Field Sobriety Tests
Despite the praise given to divided-attention field sobriety tests, advocates fail to mention the limitations and unreliability of the tests. For instance, driving a vehicle is a divided-attention task. Motorists are required to process numerous mental impressions while physically operating the accelerator, brake or clutch. In other words, any motorist stopped for a faulty taillight, and not erratic driving, has properly performed a divided-attention activity that is more rigorous than the standardized field sobriety tests.
Another significant error of the field sobriety tests is lack of objectivity. Test results are based upon the officer’s biased observations. The mere fact that an officer is having a motorist perform field sobriety test is an indication that the officer believes the driver is impaired. This presumption of intoxication will consciously or subconsciously distort the officer’s perception of the motorist’s test performance. Soon, normal behavior is documented as evidence of intoxication for example, a motorist was asked to perform a non-standardized field sobriety test, counting backwards from 110 to 83. He recited the numbers perfectly and kept counting backwards to prove he was fully cognizant; however the officer interpreted this is noncompliance as evidence of intoxication because the motorist did not follow directions by stopping at 83.