Circumstantial Evidence in DUI Cases

Posted on 04-27-2015 by
Tags: Trending News & Topics

When people think about the evidence used in DUI cases, they usually focus on the results of the breath and blood tests. These test results are very important and prosecutors and the DMV rely on these results to demonstrate that a driver was over the legal limit (0.08 percent BAC).

However, there may be circumstances where a defendant is effectively able to challenge the chemical test results. In these cases, there is still a question as to whether impairment can be shown through other circumstantial evidence. A recent California Supreme Court decision implies that the DMV and courts can rely on other evidence when considering a DUI case or potential license suspension.    

While it may appear that chemical test results provide clear-cut evidence of intoxication, this is not always the case. It is important to remember that a breath or blood test only gives an indication of a driver’s blood alcohol content at the time of testing and not at the time of driving. Because of how alcohol is absorbed by the body after being consumed, it is possible for a person who tested over the limit to have had a BAC under 0.08 percent at the time they were actually driving. In some cases, a defendant can have an expert witness provide testimony regarding the phenomenon of rising blood alcohol to rebut the 0.08 allegation.

In the recently decided Coffey v. Shiomoto case, a driver used an expert to show that her BAC was likely below the legal limit at the time of driving and that she only had a higher BAC at the time of testing due to a rising blood alcohol level. The prosecution agreed to dismiss the DUI and the defendant pleaded to wet reckless in violation of California Vehicle Code Section 23103/23103.5. However, the driver still had to contend with the potential DMV suspension. The DMV requires a minimum four month suspension for drivers who are arrested for a DUI offense completely independent of what happens in court.

The DMV in this case ruled against the driver. Despite expert testimony regarding the rising blood alcohol level, the hearing officer relied on the police officer’s observations of the driver’s red eyes, odor of alcohol and poor performance on the field sobriety tests to support the conclusion that the driver was impaired.

In siding with the DMV, the California Supreme Court ruled that the DMV was justified in considering other circumstantial evidence of intoxication when issuing its decision. In practice, prosecutors and judges will often consider this type of circumstantial evidence when evaluating a DUI case.

In many cases, impairment can be shown by driving conduct, demeanor, physical symptoms of intoxication and performance on field sobriety tests.  It is important to note that a typical DUI defendant is usually charged with both driving under the influence in violation of California Vehicle Code Section 23152(a) and driving with a BAC of 0.08 or higher in violation of California Vehicle Code Section 23152(b), which allows prosecutors to pursue different theories of the case. It remains to be seen what effect this new decision will have on future DUI cases and DMV administrative proceedings.

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