DUI & Expert Testimony

Posted on 05-08-2015 by
Tags: Trending News & Topics

A common question that those who have been charged with DUI offenses often pose is whether or not an expert would be helpful to their case. Every case is unique and there are situations where it may be advisable to use a qualified expert to retest samples, prepare a report or testify in court.

While DUI charges are some of the most common criminal cases in Los Angeles County, these cases and the evidence associated with them are usually not simple. Unless the defendant is charged with DUI refusal, proving a charge of driving under the influence requires the prosecutor to establish that the defendant’s blood alcohol content was 0.08 percent or higher at the time he or she was driving a motor vehicle.

Those who are arrested on suspicion of DUI have the option of taking either the breath or blood test. The People have their own expert witnesses, namely toxicologists and other County laboratory employees, who will testify regarding the accuracy and procedures of testing.

There are a number of situations in which a defendant may want to hire his or her own expert witness to challenge and rebut the prosecution’s claims. There may be instances where the accuracy of the blood testing is put into question. In these cases, the defendant can request a blood split order be issued that would allow retesting of the blood sample in an independent laboratory. Anytime a blood sample is taken from law enforcement, part of the sample is stored for evidentiary purposes. Retesting may show that the driver’s BAC was actually lower than reflected on the crime lab reports or it may show that the amount of narcotic or medication in a person’s system was at a level that would not cause impairment. In these cases, the expert may prepare a report or may testify in a live hearing.

There may be other cases where defendant’s BAC on the blood or breath test was higher than the BAC at the time of driving due to the phenomenon of rising blood alcohol level. After drinking, a person’s blood alcohol level will slowly rise, level off and then drop. This means that there may be situations where a driver who had just consumed alcohol prior to getting behind the wheel was actually below 0.08 percent at the time of driving but tested higher at a later time due to a rising blood alcohol level. In these cases, toxicology experts can be brought in to explain to juries the phenomenon of rising blood alcohol and show mathematically how a driver’s BAC was actually below the legal limit at the time of driving.

There may be circumstances where a defendant would need to use the services of an accident reconstruction expert. In cases alleging a DUI collision resulting in injuries or death, an accident reconstruction expert can show how a collision may have been caused by another party or some other factor unrelated to the defendant’s conduct. Their report or testimony may be used in mitigation when dealing with a case involving a serious DUI collision. 

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