Understanding The Tests Used To Determine If You Were Driving Drunk

If the driver has been stopped for suspicion of driving under the influence they will usually be ordered out of the motor vehicle to perform field sobriety tests. While standing on the side of the road, a police officer guides the driver through a group of balance, coordination, and mental skill tests. Below are some typical tests used by practically all law enforcement agencies.

Challenges To Common Chemical DUI Tests

Once the police officer establishes there is probable cause to determine the driver is under the influence, the police officer will place the driver under arrest for driving under the influence and have him or her transported to jail for a chemical test. Many jurisdictions offer the driver the choice of a blood, breath or urine test.

A skilled Tennessee DUI defense attorney should be well-versed in each of these tests and will investigate the following factors in order to challenge the case in court:

The Breath Test

  • When was the breath machine last calibrated?
  • Has the machine been serviced just before or after the test?
  • Has the equipment and the operator been certified by the state?
  • Exactly what calculations does the device use in order to convert air flow alcohol to blood alcohol?
  • Is the device susceptible to outside interference coming from nearby electronic equipment?
  • Did the individual burp or belch just before taking the test?
  • Did the individual use mouthwash or breath spray that may have contained alcohol before taking the test?

The Blood Test

  • Was the blood drawn within the time specified by law?
  • Was the blood drawn by a person who is certified to do so?
  • Was the proper amount and type of preservative used in the vial used to store the blood?
  • Was the blood properly stored after the test?
  • Is there a sample readily available for the defense to test independently?
  • Were the officials, procedures and equipment used in the test all certified by the proper authorities?

The Urine Test

  • Did the individual completely empty his or her bladder before he or she provided the urine sample?
  • Did the individual being tested wait the required time before he or she provided the sample?
  • Was the sample correctly stored after testing?
  • Is there a sample readily available for the defense to test independently?
  • Were the officials, procedures and equipment all certified by the proper authorities?

These kinds of questions will go a long way in putting a ding in the prosecutor's case. If you were arrested after taking a chemical test, you still have options. Call 888-DUI-CALL (866-893-8413) or 865-329-6982 locally in Knoxville to speak with our experienced DUI defense team today!