Police officers investigating a driver for DUI / DWI in California typically administer a field sobriety test before taking the driver into custody. These “tests”, which are usually conducted next to a busy street or freeway, aren’t really tests at all, because they’re designed for failure. Their true purpose is to create probable cause to make a drunk driving arrest and to gather evidence for a court case. A driver who took a field sobriety test before being arrested for drinking and driving should consult with a California criminal defense attorney who specializes in successfully defending DUI / DWI cases.
Three field sobriety tests are recognized by the National Highway Transportation Safety Administration (NHSTA) – the horizontal gaze nystagmus test, the walk and turn test, and the one-leg stand test. Because these three tests have been recognized by the NHSTA, they carry more weight in court than non-standardized tests, but a skilled attorney can successfully challenge the results of standardized field sobriety tests in court.
Field sobriety tests are meant to measure mental and physical impairment from alcohol use, but many of the so-called signs and symptoms of alcohol impairment stem from physical problems that can be traced to sources other than alcohol.
To convict a driver of DUI / DWI, a jury must be convinced of the driver’s guilt beyond a reasonable doubt. A skilled criminal defense attorney knows that field sobriety tests’ reliance on physical impairment creates problems for prosecutors and creates doubt in the minds of jurors.
This aspect of drunk-driving defense is of critical importance when facing a charge of DUI / DWI: Experts agree that when it comes to alcohol intoxication, mental impairment always occurs before physical impairment. Physical alcohol impairment can be masked in those whose bodies are tolerant of its effects, but mental impairment cannot be masked. If a driver is physically impaired but not mentally impaired, the physical impairment must stem from a source other than alcohol, and a jury must acquit a driver on a charge of driving while impaired.
There are many reasons other than alcohol intoxication that may cause a driver to show signs of physical impairment, including injury, illness, fatigue, or nervousness. A lawyer experienced in defending California DUI / DWI cases will gather a complete medical history from a motorist facing drunk driving cases to determine whether causes other than alcohol may have contributed to any impairment, and challenge the results of any field sobriety test.