Most drunk driving cases start out with a contact between the driver of a motor vehicle and a police officer. While the police have the right to approach and speak with any citizen, they do not have the right to detain and investigate a citizen unless they have "probable cause".

Probable cause is the legal reason an officer needs to detain and investigate. If the dui attorney can show to the judge the officer did not have probable cause, the case can be dismissed.

Most detentions begin with the officer pulling over a driver who has committed a vehicle code infraction. The common reasons alleged by the police are based on poor driving - speeding, weaving within or outside the lane, running of a stop sign or red light. However, faulty equipment (head light, tail light, muffler) or expired registration will provide the necessary reason to pull a driver over. A driver involved in an accident or in a car blocking the roadway may also give the officer the right to detain and investigate.

It is therefore important to discuss with the dui attorney the manner of driving. If the driver was acting legally, or if the officer did not see the driver actually operate the vehicle, the case may be dismissed. Not only does the officer need probable cause to detain and investigate, there must also be a legal reason to arrest. The officer will make his decision to arrest based on two or three factors: his observations, the field sobriety test, and in some jurisdictions, a breath test conducted in the field.

For this and more information on criminal law and drunk driving go to: