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Chemical Testing

Chemical testing is a central factor in every California Driving Under the Influence (DUI) case. Prosecutors rely heavily on chemical test results, but they can also be useful to the defense. The good news is that a chemical test result that indicates the driver was over the legal limit doesn't necessarily mean an automatic conviction.  There are many challenges to the validity of blood, breath and urine tests in DUI cases. An experienced California DUI defense attorneys from the Law Office of Robert Tayac have the expert technical support and proven strategies to attack the results of chemical tests in a drunk driving cases.

In order to effectively challenge chemical test results, a drunk driving defense attorney must be well-versed in the various attacks on breath, blood, and urine testing for alcohol and drugs.

California DUI arrests result in two separate charges: Violation of the "common law" drinking and driving laws, and violation of the "per se" laws. Common law drunk driving, or driving under the influence, centers on whether the driver is impaired by alcohol or drugs and unable to operate a vehicle with the same caution as a sober person. Violation of the per se charge does not focus on whether the driver was affected by alcohol or drugs; instead, the Per Se charge relates to the blood or breath alcohol content (BAC) being above the legal limit, now. 08 percent in all 50 states.

A chemical test of the blood, breath or urine to determine BAC is obviously the crux of the Per Se charge where the defendant is accused of driving above the legal limit. However, chemical testing for alcohol levels is also critical to the traditional DUI case, where the central question is whether or not the driver was impaired. This is because many forensic alcohol experts believe that all individuals are impaired at a certain BAC. Some experts believe that level to be .10 percent, some .08 percent, and the most conservative will assert that all people are under the influence at .05 percent BAC. Therefore, it is vital that a DUI defense attorney be able to successfully address these issues to advance their client's cause.

Chemical testing is so fundamental to every DUI case that both the California DMV and the criminal courts impose harsh sanctions on drivers who refuse to submit to a chemical test following a DUI arrest. In California, for example, a refusal to a chemical testing following a drunk driving arrest may result in a driver's license suspension of one-year for a first offense DUI. In a criminal court case, refusal to take a chemical test is a "special allegation" that, if proven, results in mandatory jail terms, lengthier alcohol education programs, and a jury instruction that allows jurors to consider the refusal to take a test as consciousness of guilt.

Chemical tests in cases of Driving Under the Influence of alcohol or DUI drug arrests involve the testing of bodily fluids - blood, breath, or urine. In California, as in most states, a motorist accused of Driving Under the Influence of alcohol has the right to choose either a breath or a blood test. Where driving under the influence of drugs is suspected, the chemical test choices are blood or urine. Generally, there is no right to a urine test in DUI cases involving only alcohol. Urine testing in DUI cases has been deemed too unreliable to withstand courtroom challenges.

It's critical to note that while chemical testing may be accurate to determine BAC at the time of testing, it is not conclusive evidence of BAC at the time of driving. It is not illegal to be above the legal limit in a police station hours after being behind the wheel; the crime is driving above the legal limit, not having a BAC above the legal limit at a later time. Because alcohol levels change over time, this is a critical point to understand.

Chemical testing in a DUI arrest is not always accurate - not even close. There are challenges to roadside breath tests (known as PAS or PBT tests), forensic blood tests, and forensic urine tests. DUI drugs testing is even more challenging than testing for alcohol levels in a drunk driving case. Drug tests involve searching for metabolites in the blood or urine, and not the drug itself. Plus, there is no "Per Se" limit in drug cases, and because of the amount of time that many drugs stay in the system, it is incredibly difficult to demonstrate that a person was impaired at the time of driving.

Even though many drivers accused of a DUI believe that chemical test results with a BAC of .08 percent or greater means a sure conviction, that's just not the case. However, it's imperative to consult with a California criminal defense attorney with experience fighting DUI cases. A skilled attorney can challenge the results of blood, breath, or urine tests, and plan a strategy to fight the charges.

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