If you were arrested for DWI or DUI in Houston or anywhere in Texas, an experienced criminal defense attorney should work to challenge each phase of the police’s investigation. In DWI and DUI investigations, police officers follow guidelines set out by the National Highway Transportation  Safety Administration (“NHTSA”). These guidelines cover DWI detection and the administration of Standardized Field Sobriety Tests (“SFSTs”).

An experienced DWI or DUI defense lawyer should be familiar with these guidelines. In general, the NHTSA manual breaks a DUI or DWI investigation up into three main phases known as vehicle in motion, personal contact, and pre-arrest screening.

In the vehicle in motion phase, the police officer will observe an individual’s driving behavior, and look for clues claimed by NHTSA to be consistent with impaired driving. In DWI or DUI cases, these driving behaviors include swerving, driving erratically, driving on the wrong side of the road or driving with the lights off.

In DWI or DUI investigations, the personal contact phase of the investigation takes place after the police officer has already made the decision to stop an individual and initiate an investigation. This phase includes face-to-face contact with the driver. During this phase, the police officer will attempt to gauge whether the driver is sober based on his appearance, behavior, smell, balance, coordination, his manner of speaking, and any statements he may make. DWI and DUI criminal defense lawyers know that this phase of the investigation can lead to unreliable conclusions. After all, the police officers has not previously met the suspect, so it is questionable whether he can determine what the suspect is “normally” like.

In any event, in DUI or DWI investigations, if the police officer believes that the suspect is intoxicated after phase one and phase two are completed, he may then move into phase three, where the police officer will administer standardized field sobriety tests. The tests outlined by NHTSA are standardized, meaning that they are conducted the same in all DWI or DUI investigations, in Houston and anywhere. The three standardized tests include the horizontal gaze nystagmus test, the one-leg stand, and the walk and turn. DWI and DUI criminal defense attorney also know that problems in the administration of the test are common. A surprising number of officers do not follow the guidelines set out by NHTSA.

DWI and DUI law can be specialized and it is important to hire an experienced criminal defense attorney if you are charged with a DWI or DUI in Houston, or anywhere in Texas. An experienced criminal defense lawyer will be able to aggressively challenge each phase of the police’s investigation, with the goal of achieving the best possible result in your case.