San Antonio DWI Field Sobriety Tests

There are basic Standard Field Sobriety Tests (SFSTs) prescribed by the National Highway Traffic Safety Administration (NHTSA): the Horizontal Gaze Nystagmus (HGN), the Walk and Turn (WAT), and the One-Leg Stand (OLS). A San Antonio DWI lawyer will have a strong grasp of how Texas law enforcement is supposed to administer the tests and the specific vulnerable areas in each test that are open for challenge.

There are some basic general concepts regarding SFSTs. The SFSTs are constructed in such a manner so that the participant WILL fail them. Within a short time after the driver has exited the vehicle, law enforcement has already decided that the driver is intoxicated and only seeks SFSTs to convince a jury on video. The SFSTs must be administered by qualified law enforcement. A San Antonio criminal defense lawyer will obtain proof of certification from the Texas Commission of Law Enforcement Officer Standards and Education (TCLEOSE) . Moreover, active certification only lasts 2 years before the officer requires recertification. Therefore, there is the very real possibility that an officer is not properly certified to administer the SFSTs.


In our last blog entry, we discussed how San Antonio law enforcement will use distracting questions that are not DWI standard tests in order to see if the driver can perform different tasks at once. This “unusual” questions technique continues while the officer gets ready to administer the SFSTs. The officer will ask the driver to move to a different position before each SFST to demonstrate on video if the driver sways and stumbles while moving to a different area of the roadway.

Texas law enforcement will not make notations on the report that an allegedly intoxicated driver moved steadily without stumbling to different sections of the roadway to perform SFSTs – it is up to a Texas DWI defense lawyer to point out to the jury and on officer questioning that the driver was exhibiting signs of non-intoxication in his movements.

Whether the driver is intoxicated or not, the SFSTs have characteristics that make failure inevitable. The Bexar County District Attorney and SAPD will point out all the negative points concerning the driver’s participation on the SFSTs – a strong Bexar County DWI lawyer must educate a jury about all the clues of non-intoxication.

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