Proving a DUI Case in Court

When a driver is arrested on suspicion of driving under the influence of alcohol or drugs, he or she will typically be cited out and given a future court date for arraignment. All defendants who have been charged with a DUI offense are entitled to a trial. At trial the prosecutor handling the case would be required to prove that the defendant is guilty beyond a reasonable doubt. In a DUI case, prosecutors rely on traditional witness testimony as well as scientific evidence in proving their case against the defendant. The defense can challenge the People’s evidence and mount an affirmative defense. Ultimately, the judge or jury will determine whether or not to convict or acquit the defendant of the DUI offense.

In order to prove that a defendant is guilty of driving under the influence of alcohol in violation of California Vehicle Code Section 23152(a) VC, the prosecutor must be able to establish that the defendant drove a vehicle and that when the defendant was driving, he or she was under the influence of alcohol.

If the defendant has been charged with driving with a blood alcohol content of 0.08 percent or higher pursuant to California Vehicle Code Section 23152(b) VC, the prosecutor must be able to prove that the defendant drove a motor vehicle and at the time of driving, the defendant had a blood alcohol level that was 0.08 percent or more by weight. In order to convict a defendant, the prosecutor must prove each element beyond a reasonable doubt.

In proving a DUI case, the prosecution will have to present the evidence against the defendant. The prosecution will do this by calling witnesses to testify against the defendant. Typically the officers who observed the defendant’s driving conduct, performed the field sobriety testing and conducted the breath or blood testing will be called as witnesses to introduce evidence against the driver. In addition, the prosecutor may call the lab technicians who performed the blood test or expert witnesses to explain how the breath and blood tests work and how they are used to show the defendant’s BAC at the time of driving.

In some cases, the prosecutor may call civilian witnesses to testify. This would include people who may have observed the defendant driving or those who witnessed a traffic collision.

The defense can challenge the evidence and witnesses presented in court by the prosecution. The defendant’s attorney can cross-examine witnesses and challenge the accuracy of the breath and blood testing. In many cases, the prosecutor may rely on retrograde extrapolation to explain how a chemical test taken hours after driving can be used to determine BAC at the time of driving. The defense can also call expert witnesses to show why the testing or assumptions made may be inaccurate or may not take into consideration medical conditions or other factors that may exist. The prosecutor would get an opportunity to cross-examine the defense witnesses and may call their own experts to rebut the defense theory. Ultimately, the judge or jury would determine whether or not the prosecution has met their burden in proving guilt beyond a reasonable doubt.

If you or a loved one have been arrested in California for a DUI offense, it is crucial that you speak with an experienced criminal DUI attorney right away. As a former Deputy District Attorney with over 14 years of prosecutorial experience, Michael Kraut is highly regarded as a top DUI attorney who understands how to effectively fight DUI charges in court and before the DMV.

For more information about proving a DUI case in court, and to schedule your free consultation, Mr. Kraut can be reached 24/7 at (323) 464-6453.