How Do Police Officers Administer Field Sobriety Tests?

 Posted on July 15,2021 in Criminal Law

texas defense lawyerDWI arrests are considered high priority by state and local jurisdictions in not just Texas, but all across the country. And because of that, the federal government tasked the National Highway Traffic Safety Administration with creating standards and instructions for training officers on how to investigate DWI cases

According to NHTSA guidelines, a DWI investigation involves three steps: vehicle in motion, personal contact, and pre-arrest screening, i.e., field sobriety tests.  The vehicle in motion stage is like making a reservation at a restaurant, the personal contact stage is like ordering from the menu, and the pre-arrest screening is like dinner rolls at the table. The most substantive part of the interaction is usually the pre-arrest screening. It begs, why are field sobriety tests so important in a DWI case?

Field Sobriety Tests

Contrary to what many believe, you cannot fail a field sobriety test. Instead, police rely on them to uncover indicators of impairment. The three primary tests include the Nystagmus Test, the Walk and Turn, and the One Leg Stand. In the first one, you either show nystagmus or you do not, and then the other two require you to follow specific instructions and demonstrate balance and coordination. 

During the Nystagmus Test, the officer will have you follow a stimulant -- usually, either their finger or a pen -- and then they will monitor your eyes. Nystagmus is defined as the involuntary movement of the eye, so the officer is looking for your eyes to jerk instead of move smoothly. They will do three rounds and have the chance to identify six clues. 

The Walk and Turn is a two-part test. In the first part, the officer will tell you to get into the starting position with your right foot in front of the left and hands at your side. Once you are in that position, they will explain and demonstrate how to complete the test. Here, they are looking for eight clues. In this case, a clue is starting too early, stopping, stepping off the line, swinging your arms, taking too big a step, turning incorrectly, or taking too many steps. 

The last test, the One Leg Stand, requires you to stand on one leg as the other is raised approximately six inches off the ground. You are to keep your hands at your sides, stare at your foot, and count starting from 1,000. The officer will look to see if you lose balance in any way. They have the chance to identify four clues. 

Contact a San Antonio, TX DWI Defense Attorney

If you have been charged with DWI, contact an experienced San Antonio criminal defense attorney for help. In his more than a decade of practicing law, attorney Sam H. Lock has received numerous accolades and high praise from his clients and colleagues. Mr. Lock and the rest of our skilled team can help you dispute the validity of field sobriety tests and other evidence against you. We can help you develop a robust defense against DWI charges. Contact the Law Offices of Sam H. Lock for a Just call 1-888-SAM-LOCK or 210-226-0965.



Share this post:




Bexar County

In the historic King William District

1011 S. Alamo,
San Antonio, Texas 78210