Driving under the influence (DUI) is the
crime
In ordinary language, a crime is an unlawful act punishable by a State (polity), state or other authority. The term ''crime'' does not, in modern criminal law, have any simple and universally accepted definition,Farmer, Lindsay: "Crime, definiti ...
of
driving
Driving is the controlled operation and movement of a land vehicle, including cars, motorcycles, trucks, and buses. A driver's permission to drive on public highways is granted based on a set of conditions being met, and drivers are required to ...
, operating, or being in control of a
vehicle
A vehicle () is a machine designed for self-propulsion, usually to transport people, cargo, or both. The term "vehicle" typically refers to land vehicles such as human-powered land vehicle, human-powered vehicles (e.g. bicycles, tricycles, velo ...
while one is impaired from doing so safely by the effect of either
alcohol
Alcohol may refer to:
Common uses
* Alcohol (chemistry), a class of compounds
* Ethanol, one of several alcohols, commonly known as alcohol in everyday life
** Alcohol (drug), intoxicant found in alcoholic beverages
** Alcoholic beverage, an alco ...
(see
drunk driving
Drunk driving (or drink-driving in British English) is the act of driving under the influence of alcohol. A small increase in the blood alcohol content increases the relative risk of a motor vehicle crash.
In the United States, alcohol is in ...
) or some other
drug
A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via insufflation (medicine), inhalation, drug i ...
, whether
recreational or
prescription (see
drug-impaired driving). Multiple other terms are used for the offense in various jurisdictions.
Terminology
The name of the offense varies from jurisdiction to jurisdiction and from legal to colloquial terminology. In various jurisdictions the offense is termed "driving under the influence"
f alcohol or other drugs
F, or f, is the sixth letter of the Latin alphabet and many modern alphabets influenced by it, including the modern English alphabet and the alphabets of all other modern western European languages. Its name in English is ''ef'' (pronounc ...
(DUI), "driving under the influence of intoxicants" (DUII), "driving while impaired" (DWI), "impaired driving", "driving while intoxicated" (DWI), "operating while intoxicated" (OWI), "operating under the influence" (OUI), "operating
vehicle under the influence" (OVI), "drunk in charge", or "over the prescribed limit" (OPL) (in the UK). Alcohol-related DUI is referred to as "drunk driving", "drunken driving", or "drinking and driving" (US), or "drink-driving" (UK/Ireland/Australia). Cannabis-related DUI may be termed "driving high", and more generally drug-related DUI may be referred to as "drugged driving", "driving under the influence of drugs" (DUID), or "drug-impaired driving".
In the United States, the specific
criminal offense is usually called driving under the influence, but states may use other names for the offense including "driving while intoxicated" (DWI), "operating while impaired" (OWI) or "operating while ability impaired", and "operating a vehicle under the influence" (OVI).
Definition
In typical usage of the terms DUI, DWI, OWI, and OVI, the offense consists of driving a vehicle while affected by alcohol or drugs. However,
in the majority of US states, the criminal offense may not involve actual driving of the vehicle but rather may broadly include ''operating'' or being physically ''in control'' of a motor vehicle while under the influence, even if the person charged is not in the act of driving.
For example, individuals found in the
driver's seat of a car while intoxicated and holding the car keys, even while parked, may be charged with DUI because they are in control of the vehicle. In contrast, California only makes it illegal to ''drive'' a motor vehicle while under the influence, requiring actual "driving". "The distinction between these two terms is material, for it is generally held that the word 'drive,' as used in statutes of this kind, usually denotes movement of the vehicle in some direction, whereas the word 'operate' has a broader meaning so as to include not only the motion of the vehicle but also acts which engage the machinery of the vehicle that, alone or in sequence, will set in motion the motive power of the vehicle."
Many DUI laws also apply to
motorcycling
Motorcycling is the act of riding a motorcycle. For some people, motorcycling may be the only affordable form of individual motorized transportation, and small-engine displacement, displacement motorcycles are the most common motor vehicle in ...
,
boating
Boating is the leisurely activity of travelling by boat, or the recreational use of a boat whether powerboats, sailboats, or man-powered vessels (such as rowing and paddle boats), focused on the travel itself, as well as sports activities, suc ...
, piloting
aircraft
An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...
