Drunk Driving is considered a serious offense in all the States and the level of intoxication is determined by the level of alcohol in the blood, technically known as Blood Alcohol Content or BAC. This level directly depends on the number of drinks taken by a person before driving a vehicle, which starts showing its effects within a few minutes or an hour, depending on the absorption rate of the individual. Increasing levels of blood alcohol concentration impair a persons ability to drive properly, and also hampers his/her ability to be in charge of a motor vehicle, leading to a possibility of arrest for drunk driving. The allowed legal limit for BAC differs slightly from one state to the other, but each state has severe punishments for offenders.
What is the legal allowed limit for BAC?All states have DUI laws which lay down the legal allowed limits of Blood Alcohol Levels, and anyone exceeding those limits is charged and arrested for drunk driving. Usually the allowed “per se” limit for BAC is set to less than 0.08% in most states and less than 0.04% for commercial drivers. All states follow a “Zero Tolerance” policy for under age drivers, those below the age of 21 years and any one found drunken is charged and arrested immediately. Similarly, there are harsher DUI laws for extremely high levels of BAC, such as those exceeding 0.15% and may be considered as Felony DUI in some states.
According to research and studies, 0.08% may still be a very high limit to be considered as “legally intoxicated” because the effects of alcohol vary from person to person. Some people may show signs of impairment with BAC levels as low as 0.02%, whereas others may show signs of impairment with BAC levels of 0.05% or 0.08%. Despite this, research shows that the probability of being involved in a crash or accident increases rapidly with BAC levels 0.02% or higher.
How is BAC measured?Usually, when a person is stopped as a suspect for drunk driving, the police carry a breath test to determine the Blood Alcohol Concentration. A breathalyzer is used to do it, which is a battery-operated device that takes samples of the breath of the suspect and uses a chemical reaction involving alcohol to produce a colour change and give an estimate of BAC. A BAC Datamaster, Intoxylizer, Intoximeter or a PBT device may be used instead which are all devices to test the alcohol levels. The police may ask for a saliva, urine or blood sample, and the suspect is usually taken to the nearest hospital or to a DUI checkpoint nearby to take samples. A blood test is considered to be most accurate to determine the alcohol levels of a person and is carried out by a qualified medical professional.
The law enforcement official may use various field sobriety tests to check the reflexes of the suspect, but these tests are not used to check the level of alcohol in the blood. A Standardized Field Sobriety Test (SFST) consists of a series of three tests including the horizontal gaze nystagmus, the walk-and-turn and the one-leg stand. A person who fails a field sobriety test but passes the breathalyzer test may still be convicted and charged with a DUI offense.
How to ensure your BAC is under control?You may be able to get an estimate of your Blood Alcohol Level based on the number of drinks you have taken, and by using tools such as a BAC Calculator. Usually, an average 170-pound man must have more than four drinks in an hour on an empty stomach to reach a 0.08% BAC. On the other hand, an average 137-pound woman will need to take three drinks in an hour on an empty stomach to reach and exceed the allowed legal limit of 0.08% BAC. However, the exact number varies from person to person, when other factors come into play, such as a persons metabolism, weight, and amount of food eaten with the drink and so on. So if you plan to party out and drive back home, your best bet would be not to drink and drive at all; and if you plan to take a drink or two, make sure you ask someone to drive you back home or hire a cab.