Challenging DUI Evidence

Contesting Field Sobriety and Chemical Test Findings

A crucial component of defending someone facing drunk driving charges is challenging the evidence that warranted the arrest – field sobriety tests – and the evidence that warranted the formal charges – chemical tests. At Gold & Witham, we have more than 40 years of experience doing just that. We also work with some of the top criminalists and DUI test experts in the region to defend our clients facing drunk driving charges.

Standardized Field Sobriety Tests or "SFSTs"

All law enforcement officers are trained to administer the same SFSTs and are held to the same standards. The SFST standards are regulated by the National Highway Traffic Safety Administration (NHTSA). There are three field sobriety tests, and law enforcement officers can use any one or combination of the three at a DUI traffic stop.

• Horizontal Gaze Nystagmus – The HGN test requires the driver to follow the tip of an object (usually a pen or flashlight) laterally from right to left and back. When intoxicated, nystagmus (eye movement or twitching) is exaggerated.
• Walk and Turn – This is one of the "divided attention" tests. Like the one-leg stand, the driver must focus on two things at once, which is difficult when intoxicated. With the walk and turn, the driver takes nine steps forward in a straight line, turn around, and come back the same way.
• One-Leg Stand – The law enforcement officer will ask the driver to stand on one leg with the other six inches off the ground for about 30 seconds. Intoxicated drivers will have a difficult time keeping their balance.

The problem with field sobriety testing is that it relies on the subjective perception of the officer, rather than objective scientific evidence. There are also a number of factors other than intoxication (such as medical conditions or exhaustion) that can mimic intoxication and result in failed SFSTs.

Chemical Testing

It is unlawful to administer a chemical test unless the driver has been lawfully arrested. Unlike field sobriety tests, refusing a chemical test can warrant automatic license suspension. There are three types of chemical testing for drunk or drugged driving:

• Breath (breathalyzer) tests
• Blood tests
• Urine tests

The margin of error for breath tests is actually quite high, so the results of breath tests can be contested by calling into question the accuracy of the testing device or the method of testing. In some cases, breath tests can be improperly calibrated or monitored, which can increase the margin of error. Blood and urine tests are more accurate than breath tests, but not flawless.

Contacting Our South Bay DUI Lawyers

If you were arrested for drunk driving after allegedly failing the field sobriety tests and/or charged after testing above the legal limit in a chemical test, contact the DUI attorneys at Gold & Witham. DUI defense is what we do – let our proven methods be your peace of mind.

Call (310) 870-1094 today for a free evaluation of your case!