, use of mobile
farm machinery
Agricultural machinery relates to the machine (mechanical), mechanical structures and devices used in farming or other agriculture. There are list of agricultural machinery, many types of such equipment, from hand tools and power tools to tractor ...
such as
tractor
A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a Trailer (vehicle), trailer or machinery such as that used in agriculture, mining or constructio ...
s and
combine harvester
The modern combine harvester, also called a combine, is a machine designed to harvest a variety of cultivated seeds. Combine harvesters are one of the most economically important labour-saving inventions, significantly reducing the fraction of ...
s,
riding horses or driving a
horse-drawn vehicle
A horse-drawn vehicle is a piece of equipment pulled by one or more horses. These vehicles typically have two or four wheels and were used to carry passengers or a load. They were once common worldwide, but they have mostly been replaced by auto ...
,
cycling
Cycling, also known as bicycling or biking, is the activity of riding a bicycle or other types of pedal-driven human-powered vehicles such as balance bikes, unicycles, tricycles, and quadricycles. Cycling is practised around the world fo ...
, or
skateboarding
Skateboarding is an extreme sport, action sport that involves riding and Skateboarding trick, performing tricks using a skateboard, as well as a recreational activity, an art form, an entertainment industry Profession, job, and a method of tr ...
, possibly with different
BAC level than regular driving. In some jurisdictions, there are separate charges depending on the vehicle used. In Washington state, for instance, BUI (bicycling under the influence) laws recognize that intoxicated cyclists are likely to primarily endanger themselves. Accordingly, law enforcement officers are empowered only to protect the cyclist by impounding the bicycle rather than filing DUI charges.
George Smith, a
London Taxi
A hackney or hackney carriage (also called a cab, black cab, hack or taxi) is a carriage or car for hire. A hackney of a more expensive or high class was called a remise. A symbol of London and Britain, the black taxi is a common sight on t ...
cab driver
A taxi, also known as a taxicab or simply a cab, is a type of vehicle for hire with a Driving, driver, used by a single passenger or small group of passengers, often for a non-shared ride. A taxicab conveys passengers between locations of thei ...
, ended up being the first person to be convicted of driving a motor vehicle while intoxicated, on September 10, 1897, under the "drunk in charge" provision of the
1872 Licensing Act. He was fined 25
shillings
The shilling is a historical coin, and the name of a unit of modern currencies formerly used in the United Kingdom, Australia, New Zealand, other British Commonwealth countries and Ireland, where they were generally equivalent to 12 pence ...
, which is .
Alcohol

Drunk driving (or drink-driving in British English) is the act of driving under the influence of
alcohol
Alcohol may refer to:
Common uses
* Alcohol (chemistry), a class of compounds
* Ethanol, one of several alcohols, commonly known as alcohol in everyday life
** Alcohol (drug), intoxicant found in alcoholic beverages
** Alcoholic beverage, an alco ...
. A small increase in the
blood alcohol content
Blood alcohol content (BAC), also called blood alcohol concentration or blood alcohol level, is a measurement of alcohol intoxication used for legal or medical purposes.
BAC is expressed as mass of alcohol per volume of blood. In US and many i ...
increases the
relative risk
The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Together with risk difference and odds ratio, relative risk measures the association bet ...
of a motor vehicle crash.
In the United States, alcohol is involved in 30% of all
traffic fatalities. It is not known nationally how many people are killed each year in crashes involving drug-impaired drivers because of data limitations, but one study of drivers who were seriously injured in crashes found that 23.6% of drivers were positive for alcohol and 12.2% were positive solely for alcohol.
Other drugs
For drivers suspected of
drug-impaired driving, drug testing screens are typically performed in scientific laboratories so that the results will be admissible in evidence at trial. Due to the overwhelming number of impairing substances that are not alcohol, drugs are classified into different categories for detection purposes. Drug impaired drivers still show impairment during the battery of standardized field sobriety tests, but there are additional tests to help detect drug impaired driving. In the US, one study found that 25.8% of drivers seriously injured in crashes tested positive for cannabinoids, 13.6% tested positive solely for cannabinoids, and 24.6% tested positive for a drug other than alcohol or cannabis.
Recreational drugs
Drivers who have smoked or otherwise consumed
cannabis
''Cannabis'' () is a genus of flowering plants in the family Cannabaceae that is widely accepted as being indigenous to and originating from the continent of Asia. However, the number of species is disputed, with as many as three species be ...
products such as
marijuana
Cannabis (), commonly known as marijuana (), weed, pot, and ganja, List of slang names for cannabis, among other names, is a non-chemically uniform psychoactive drug from the ''Cannabis'' plant. Native to Central or South Asia, cannabis has ...
or
hashish
Hashish (; ), usually abbreviated as hash, is a Compression (physics), compressed form of resin (trichomes) derived from the cannabis flowers. European Monitoring Centre for Drugs and Drug Addiction, Lisbon, As a Psychoactive drug, psychoactive ...
can be charged and convicted of impaired driving in some jurisdictions. A 2011 study in the ''B.C. Medical Journal'' stated that there "...is clear evidence that cannabis, like alcohol, impairs the psychomotor skills required for safe driving." The study stated that while "
nnabis-impaired drivers tend to drive more slowly and cautiously than drunk drivers,... evidence shows they are also more likely to cause accidents than drug and alcohol-free drivers".
