legal ramifications | | | | blood and the resulting amount of alcohol in the |
| too. DUI and DWI are criminal offenses. To | | | | breath have been made. The tests show the ratio |
| determine if a DWI or DUI offense has been | | | | to be approximately 2100 (in the blood) to about |
| committed, it is necessary to measure how much | | | | 1 (in the breath), or 2100:1. Based on factors listed |
| alcohol was consumed by the suspect driver (the | | | | above, a person's blood:breath alcohol ratio can |
| BAC). | | | | vary from 1700:1 to 2400:1. |
| In the field, police officers utilize tests to | | | | In simpler terms, if an average person has 2100 |
| determine the amount of a driver's impairment | | | | drops of alcohol in the blood, the breath tester will |
| due to alcohol. Such tests include, but are not | | | | show a reading of 1 drop. Doctors have |
| limited to, breath alcohol tests and field sobriety | | | | measured the blood and breath alcohol contents |
| tests. The breath test is further discussed in this | | | | of test subjects simultaneously, allowing them to |
| article. | | | | calculate the relationship between alcohol in the |
| A person's reaction to alcohol varies widely. Some | | | | blood and alcohol in the breath. |
| factors that affect alcohol impairment include | | | | When a drunk driving suspect blows into the |
| gender, body weight, time of last meal, time of | | | | breath alcohol tester, the machine measures the |
| day, alcohol tolerance, medications, genetics, rate | | | | alcohol in the breath. The machine then calculates |
| of alcohol consumption, and many more. | | | | the amount of alcohol in the blood by using a |
| A police officer stopping a suspected drunk driver | | | | blood:breath alcohol ratio. This calculation of BAC is |
| has visual, olfactory (smell), and breath tests to | | | | only an estimate. However, that estimate is what |
| judge a person's impairment from alcohol. The | | | | goes on the police report and is what the judge |
| officer must make some kind of quantitative | | | | will see. |
| determination of the amount of alcohol | | | | The next time you have consumed alcohol and |
| impairment at the time of the stop. All the | | | | feel like you are not impaired to drive, remember |
| factors mentioned above do not matter to the | | | | these points. First, your confidence may be simply |
| officer. All he or she wants to do is to create a | | | | alcohol-induced euphoria. Second, your life and the |
| "snapshot" of the degree of impairment. | | | | lives of those you drive near may all depend on |
| Blood alcohol concentration (BAC) is a measure of | | | | what the little breath machine thinks is normal. |
| the amount of alcohol in the blood, expressed as | | | | Are you willing to bet your freedom on the |
| a percentage by volume. This can be measured | | | | opinion of some fancy calculator? Me neither. Be |
| precisely by taking a sample of the driver's blood | | | | safe! |
| for analysis. In the U.S., a BAC level of 0.08% | | | | |