Police Evidence
In order to prosecute a person for DUI, the police need to collect sufficient evidence
to prove the driver’s guilt beyond reasonable doubt. Thus, various kinds of
evidence are are obtained during investigations. Among these are as follows:
Driving symptoms. These usually catch the police officer's attention
which may involve swerving between lanes, running while a stop sign, lane straddling
or erratic driving. As recognized by the National Highway Traffic Safety Administration,
there are about 20 different driving patterns which could be possible indicators
of intoxication. However, it is interesting to note that speeding is not one among
these driving symptoms for speeding is said to require better coordination, quicker
judgment and faster reflexes.
Personal behavior and appearance. During a DUI stop, the police will
examine whether the driver is intoxicated which may be evidenced by having odor
of alcohol, disheveled clothing, bloodshot eyes, unkept hair, slurred speech, flushed
face, fumbling with a wallet to get the driver's license, unsteady gait, leaning
on the car for support, difficulty following directions, etc.
Field sobriety tests. These are among the most controversal aspects
of a DUI stop. These may include testing the body’s positioning and balance (also
called the Rhomberg test or the Romberg maneuver), alphabet recitation, horizontal
gaze nystagmus (involves following an object with the eyes, usually a pen), fingers-to-thumb
and hand pat. Although these field sobriety tests have been continually used, only
three of these (walk-and-turn, one-leg-stand and horizontal gaze nystagmus) are
adopted and considered effective by the NHTSA. In some states, only these three
standardized tests are admissible in evidence. In California, however, police officers
continue to administer whichever tests they choose. Undergoing these tests is not
compulsory and does there is no law that punishes anyone who refuses to take them.
Breathalyzer. Known as PAS (Preliminary Alcohol Screening) units,
or EPAS (Evidential Portable Alcohol System), these hand held breathing devices
are supposed to give a very rough indication of the suspect's blood-alcohol
concentration. However, despite their relative inaccuracy, courts have permitted
the admission of evidence at trial. But submission to a PAS test is not legally
required (unless the person is under 21 years of age).
Miranda warning.
This warns the person from making incriminating statements, whether made spontaneously
or in response to questioning. “Every person has the right to remain silent”. The
officer is free to ask incriminating questions during initial investigation before
the Miranda warning is given. A refusal to submit to chemical testing may be interpreted
as an incriminating statement.
Blood and breath test. These tests are given after performing the
other tests and the police officer has reasonable belief that the driver has been
drinking or abusing drugs. The machine called the breathalyzer is susceptible to
numerous problems and often yields inaccurate results. It does not even measure
alcohol, but rather the methyl group in the alcohol compound — and there are thousands
of compounds that contain this group, over 100 of which have been documented on
the human breath. Blood analysis is considerably more accurate, although possible
problems exist there as well, such as fermentation of the sample, coagulation and
lack of sterilization. Urinalysis is the least reliable test for blood-alcohol concentration.