Tests are conducted at Prince Georges County traffic stops to help police determine whether a driver is intoxicated. Criminal defense attorneys ask clients who've been arrested for drunk driving how and under what circumstances the tests were administered. An improperly conducted field sobriety test or flawed breath test can benefit a defendant.
Field sobriety tests are numerous but three tests are supposed to be the most accurate, according to the National Highway Traffic Safety Administration. Many drivers are familiar with these tests by sight or experience but possibly not by name -- the One-Leg Stand, the Walk-and-Turn and the Horizontal Gaze Nystagmus test. A failure to perform these tests to the satisfaction of an officer can create probable cause leading to a DUI arrest.
Each test challenges a driver's mental and physical capabilities. Tests involve asking a driver to count while standing on one foot, follow directions while walking a straight line or track the movement of an object with his or her eyes. Officers are specially trained to look for impairment indicators, like a loss of balance or a failure to adhere to instructions.
The NHTSA claims each test help police spot drivers whose blood alcohol levels are at least 0.08 percent, the legal limit. Individually, the tests have been estimated to be between 79 and 88 percent accurate and, collectively, up to 94 percent accurate depending upon the research source.
It is worth noting independent researchers saw an increase in overall accuracy after officers had been acclimated to administering the tests over several years. The best results occurred when the three tests were used in combination. No tests or combination of tests has guaranteed 100 percent accuracy.
A driver may fail a field sobriety test for reasons other than intoxication like limited physical or mental capacity. Consequently, some sober Maryland drivers are arrested. A criminal defense attorney can help find evidence to challenge test results and unfair DUI charges.
Source: National Highway Traffic Safety Administration, "Standardized Field Sobriety Testing," accessed Aug. 28, 2015