While each DUI case is factually different, the similarities are undeniable. The evidence against you consists generally of driving, personal observations of the officer(s), statements you have made, the field sobriety tests, and the chemical test. Of these, the single strongest piece of evidence is the chemical test followed by the driving and then the others.
The fact that you were driving is one of the central elements of the charge. In fact the prosecution must be able to prove beyond a reasonable doubt unanimously to 12 jurors that you were driving when the offense occurred. More often than not it is your driving that first attracts the officer's attention in the first place. There are a number of driving patterns recognized by the National Highway Traffic Safety Administration (NHTSA- see the complete listing in the FAQ section of this website) that might be indicative of a DUI driver. It is not only the classic serpentine weaving (which of course is the strongest evidence) that supports a prosecution for DUI. Officers are trained at the academy to expect a DUI driver from any traffic stop they perform, especially at late night.
If you were in an accident or otherwise not observed driving, the police must be able to prove that you were driving by circumstantial evidence. In this situation since you were not observed personally driving the police look to other indication that you were recently driving such as (but not limited to) if the hood of the vehicle is warm to the touch, if there are any other potential drivers in the area (specifically if you made any admissions to driving), if you are the registered owner of the vehicle, if you have possession of the keys, if the vehicle drivers seat is adjusted to your size. Although direct evidence is preferred, strong circumstantial evidence can be quite compelling.
After the driving pattern, the officer's next chance to accumulate evidence is the first personal observations of you. This includes any odor of alcoholic beverage, flushed face, bloodshot/watery eyes, speech problems (slur or slow), difficulty handling or locating requested documents (license, proof of insurance, registration) and unsteady gait. If the officer has not already made up his or her mind that you are DUI just on your driving, it is the rare case when the officer still has an open mind after recording these observations.
Next the officer will usually conduct a pre-field sobriety test interview where you will be asked a number of incriminating questions- all without the benefit of an attorney to advise you. The avoidance of the Miranda admonition involves a little legal hairsplitting as you are not technically in custody at the time of the questioning, and Miranda only applies to custodial interrogations. These questions commonly include how much you had to drink and when, how much you had to eat and when, if anything is wrong with your car, do you feel the effects of the alcohol, and if you are under the care of a doctor to name a few of the topics. These questions are again designed to accumulate evidence (and limit your defenses), and you have a right to respectfully decline to answer all but the essentials on who you are.
The field sobriety tests (FSTs), more aptly named roadside agility tests, are commonly conducted under conditions averse to passing them. With traffic speeding by, on uneven surfaces, in all kinds of weather, the FSTs are inherently unfair to the participant from the start. There are over 20 tests that officers have used as FSTs, (see the complete listing in the FAQ section of this website) some clearly are more valid indicators of sobriety than others. Only three of the known FSTs have been recognized by NHTSA as valid enough indicators to be included in a "standardized battery" of tests. The NHTSA recommended tests include the "walk the line", "one leg stand", and nystagmus tests. The nystagmus eye test measures the degree of involuntary eye movement when the subject tracks an object held about one foot from the head as it moves from side to side.
The last piece of evidence accumulated by law enforcement is, by most accounts, the most damaging. Little has more effect on the mind of the prosecuting attorney, judge or jury than the stark number of the over-the- limit chemical test, or sometimes the lack thereof in the case of a refusal to take the test. The chemical tests include the road side breath test (technically called the preliminary alcohol screening device (PAS)), which is finding its way more often into evidence, the intoxilizer breath test, blood test (chromatograph), and less often the urine test, which was discontinued in 2000 because of accuracy problems. For a discussion of these tests see the FAQ section of this website.
The content of this website is for informational purposes only and is not to be relied upon as legal advice. Viewing this website does not create an attorney-client relationship with P. David Wool. Legal representation will only be established upon receipt of a legal services agreement and full compliance with its terms. The information contained on this website is based on current California state law only and can change over time. Laws vary from state to state. Do not rely upon the content of this website as legal advice. Contact a lawyer at once if you have a legal matter.