Drunk driving (United States)

fin alcohol-dfa reduced allocation of federal highway funds to any state which refused to raise the age to 21). Unlike DUI cases that involve alcohol, there is no "per se" or legal limit that is employed for persons accused of driving under the influence of prescription medication or illicit drugs. Instead, the key inquiry focuses on whether the driver's faculties were impaired by the substance that was consumed. The detection and successful prosecution of drivers impaired by prescription medication or illegal drugs is therefore quite difficult. Similarly, although urinalysis toxicology screens can detect the presence of such substances in the driver's bloodstream, these analyses are unable to demonstrate that the substance was actually causing impairment at the time of driving. In response to these problems, several jurisdictions are currently considering legislation that would establish "zero tolerance" laws for those drivers arrested for DUI and found to have drugs or medication in their system. Additionally, breathalyzers have been developed for the purpose of administering roadside or laboratory tests that can detect the actual level of a controlled substance in an individual's body.
Many jurisdictions require more serious penalties (i.e., jail time, larger fines, longer DUI program, the installation of ignition interlock devices) in cases where the driver's BAC is over 0.20, or 0.15 in some places. These additional sanctions are an attempt to deter and punish the operation of a vehicle at extremely high BAC levels and the concomitant danger posed to the safety of persons and property by heavily impaired drivers. In many cases, the reason given for these additional sanctions is because an average person would have passed out from that much alcohol. To be able to drive at that level, a person has to have gotten drunk regularly for years, to increase his/her alcohol dfU.S. designate a "per se" blood or breath alcohol level as the threshold point where a person is presumed to be impaired. The most common blood alcohol content (BAC) "legal limit" in the United States is 0.08 (i.e., 80 mg of alcohol in 100 ml of blood). Some states include a lesser charge — often known as driving while impaired — at a BAC of, say, 0.05 or above but less than the legal limit for the more serious charge. Prior to wider emphasis on drinking and driving in the 1980s, standards of 0.12 were also in place in some states. The legal limit for aircraft pilots and commercial drivers in the U.S. is set at 0.04. All states also observe a much stricter standard — known in some of them as "TCP," standing for "Trace Constitutes Positive" — for drivers under the age of 21, which, since 1989, has been the uniform minimum purchase age for alcoholic beverages throughout the nation (prior to that year about half of all U.S. states formerly observed a lower drinking age, most commonly 18; the trend toward raising the age commenced in the late 1970s, with much of the impetus for doing so provided by a federal law passed in the mid-1980s mandating a reduced allocation of federal highway funds to any state which refused to raise the age to 21).
Unlike DUI cases that involve alcohol, there is no "per se" or legal limit that is employed for persons accused of driving under the influence of prescription medication or illicit drugs. Instead, the key inquiry focuses on whether the driver's faculties were impaired by the substance that was consumed. The detection and successful prosecution of drivers impaired by prescription medication or illegal drugs is therefore quite difficult. Similarly, although urinalysis toxicology screens can detect the presence of such substances in the driver's bloodstream, these analyses are unable to demonstrate that the substance was actually causing impairment at the time of driving. In response to these problems, several jurisdictions are currently considering legislation that would establish "zero tolerance" laws for those drivers arrested for DUI and found to have drugs or medication in their system. Additionally, breathalyzers have been developed for the purpose of administering roadside or laboratory tests that can detect the actual level of a controlled substance in an individual's body.

Many jurisdictions require more serious penalties (i.e., jail time, larger fines, longer DUI program, the installation of ignition interlock devices) in cases where the driver's BAC is over 0.20, or 0.15 in some places. These additional sanctions are an attempt to deter and punish the operation of a vehicle at extremely high BAC levels and the concomitant danger posed to the safety of persons and property by heavily impaired drivers. In many cases, the reason given for these additional sanctions is because an average person would have passed out from that much alcohol. To be able to drive at that level, a person has to have gotten drunk regularly for years, to increase his/her alcohol tolerance, and therefore is likely to have driven drunk repeatedly. However, since there is currently no standard test to measure alcohol tolerance, proponents of high-BAC additional penalties point to some studies that indicate that high-BAC offenders are more likely to be involved in a crash and more likely to recidivate. Critics of such laws point out that, due to the wide variation of alcohol tolerance, people with a high tolerance will suffer the additional penalties, even though they may be much less impaired than people with a low tolerance that were driving with a much lower BAC.
Some U.S. states also increase the penalties for drunk driving (even to the point of making it a felony) if certain other aggravating circumstances besides a very high BAC are present, such as if the drunk driver caused an accident requiring the hospitalization of another person lasting greater than a specified period of time (often 72 hours), in cases where an accident resulted in property damage exceeding a certain amount (often $500), or where the driver has prior (and relatively recent) convictions for drunk driving. In addition, most states observe administrative laws that further penalize people convicted of DUI, typically enforced by the department that issues driver's licenses, usually titled Department of Motor Vehicles (DMV), or Department of Licensing. Also, in many states, persons under 21 who purchase, or even attempt or conspire to purchase, alcohol can have their driving privileges suspended (if they already are licensed drivers) or delayed (if not) even if they were not caught actually driving while intoxicated.
==History of drunk dfs*reciting all or part of the alphabet.

• FSTs are better at determining the level of impairment than they are at estimating the driver's BAC.

The (US) National Highway Traffic Safety Administration has scientifically determined that three FSTs are statistically reliable in detecting impaired drivers. These three "standardized" tests (SFSTs) are the "Walk and Turn" test, the "One-leg Stand" and "Horizontal Gaze Nystagmus" in which a law enforcement officer observes the discrete movements of a person's eyes when tracking a stimulus across their field of vision.

Chemical test

If arrested, the sfwhen the vehicle was actually operated, in the case of a driver who drank a large volume immediately before driving.

If it is determined that the person is not legally intoxicated, they might be released without any charges. However, many jurisdictions have charges which don't require a particular BAC, and tests for some drugs (such as GHB) will not show up in a test designed for alcohol.
Most of the time, the driver will either be kept in a holding cell (the "drunk tank") until they are deemed sober enough to be released, or sent to jail to wait for their first court hearing (or until they can get bailed out).