As several prior posts on this Wisconsin DUI defense law blog have discussed, a breathalyzer test measures the concentration of alcohol that a person has in his system at the time he blows his breath into the testing device. A breathalyzer reading at or in excess of .08 generally indicates an impermissible level of alcohol in a driver's body. However, a reading below .08 does not guarantee that a driver will avoid arrest on DUI or another drunk driving-related charge.
When evaluating an individual who is suspected of committing DUI or another drunk driving offense, an officer may consider other evidence of intoxication to determine if an arrest should be made. For example, a person's driving conduct - swerving, hitting parked vehicles and other apparent out-of-control actions - may be used as evidence of intoxication for supporting a drunk driving arrest. During a police stop, how a driver conducts himself can also be used as evidence in a case against him. Slurred speech, the inability to focus and other physical attributes of a driver may be considered before an arrest is made.
However, alcohol is not the only factor that can cause a person's appearance or driving conduct to be affected. For this reason it is important for drivers to know their rights with regard to drunk driving-related arrests. Drivers may present their own evidence during their drunk driving trials that explains the evidence the police officer used to justify his arrest of the individual.
Breathalyzer tests are often considered a standard in determining driver intoxication. However, as discussed in this blog post, other forms of evidence may also be collected against drivers to demonstrate sufficient proof of driving in an intoxicated state. People who are preparing to defend themselves against drunk driving charges can use their own evidence to support their cases when the go to trial.