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California’s Implied Consent Law and the Consequences of Refusing Chemical Testing


When someone is arrested for a California DUI offense, the arresting officer will likely ask them if they will consent to a chemical test of the driver’s blood, breath, or urine. Under California law, when a motorist is arrested for suspicion of driving under the influence of drugs or alcohol “is deemed to have given his or her consent to chemical testing of his or her blood or breath for the purpose of determining the alcoholic content of his or her blood.” There is a similar provision for the suspicion of driving under the influence of drugs. Collectively, these are referred to as California’s implied-consent statute.

At its most basic, an implied-consent statute gives law enforcement the ability to test a person’s blood or breath after they have been arrested for suspicion of impaired driving. Of course, police officers are not entitled to physically force a motorist to provide a sample, so the importance of the implied-consent statute is that motorists who refuse testing can be subject to administrative and, in some cases, additional criminal penalties.

Before police are able to rely on the implied-consent statute, it must be established that the motorist was “lawfully arrested” for suspicion of impaired driving. Additionally, the motorist must be provided with certain warnings. If a motorist’s arrest is not lawful, or the police officers involved in the case fail to follow the proper protocol, any evidence or test results obtained may be suppressible.

What Happens if a Driver Refuses a Chemical Test?

If a motorist refuses to provide a sample after a lawful arrest, the defendant will still likely be charged even though there are no test results indicating they were under the influence. Rather than test results, the prosecution will rely on other indicia of intoxication. In addition, the court may provide the jury with a special “consciousness of guilt” instruction. Specifically, the court will instruct the jury that the defendant’s refusal may be considered as consciousness of his own guilt. Essentially, the court will leave it up to the jury to determine why the defendant refused the test, but the court will permit the jury to infer that the defendant refused because he was intoxicated. Importantly, the court must instruct the jury that it cannot find the defendant guilty solely on the basis of a refusal.

Have You Been Arrested for a California DUI?

If you have recently been arrested for a California DUI, contact the dedicated California criminal defense attorney John W. Noonan for assistance. Attorney Noonan is a veteran criminal defense attorney who has over 55 years of experience representing clients who have been charged with all types of California DUI crimes. To learn more about how Attorney Noonan can help you defend against the charges you are facing, call (925) 886-4281 to schedule a free consultation today.