The amount of alcohol in your bloodstream is called your Blood Alcohol Concentration or BAC.
Your BAC depends on how much you drink. The more you drink, the higher your BAC. But there are also many other factors that affect your BAC such as your size, your weight, your gender, whether you’ve eaten and even how tired you are. BAC can be measured with a breathalyzer or by analyzing a sample of blood. It is measured by the number of grams of alcohol in 100ml of blood. For example, a BAC of .08, the US legal limit for driving for those over 21, means you have .08 grams of alcohol in every 100ml of blood.
Alcohol’s effect on the brain slows down a person’s reaction times – they take longer to respond to hazards. So, if a cat ran in front of a car or motorbike, the delay between you seeing it and putting your foot on the brake slows down. The extra distance traveled in that time is called your ’thinking distance’.
Each drink can increase the ‘thinking distance’ by 20%. The risk of someone being in an accident increases by: two times for drivers with a BAC of .05 four times for drivers with a BAC of .08 and twenty times for drivers with a BAC of .15. Drivers who have been drinking also underestimate the distance and speed of other vehicles on the road. Their vision is affected, slowing reaction times further. Drivers who’ve been drinking also overestimate their ability and drive more recklessly too.
In the United States, all states define driving with a blood alcohol concentration (BAC) at or above .08 as a crime, but specific laws and penalties vary substantially from state to state, with some states having specific BAC limits for commercial drivers and drivers who have previous DUI offenses.
Blood Alcohol Level
42 states, the District of Columbia, the Northern Mariana Islands and the Virgin Islands have administrative license suspension (ALS) on the first offense. ALS allows law enforcement to confiscate a driver’s license for a period of time if he fails a chemical test. Most of these states allow limited driving privileges (such as to/from work).
All states have some type of ignition interlock law, in which judges require all or some convicted drunk drivers to install interlocks in their cars to analyze their breath and disable the engine if alcohol is detected. 20 states (and 4 California counties) have made ignition interlocks mandatory or highly incentive for all convicted drunk drivers, even first-time offenders. Legal pr knows the value of media exposure, how to get it, and most important how to leverage it to minimize drunken drivers.