When you are pulled over for a traffic stop in which an officer suspects any kind of alcohol ingestion, the officer will attempt to engage you in extended conversation. This conversation is not friendly banter, nor is he interested in hearing your answers.  The only thing the officer is doing is attempting to measure your impairment and find reasonable cause to detain you further or do more testing.

Be polite, provide your identification and vehicle registration, and answer necessary questions shortly and succinctly.  Do not try to explain your way out of the stop, do not offer additional information, and do not attempt to argue with the officer.  Never volunteer where you were, what you were doing, or how much you had to drink.
Even more importantly, do not curse or argue with the officer.  Realize that, while you are stopped, the officer will be looking for any clues that you are too impaired to drive.  Your behavior can be a clue and may be accepted as reasonable cause to conduct additional testing or to arrest you.  Be polite to the officer, remain as calm as possible, and remember that whatever you do or say may find its way into a courtroom as very damaging evidence if you are arrested or charged with DWI.

To read more, stay tuned for Part 2: Field Sobriety Tests

This post contains excerpts from The DWI Book, the definitive guide to protecting your rights in the face of New Hampshire's tough DWI/DUI laws.