As previously discussed, officers are trained in three different Phases of Driving While Intoxicated detection. Phase 1 involves the officer’s observations of the vehicle in motion, Phase 2 involves the officer’s personal contact with the driver and Phase 3, which I will discuss here, involves Pre-Arrest Screening.

During Phase 3, the officer will determine whether the driver has consumed alcohol and whether such consumption has impaired the driver to the extent that he should be arrested. The main focus during Phase 3 is on the driver’s performance on the Standardized Field Sobriety Tests (SFSTs). During this Phase the officer might also ask the driver to blow into a Portable Breath Test (PBT) to determine the presence of alcohol but the PBT should only be used to support the SFST; it should not be used in place of SFSTs. In New York, the results of a PBT are not admissible at trial (but they are admissible at pre-trial hearings).

The SFSTs not only determine impairment but also whether the driver can perform divided attention tasks. The only three SFSTs validated by the National Highway Traffic Safety Administration (NHTSA) are the (1) Walk-and-Turn; (2) One-Leg-Stand; and (3) Horizontal Gaze Nystagmus. These will all be discussed separately in future blogs.

After the driver has performed the SFSTs, the officer will make a determination with regard to intoxication based upon the totality of the evidence developed during all three Phases of DWI detection.

If you have been arrested for Driving While Intoxicated (DWI) in New York, feel free to contact us at toll-free at 1-888-DWI-COUNSEL or visit us on the web at Those charged with DWI need attorneys who know not the law, but the science and procedures relevant to DWI. Managing partner, Peter Tilem, is certified in Driving Under the Influence Detection by Blackwater Worldwide having successfully completed the same 8 hour course many members of law enforcement have taken.

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