Chemical testing is a major concern in all DWI arrests. Even though there are many challenges to the validity of blood, breath and urine tests in drunk driving cases, people are often under the mistaken idea that if the machine says someone is above the legal limit, they are guilty, period.
Fortunately for those who stand accused of DWI, a chemical test that indicates a driver was over the legal limit doesn’t mean an automatic conviction. However, a skilled drunk driving defense attorney will need to be well-versed in the various attacks on breath testing, on blood testing, and on urine testing for alcohol and drugs.
Most jurisdictions charge Driving Under the Influence (DUI) in two ways: Violation of the “common law” drinking and driving laws, and violation of the “per se” laws. Common law drunk driving is concerned with whether the driver is impaired by alcohol or drugs, and is unable to operate their car with the same caution as a sober person because they have consumed alcohol or drugs. Violation of the per se charge does not depend upon the person being affected by alcohol or drugs; instead, the per se charge relates to the blood or breath alcohol content (BAC) as being above the legal limit, now .08 percent in all 50 states.
Chemical testing of the blood, breath or urine to determine BAC is obviously at the heart of the per se charge, where the defendant is accused of driving above the legal limit. However, chemical testing for alcohol levels is also a critical inquiry in the traditional DUI / DWI case, where the driver’s condition as being impaired or not is the central question. This is because the forensic alcohol experts in most states will offer an opinion that all individuals are impaired once they are above a certain BAC. Some experts believe that alcohol level to be .10 percent, some .08 percent, and the most conservative will opine that all people are under the influence for DUI / DWI at a .05 percent BAC. Therefore, it is vital that a DUI / DWI defense lawyer be able to successfully address these issues to advance their client’s cause.
Chemical testing in DUI / DWI cases is of such importance that both the Department of Motor Vehicles (DMV) and criminal courts have imposed harsh sanctions where the driver accused of drinking and driving refuses to submit to chemical testing when lawfully requested by a peace officer following a DUI / DWI arrest. In California, for example, a refusal to test following a drunk driving arrest may result in a driver’s license suspension of one-year for a first offense DUI / DWI. This is in the DMV’s action, and is separate and apart from any action taken by the court. In the court case, refusal to 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 test as consciousness of guilt (if the case proceeds to a jury trial).
Chemical testing in drunk driving cases or DUI drug arrests involves the testing of bodily fluids – blood, breath, or urine. (There have been some efforts to develop a saliva test, but this has not yet been put into use.) In most states, when someone is accused of driving under the influence of alcohol, he or she has a right to take either a breath or a blood test. (In some states, it is the arresting officer that has the right to select which test the subject will take.) Where driving under the influence of drugs is suspected, the chemical test choices will usually include blood or urine. Generally, there is no right to a urine test in DUI / DWI cases relating to alcohol. Urine testing in drinking and driving cases has been deemed too unreliable to withstand courtroom challenges.
It’s important to note that while chemical testing may be accurate to determine blood or breath alcohol content (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 while in a police station; the crime is driving under the influence, or 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 for alcohol (DUI / DWI) or drugs (DUI drugs or driving under the influence of drugs) is not always accurate – far from it. There are challenges to roadside breath tests (also known as PAS or PBT tests), stationhouse breath tests, forensic blood tests, and forensic urine tests. Testing in DUI drugs cases 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 are no “per se” limits in drug cases, and because of the time in which many drugs stay in the system, it is incredibly difficult to demonstrate that a person was impaired at the time of driving.
Although many drivers accused of drinking and driving may believe that a chemical test result with a BAC over .08 percent means a sure conviction, that’s not the case. However, it’s imperative to consult with a criminal defense attorney with experience fighting DUI / DWI cases. A skilled attorney can challenge the results of blood, breath, or urine tests, and plan a strategy to fight a drunk driving case.
Alcohol Absorption & Elimination
The Breath Test at the Precinct
Forced Blood Draws
