Blood Alcohol Concentration or Breath Alcohol Concentration
The amount of alcohol contained within a person’s breath that is stated to be equivalent to the amount in a person’s blood. The Legal limit in Texas is .08.
FST are field exercises that police use to determine whether a suspect is intoxicated. These test include the Horizonal Gaze Nystagamus (HGN), Walk and Turn, and the one leg stand. The National Highway and Safety Administration has adopted these tests as reliable scientific evidence of intoxication, however the reliability of these test is disputed by many experts in the field. These test are controversial for several reasons one being the obvious: most sober people can not perform well on these test. Many scientist have critiqued these test is stating they are designed for failure. Dr. Marcilline Burns, a PH. D in Psychology the person behind the development of these tests, has stated that these test would result in the zero tolerance meaning that most sober people would not pass. Furthermore these tests have not been peer reviewed within the scientific community.
This is an administrative license revocation hearing. The Texas Department of Public Safety will try to suspend the drivers license of a person who either blows over a .08 on the breath-test or refuses to blow.
This is the breath test machine used by police agencies in Texas. This machine is made by a company called CMI. CMI does not warrant this machine, for a particular purpose. This Machine also has credibility problems as it has a 20% margin of error, and it is susceptible to numerous interferents that can give false positive results. The “Texas Intoxilyzer” (the machines used in Texas) have not been updated with the latest modifications and filters recommended by CMI.
This is the “eye test” within the battery of field sobriety tests. The theory is that alcohol intoxication causes nystagumus (an involuntary jerking of the eye). The problem with this test is that there are over 48 different types of nystagumus other than alcohol induced nystagmus. Many officers are predisposed to consider only alcohol induced nystagumus when reasonable science would point to one of the other 48 different types of nystagmus as responsible for causing involuntary eye movement.
This is another field sobriety test within the battery of test. While officers try to explain this test as being simple it is graded in a way to cause people to fail. This test is premised on performing over 100 different movements perfectly requiring only 2 of those movements to be off as clues of intoxication. That means a person who performs this 98% accurate would fail.
This is another field sobriety test within the battery of test. Again critics state that this test was designed to fail. Most people who take this test will have problems with it based upon numerous items that even the police will agree invalidates this test.
The Nation Highway Transportation and Safety Administration publishes a manual entitled outlining the administration and application of DWI investigation and field sobriety testing. Police agencies rely on this manual to testify about the FSTs.