Thus, for all practical purposes, this is the same as the simple dimensionless BAC measured as a percent.
A BAC or Br AC measurement in excess of the specific threshold level, such as 0.08%, defines the criminal offense with no need to prove impairment.
In some jurisdictions, there is an aggravated category of the offense at a higher BAC level, such as 0.12%, 0.15% or 0.25%.
In most countries, sobriety checkpoints (roadblocks of police cars where drivers are checked), driver's licence suspensions, fines and prison sentences for DUI offenders are used as a deterrent.
Anyone who is convicted of driving while under the influence of alcohol or other drugs can be heavily fined or given a prison sentence.
In relation to motor vehicles, the Road Traffic Act 1988 creates a narrower offense of driving (or being in charge of) a vehicle while having breath, blood or urine alcohol levels above the prescribed limits (colloquially called "being over the limit"); and a broader offense of "driving while unfit through drink or drugs," which can apply even with levels below the limits.
A separate offense in the 1988 Act applies to bicycles.
In some jurisdictions, the bar that served an impaired driver may face civil liability.
In some countries, non-profit advocacy organizations, a well-known example being Mothers Against Drunk Driving (MADD) run their own publicity campaigns against drunk driving.
Other commonly used terms to describe these offenses include drinking and driving, drunk driving, drunken driving, impaired driving, operating under the influence, or "over the prescribed limit".
In the United Kingdom, the offense is often known as "drunk in charge of a motor vehicle" or "drunk in charge" due to the wording of the Licensing Act 1872.
In many jurisdictions, police officers can conduct field tests of suspects to look for signs of intoxication.