Below is an article written by a UK car rental company for customers travelling to the United States. Aside from calling it 'drunk driving' instead of 'drink driving', there are some interesting differences in how drunk driving is handled here in America. Notice that in Europe, a BAC of .08 is the highest legal limit for driving, though some places have a limit as low as .02! The article also mentions field sobriety tests as something the European traveler may not be familiar with and notes that we suspend drivers licenses immediately upon arrest.
In the UK and Europe, any driver may be asked to provide a sample of breath if a police officer considers them be under the influence of alcohol and behave in a manner suggesting alcohol consumption, fail to respond to questioning or are involved in an accident. The "breath test" involves the suspected drink driver making a sustained breath into the mouthpiece of a hand-held breathalyser, which measures Breath Alcohol Content. In the UK, the legal driving limit is 350µg of alcohol per litre of breath, though limits are lower in other European countries, being 250µg per litre in Spain and 220 µg per litre in Finland and Holland.
Registering a breath sample with an alcohol level exceeding the legal driving limit will result in the driver being arrested and take to the nearest police station, where 2 further readings are taken using a more sophisticated, accurate machine. If the lower of these 2 readings is above the legal limit, the drink driver will be charged and usually bailed to appear at a magistrates` court. If a reading is marginally above the legal limit, the suspect will be given the option of providing a blood sample, which will be sent away to a laboratory for testing.
Blood alcohol concentration (BAC) is the concentration of alcohol in a person`s blood and is the measure generally used in drink driving regulations. Worldwide, several different units are used to define the mass of alcohol per volume / mass of blood. For this reason, BAC is often expressed as a percentage in terms of volume of alcohol per volume of blood, e.g. 0.08%. As with legal breath alcohol limits, legal BAC limits vary across Europe, from 0.02% to 0.08%.
The legal BAC limit for driving in the USA is 0.08%. Police procedures for dealing with suspected drink drivers are generally similar to those used in Europe, although there are some important differences. The most controversial of these is the use of "field sobriety tests," which theoretically test a suspect`s ability to perform the mental / physical multitasking required in driving. Such tests include following an object with the eyes, walking heel-to-toe in a straight line, standing on one leg, placing a finger of the nose with eyes closed and reciting the alphabet backwards. Research has shown that some of these tasks cannot be achieved by completely sober subjects, especially those with non-obvious disabilities. Despite the fact that they produce many "false positive" results and are greatly subjective to the opinion of the arresting officer, such tests are still sanctioned by the National Highway Traffic Safety Administration. Fortunately, they are gradually giving way!
to the use of "preliminary breath testers," similar to the breathalysers used in the UK. The procedures following a positive test are virtually identical to those in Europe, although a driver`s licence is revoked PRIOR to conviction.
The best advice regarding US drink driving regulations for European travellers is for each of the party to take a turn at being the "designated driver" and refraining from any alcohol intake. This allows visitors to take advantage of cheap car hire in Washington with no fear of falling foul of drink driving laws.
As you can see, BAC laws similar to ours are in effect across much of Europe. If you travel and plan to drive in any another country, make sure you are aware of their drunk driving or drink driving laws.