How accurate and reliable are the police methods used to determine alcohol concentration?
If all of the tests are performed in a controlled environment, and are administered by a highly trained officer in the exact standardized manner, these tests can be a good indicator of intoxication. However, in reality these tests are rarely performed in this manner. In a 1998 study, the National Highway Traffic Safety Administration retooled the field sobriety tests for the new 0.08 BAC levels, and they found the following results: • Horizontal Gaze Nystagmus can correctly identify a subject who has a BAC of 0.08 or higher in 88% of the time • Walk and Turn is correct 79% of the time • One Leg Stand is correct 83% of the time That means that, even under laboratory conditions, these tests are inaccurate 21%-12% of the time. Under realistic roadside conditions, these percentages drop dramatically. The state of Texas allows law enforcement agencies to test an individual’s BAC by means of either a breath, blood or urine test. While these tests might sound accurate to the uninformed person