A more recent 2023 study found that when compared to alcohol, "the impairment effect of marijuana on driving is relatively mild" since drivers using cannabis "drive slower, avoid overtaking other vehicles, and increase following distances." In Canada, police forces such as the
Royal Canadian Mounted Police
The Royal Canadian Mounted Police (RCMP; , GRC) is the Law enforcement in Canada, national police service of Canada. The RCMP is an agency of the Government of Canada; it also provides police services under contract to 11 Provinces and terri ...
have "...specially trained drug recognition and evaluation
REofficers...
hocan detect whether or not a driver is drug impaired, by putting suspects through physical examinations and co-ordination tests.
In 2014, in the Canadian province of Ontario, Bill 31, the Transportation Statute Law Amendment Act, was introduced to the provincial legislature. Bill 31 contains driver's license "...suspensions for those caught driving under the influence of drugs, or a combination of drugs and alcohol.
Ontario police officers "...use
Standard Field Sobriety Tests (SFSTs) and drug recognition evaluations to determine whether the officer believes the driver is under the influence of drugs."
In the province of Manitoba, an "...officer can issue a physical coordination test. In B.C., the officer can further order a drug recognition evaluation by an expert, which can be used as evidence of drug use to pursue further charges."
In the US state of Colorado, the state government indicates that "
y amount of marijuana consumption puts you at risk of driving impaired." Colorado law states that "drivers with five nanograms of active
tetrahydrocannabinol
Tetrahydrocannabinol (THC) is a cannabinoid found in cannabis. It is the principal psychoactive constituent of ''Cannabis'' and one of at least 113 total cannabinoids identified on the plant. Although the chemical formula for THC (C21H30O2) de ...
(THC) in their whole blood can be prosecuted for driving under the influence (DUI). However, no matter the level of THC, law enforcement officers base arrests on observed impairment." In Colorado, if consumption of marijuana is impairing your ability to drive, "it is illegal for you to be driving, even if that substance is prescribed
y a doctoror legally acquired."
Prescription medications
Prescription medications such as opioids and
benzodiazepine
Benzodiazepines (BZD, BDZ, BZs), colloquially known as "benzos", are a class of central nervous system (CNS) depressant, depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed t ...
s often cause side effects such as excessive drowsiness, and, in the case of opioids, nausea. Other prescription drugs including antiepileptics and antidepressants are now also believed to have the same effect.
In the last ten years, there has been an increase in motor vehicle crashes, and it is believed that the use of impairing prescription drugs has been a major factor.
Workers are expected to notify their employer when prescribed such drugs to minimize the risk of motor vehicle crashes while at work.
If a worker who drives has a health condition which can be treated with
opioids
Opioids are a class of Drug, drugs that derive from, or mimic, natural substances found in the Papaver somniferum, opium poppy plant. Opioids work on opioid receptors in the brain and other organs to produce a variety of morphine-like effects, ...
, then that person's doctor should be told that driving is a part of the worker's duties and the employer should be told that the worker could be treated with opioids.
[, which cites
*] Workers should not use impairing substances while driving or operating
heavy machinery like
forklift
A forklift (also called industrial truck, lift truck, jitney, hi-lo, fork truck, fork hoist, and forklift truck) is a powered industrial truck used to lift and move materials over short distances. The forklift was developed in the early 20th c ...
s or
cranes.
If the worker is to drive, then the health care provider should not give them opioids.
If the worker is to take opioids, then their employer should assign them work which is appropriate for their impaired state and not encourage them to use safety sensitive equipment.
Testing
Field sobriety testing
Field sobriety tests are a battery of tests used by
police officer
A police officer (also called policeman or policewoman, cop, officer or constable) is a Warrant (law), warranted law employee of a police, police force. In most countries, ''police officer'' is a generic term not specifying a particular rank. ...
s to determine if a person suspected of impaired driving is intoxicated with alcohol or other drugs. FSTs are primarily used in the United States, to meet "
probable cause for arrest" requirements (or the equivalent), necessary to sustain a DWI or DUI conviction based on a chemical blood alcohol test. In the US, field sobriety tests are voluntary; however, some states mandate commercial drivers accept preliminary breath tests (PBT).
