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Tolleson Field Sobriety Test Lawyer

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Tolleson Field Sobriety Test Attorney

Field sobriety tests are a common occurrence for Tolleson drivers who are suspected of driving while intoxicated. These tests are supposed to gauge whether somebody’s response implies they are likely impaired by a substance – but are they as reliable as many people think?

One of our DUI defense attorneys, Ryan McPhie, explains the flaws in these tests and why you should call Grand Canyon Law Group immediately if an officer used these tests to charge you with drunk driving.


Field sobriety tests are a series of tests which a Tolleson police officer conducts to determine whether they think a driver is impaired by drugs or alcohol. In our experience, though, those tests are just used to produce reasons against the suspect to support the officer’s arrest decision.

There is the horizontal gaze nystagmus (HGN) test that analyzes the movement of the driver’s eyes. It is the first one the officers usually perform, which involves them holding a pen or a small flashlight back and forth in front of a person’s face, while looking at their eyes. The other tests, which are considered validated tests, are the walk-and-turn, where the suspect walks on a line, turns around, and walks back; and a test where the suspect must stand on one leg without falling.

There are other tests which are not validated but are also used often. These include asking the driver to reach their arm out and bring it back to touch their nose, and the Romberg modified test where they tilt their head back and count backwards.


It is extremely important that these tests, especially the ones which are seen as validated, are administered correctly. These tests are only seen as validated if performed in the correct way. The officer must provide correct instructions, demonstrate the test correctly, and the conditions must be appropriate for somebody to be doing one of these tests (it would not be prudent to conduct a test in a heavy wind storm or thunderstorm, for example). If any of those aspects are missing, an aggressive defense attorney can attack the prosecutor’s case by arguing the test were unreliable or invalid.


When it comes to how much weight is put on these field sobriety tests at a trial in Tolleson, it is different for every case. Some juries find field sobriety tests to be very convincing and powerful evidence. We do our best to explain that these tests are not a good indicator on whether or not somebody was intoxicated or impaired. It also depends on how good or bad the person’s performance was on those tests.

Sometimes people believe they did extremely poorly on the test because of all the checkmarks the officer gave them. That is not always a good indicator of how well somebody performed, because these officers are not objective observers. They are subjective and often they are not grading it fairly. We use our history as prosecutors to explain these concepts when explaining a case to a jury.


In nearly all circumstances, drivers pulled over on suspicion of drunk driving should refuse to perform physical sobriety tests, including the eye test. Non-intoxicated drivers often fail them, especially since it is up to the officer’s discretion on whether you succeeded or not. You must still comply with a breathalyzer request, if they insist.

Whether you complied with these tests and got arrested, or you refused, you need to contact our criminal defense team as soon as possible. Field sobriety tests in Tolleson are unreliable but can still be a factor in court. Contact us and speak with a legal professional from Grand Canyon Law Group.

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