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In any California drunk driving case, a motorist usually will be charged with violating two different laws. He or she will be accused of driving under the influence of alcohol (DUI), but will also be charged with violating the "per se" laws. There are important distinctions between the two in the context of a drunk driving arrest. An experienced California DUI / DWI defense attorney can help a driver navigate the court system and launch a defense against both charges.
Where a person is charged with driving under the influence, the focus is the condition of the driver as being either mentally or physically impaired as the result of consuming alcohol, drugs (DUID), or a combination of alcohol and drugs. The legal definition for being "under the influence" in California is similar to that in other states. In order to be considered under the influence, the driver's "physical or mental abilities are impaired to such a degree that he or she no longer has the ability to drive a vehicle with the caution characteristic of a sober person or ordinary prudence, under the same or similar circumstances."
In order to determine whether or not the motorist is under the influence at the time of driving, the prosecution usually will resort to the use of circumstantial evidence. Circumstantial evidence differs from direct evidence in one key way – circumstantial evidence merely implies that something is true. In DUI / DWI cases, one of the facts the prosecutor implies is that the motorist is under the influence of alcohol. Generally the prosecutor will try to introduce evidence of driving patterns, physical observations such as slurred speech, odor of alcohol, unsteady gait, or red eyes, field sobriety test performance, and chemical test results.
Experts in the field agree that when dealing with impairment from alcohol, mental impairment always precedes physical impairment. This is one reason that field sobriety tests are divided attention tests – they seek to determine whether the motorist is suffering from any mental or physical impairment. Aside from the fact that field sobriety tests are inherently unfair – they usually take place on the side of the road with cars whizzing past along with a hundred other distractions – physical impairment alone is not evidence of being under the influence. If a motorist is demonstrating physical impairment, but no mental impairment, then the impairment must be coming from a source other than alcohol. Physical impairment can come from any number of sources.
For example, an arresting officer may cite a driver’s red and watery eyes or inability to stand on one foot as a sign that the driver was under the influence. However, irritated eyes can stem from any number of factors – allergies, fatigue, air pollution, etc. By the same token, an inability to balance on one foot can be attributed to an old injury or just poor balance.
Although many prosecutors want juries to believe that the circumstantial evidence of being under the influence is ironclad, the so-called signs of being under the influence can be attributed to any number of factors. A skilled California drunk driving attorney will take a thorough history from a client to determine if the circumstantial evidence can be attributed to illness, injury, or other conditions that can appear as evidence of impairment, and use that information to help a client win his or her case.