Drug Evaluation and Classification program
The Drug Evaluation and Classification program is designed to detect a drug impaired driver and classify the categories of drugs present in his or her system. The procedures are used post-arrest to gather evidence for trial, rather than for probable cause, as they would be difficult to conduct at the scene.
Initially developed by the Los Angeles, California, Police Department in the 1970s, the DEC program breaks down detection into a twelve-step process that a government-certified Drug Recognition Expert (DRE) can use to determine the category or categories of drugs that a suspect is impaired by. The twelve steps are:
#Breath Alcohol Test
#Interview with arresting officer (who notes slurred speech, alcohol on breath, etc.)
#Preliminary evaluation
#Evaluation of the eyes
#Psychomotor tests
#Vital signs
#Dark room examinations
#Muscle tone
#Injection sites (for injection of
heroin
Heroin, also known as diacetylmorphine and diamorphine among other names, is a morphinan opioid substance synthesized from the Opium, dried latex of the Papaver somniferum, opium poppy; it is mainly used as a recreational drug for its eupho ...
or other drugs)
#Interrogation of suspect
#Opinion of the evaluator
#Toxicological examination
DREs are qualified to offer expert testimony in court that pertains to impaired driving on drugs.
The DEC program is recognized by all fifty states in the U.S., Canada, and the United Kingdom and DRE training in the use of the twelve-step
S1process is scientifically validated by both laboratory and field studies.
Testing for cannabis
U.S. states prohibit the operation of a motor vehicle while under the influence of drugs, including marijuana. For example, in Illinois it is illegal to operate a motor vehicle with a THC level of 5 nanograms or more per milliliter of whole blood or 10 nanograms or more per milliliter of other bodily substances.
Under that law, an individual can be arrested for driving under influence of cannabis at any THC level, including under the per se legal limits if an Officer believes the individual is impaired by cannabis.
It can be important to perform testing soon after a traffic stop, as THC plasma levels decline significantly after the passage of one or two hours. A number of companies are developing roadside THC breathalyzers that may be used by the police to help identify drivers impaired by the use of marijuana. Some nations use saliva swabs to test for THC levels at roadside, but questions remain about the reliability of saliva testing.
Other charges
Child endangerment
In the US state of Colorado, impaired drivers may be charged with child
endangerment if they are arrested for DUI with minor children in the vehicle.
Wet reckless
"Wet reckless" is a term used informally when a driver takes a plea bargain, agreeing to plead guilty to
reckless driving
In United States law, reckless driving is a major moving violation related to aggressive driving that generally consists of driving a vehicle with willful or wanton disregard for the safety of persons or property. It is usually a more serious o ...
in exchange for the elimination of the drunk driving charge. In California, a driver may not be charged or arrested for "wet reckless" driving, and the sole function of the charge is as a possible disposition following a plea bargain for a driver charged with DUI.
Penalties
In the case of a crash,
car insurance
Vehicle insurance (also known as car insurance, motor insurance, or auto insurance) is insurance for automobile, cars, trucks, motorcycles, and other road vehicles. Its primary use is to provide financial protection against physical damage or bo ...
may be automatically declared invalid for the intoxicated driver; the drunk driver would be fully responsible for damages. In the American system, a citation for driving under the influence also causes a major increase in car insurance premiums.
The German model serves to reduce the number of crashes by identifying unfit drivers and revoking their licenses until their fitness to drive has been established again. The
medical-psychological assessment works for a prognosis of the fitness for drive in future, has an interdisciplinary basic approach, and offers the chance of individual rehabilitation to the offender.
Worldwide
The laws relating to DUI vary significantly between countries, particularly the thresholds at which a person is charged with a crime. In many countries,
sobriety checkpoint
A random checkpoint is a military and police Military tactics, tactic. In a military context, checkpoints involve the setup of a hasty roadblock by mobile truck- or armored vehicle-mounted infantry to disrupt unauthorized or unwanted movement or m ...
s (roadblocks of police cars where drivers are checked), driver's license suspensions, fines, and prison sentences for DUI offenders are used as part of an effort to deter impaired driving. In addition, many countries have prevention campaigns that use
advertising
Advertising is the practice and techniques employed to bring attention to a Product (business), product or Service (economics), service. Advertising aims to present a product or service in terms of utility, advantages, and qualities of int ...
to make people aware of the danger of driving while impaired and the potential fines and criminal charges, discourage impaired driving, and encourage drivers to take taxis or public transport home after using alcohol or other drugs. In some jurisdictions, a
bar or restaurant that serves an impaired driver may face civil liability for injuries caused by that driver. In some countries, non-profit advocacy organizations, a well-known example being
Mothers Against Drunk Driving (MADD) run their own publicity campaigns against drunk or impaired driving.
