LAwyer description
Driving under the influence of
alcohol, drunk driving, or drink-driving, is the act of
operating a motor vehicle (and sometimes a bicycle or
similar human-powered vehicle) after having consumed
alcohol (ethanol) or other drugs, to the degree that
mental and motor skills are impaired. In addition to
driving under the influence of alcohol and driving under
the influence of other drugs, a third "DUI" offense
consists of driving under the combined influence of
alcohol and other drugs. The drugs causing or
contributing to the impairment need not be illegal, but
can consist of lawfully prescribed or over-the-counter
medication. Anti-drunk-driving advertising campaigns
have aimed to raise awareness of the legal situation and
the dangers of driving while intoxicated. Drunk-driving
is responsible for a large number of deaths, injuries,
damage and accidents every year.
The specific criminal offense may be called, depending
on the jurisdiction, driving while intoxicated (DWI),
driving while impaired (also DWI), operating while
intoxicated (OWI), operating a motor vehicle while
intoxicated (OMVI), driving under the influence [of
alcohol or other drugs] (DUI), driving under the
combined influence of alcohol and/or other drugs or
drunk in charge [of a vehicle]. Such laws may also apply
to boating, or piloting aircraft.
Historically, guilt was established by subjective tests
of the driver's impairment, such as difficulty reciting
the alphabet or walking a straight line, together with
the arresting officer's subjective opinion. Starting
with the introduction in Norway in 1936 of the world’s
first per se law which made it an offense to drive with
more than a specified amount of alcohol in the body,
objective chemical tests have gradually supplemented the
earlier purely judgmental ones.
Today's statutes commonly provide for two separate and
distinct criminal offenses. The first is the traditional
"drunk driving" offense, consisting of driving under the
influence of alcohol and/or drugs. Evidence to support
this crime generally comes from the officer's
observations (erratic driving, slurred speech, unsteady
gait, etc.), performance on field sobriety tests, and a
legal (and generally rebuttable) presumption of
intoxication from a blood alcohol test result over the
legal limit. The second offense is the more recent
so-called "per se" offense: rather than focusing on
impairment the crime consists entirely of having a given
blood alcohol content (BAC) at the time of driving,
regardless of the individual's tolerance to alcohol.
Both offenses may be charged, and the defendant may be
convicted of both; if a blood alcohol test result was
not obtained, only the traditional "DUI" offense will be
charged.
BAC is most conveniently measured as a simple percent of
alcohol in the blood by weight. It does not depend on
any units of measurement. In Europe it is usually
expressed as milligrams of alcohol per 100 millilitres
of blood. However, 100 milliliters of blood weighs
essentially the same as 100 milliliters of water, which
weighs precisely 100 grams. Thus, for all practical
purposes, this is the same as the simple dimensionless
BAC measured as a percent. Since 2002 it has been
illegal in all 50 US states to drive with a BAC that is
0.08% or higher.
Driving while consuming alcohol is generally illegal,
though driving after drinking remains legal. In some
jurisdictions it is also illegal for an open container
of an alcoholic beverage to be in the passenger
compartment of a motor vehicle or in some specific area
of that compartment.
New Zealand has a limit of 0.08% for drivers over 20
years, 0.03% for those under. |
