Law enforcement employs an arsenal of equipment and tests to determine how intoxicated a driver may be. A common method of testing that has been used since the advent of drunk driving laws are FST (Field Sobriety Test). Some common FSTs are HGN (Horizontal Gaze Nystagmus), one-leg-stand, walk-and-turn, finger-to-nose, and counting backwards. Each test has its own advantages and disadvantages. However, they all share the same disadvantage of relying on basic physical abilities that not all people possess.


As it sounds, the suspect will stand on one leg. If there is any swaying or imbalance the suspect could be charged with DUI. The test may be inaccurate if the driver is overweight, affected by prescription drugs, has poor night vision or is wearing high heel shoes.

HGN (Horizontal Gaze Nystagmus)

The HGN test is perhaps the most widely accepted and scientifically approved. The police officer will have the subject follow an object (such as a pen) while the officer checks for signs of intoxication, lack of smooth pursuit, deviation, etc. Prescription drugs and various medical conditions can also influence eye nystagmus.


The suspect will take 10 steps (heel to toe), then turn and repeat the 10 steps back. The officer will be checking to see if the driver is following directions properly and able to perform the physical actions without any tripping or swaying. Again, the test is making the assumption that the suspect does not have any physical condition that could impact the results.

Finger-to-nose, counting backwards and reciting the alphabet

To perform the finger-to-nose test, the driver will extend each arm and touch the tip of their nose with their index finger. Missing the tip of the nose may result in further testing or DUI charges. Counting backwards or reciting the alphabet could be complicated by the pressure of the situation, potentially nullifying any negative results.

How can the results be dismissed?

Aside from the physical assumptions in FSTs, it is important that the suspect understands what the officer is requesting. If needed, the officer should demonstrate the task he is demanding you complete. This is particularly important if there are any language barriers.

A DUI charge does not equal a DUI conviction. Contact Scott Tolbert to discuss your DUI charge. We handle cases like yours every day. In many instances DUI charges can be completely dropped! We’re ready for your case.

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