US federal regulation
The
United States Department of Transportation
The United States Department of Transportation (USDOT or DOT) is one of the executive departments of the U.S. federal government. It is headed by the secretary of transportation, who reports directly to the president of the United States a ...
(USDOT) regulates many occupations and industries, and has a zero tolerance policy pertaining to the use of cannabis for any regulated employee whether he or she is on-duty or off-duty. Regardless of any State's DUI Statutes and DMV Administrative Penalties, a Commercial Driver's License "CDL" holder will have his or her CDL suspended for 1-year for a DUI arrest and will have his or her CDL revoked for life if they are subsequently arrested for driving impaired.
European Union
In 2025, during the negotiation of the new rules for the European driving license an EU-wide two years probationary period was proposed without alcohol, but member states may have to apply stricter rules for driving under the influence of alcohol or drugs.
See also
*
Alcoholism
Alcoholism is the continued drinking of alcohol despite it causing problems. Some definitions require evidence of dependence and withdrawal. Problematic use of alcohol has been mentioned in the earliest historical records. The World He ...
*
Alcohol-related crime
Alcohol-related crime refers to criminal activities that involve alcohol (drug), alcohol use as well as violations of regulations covering the sale or use of alcohol; in other words, activities violating the alcohol laws. Some crimes are uniquel ...
*
Breathalyzer
A breathalyzer or breathalyser (a portmanteau of ''breath'' and ''analyzer/analyser''), also called an alcohol meter, is a device for measuring breath alcohol (drug), alcohol content (BrAC). It is commonly utilized by law enforcement officers ...
*
Designated driver
The terms "designated driver" and "designated driving" (commonly known as DD) refer to the selection of a person who remains sober as the responsible driver of a vehicle whilst others have been allowed to drink alcoholic beverages.
Thus, as a pr ...
*
Driving laws
*
Drug–impaired driving
Drug-impaired driving, or drug driving, in the context of its legal definition, is the act of driving a motor vehicle while Driving under the influence, under the influence of an impairing substance. DUID, or Driving Under the Influence of Recrea ...
*
Drunk drivers
*
Drunk walking
*
DUI laws in California
*
DWI court
*
Fetal alcohol spectrum disorder
Fetal alcohol spectrum disorders (FASDs) are a group of conditions that can occur in a person who is exposed to alcohol during gestation. FASD affects 1 in 20 Americans, but is highly misdiagnosed and underdiagnosed.
The several forms of the ...
*
Mothers Against Drunk Driving (MADD)
*
Mobile phones and driving safety
Mobile phone use while driving is common but it is dangerous due to its potential for causing distracted driving and subsequent crashes. Due to the number of crashes that are related to voice call, conducting calls on a phone and texting while dr ...
*
National Motorists Association
*
Open-container law
*
Responsible drug use
Responsible drug use seeks to maximize the benefits and minimize the risks associated with psychoactive drug use. For illegal psychoactive drugs that are not diverted prescription controlled substances, some critics believe that illegal recreationa ...
*
Driver's license: point system
*
Zero tolerance
A zero-tolerance policy is one which imposes a punishment for every infraction of a stated rule.zero tolerance, n.' (under ''zero, n.''). The Oxford English Dictionary, 2nd Ed. 1989. Retrieved 10 November 2009. Italy, Japan, Singapore China, I ...
References
Further reading
*
Barron H. Lerner (2011). ''One for the Road: Drunk Driving Since 1900''. Baltimore, MD:
Johns Hopkins University Press
Johns Hopkins University Press (also referred to as JHU Press or JHUP) is the publishing division of Johns Hopkins University. It was founded in 1878 and is the oldest continuously running university press in the United States. The press publi ...
.
External links
Impaired drivingon
MedlinePlus
MedlinePlus is an online information service produced by the United States National Library of Medicine. The service provides curated consumer health information in English and Spanish with select content in additional languages.
The site brings ...
{{DEFAULTSORT:Driving Under The Influence
Alcohol law
Alcohol abuse
Crimes
Traffic law
Traffic psychology
Social responsibility
Car crime