Explaining Field Sobriety Tests and Chemical Tests in a DUI Case

Posted on July 24, 2014

One-legged Stance Test

Clients of a Redwood City DUI attorney often ask about the field sobriety tests and how reliable they are in comparison to chemical tests.

Reliability of Field Sobriety Tests in Comparison to Chemical Tests

When a driver is tested to determine whether or not there is impairment, the most accurate method is believed to be a trustworthy test for blood alcohol content. These are used to come to an objective and accurate blood alcohol concentration, or BAC. The assessment as to whether the driver has surpassed the legal limit for operating a motor vehicle will be based on this test.

Field sobriety tests are considered less trustworthy. The judgments are subjective and often hinge on the opinion of the person overseeing the test. Regardless of their weaknesses, they are still used to:

  1. Give the law enforcement officer a justifiable reason to have made the traffic stop or arrested the driver;
  2. Provided the possibility of some form of impairment near the time when the person was driving; and
  3. Show a link between the alcohol use and the way in which the driver was operating the vehicle.
Various Kinds of Field Sobriety Tests

There are numerous field sobriety tests that are used including:

  1. Touching the finger to the nose;
  2. Having the driver recite the alphabet or writing it on a signed and dated piece of paper;
  3. Beginning at number 100 and counting down;
  4. The Horizontal Gaze Nystagmus Test, or HGN;
  5. The walk and turn test;
  6. The Romberg balance test or the Romberg balance test while touching the finger to the nose;
  7. Finger counting test;
  8. The officer will ask the driver questions that are designed to distract or interrupt while they’re being answered; and
  9. One leg stand test.
Contact an Experienced Redwood City DUI Lawyer

If you have been arrested for DUI or have questions about the DUI arrest procedure with field sobriety tests and chemical tests, contact Silveira Law at (415) 795-3890.