In the United States it is illegal to drive with a BAC (blood alcohol content) level of 0.08% or higher. For a minor the legal limit is lower at 0.01%. BAC level will be used as evidence to prove that a person was driving while intoxicated.
If you are pulled over for a DUI, the police officer will often ask you to take a Breathalyzer test. This test will require you to blow into a device that will analyze the amount of alcohol in the air exhaled from your lungs.
It is assumed that the alcohol in the air expelled out from your lungs is the same the alcohol level in your blood. However, many experts agree that the results of a Breathalyzer test can be inaccurate.
Under certain circumstance you may be asked to take a blood or urine test in order determine your BAC.
When pulled over, you can refuse to take a Breathalyzer test or any other field sobriety test requested by the police officer. Any test you refuse to take will be less evidence against you in court, but may lead to your arrest and suspension of your license.
Penalties for a DUI conviction for a first conviction:
Penalties for subsequent offenses become increasingly harsher. If there is an accident and injury is involved in the DUI, it can be charged as either a misdemeanor or a felony depending on the circumstance of the incident.