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What Happens After a DUI Arrest in California? Understanding Chemical Tests and Your Rights

Once you are arrested for DUI in California, the investigation changes. At this point, you generally have an obligation to take a chemical test, either a blood or breath test, based on your agreement to obtain a California driver's license.

Understanding what happens with that test, and the difference between a voluntary test and a required chemical test, can be important.

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Blood or Breath Test After a DUI Arrest

After an arrest, an officer will generally tell you that you must take a blood or breath test. You may be given a choice between the two.

Sometimes, however, an officer may describe three options: taking a blood test, taking a breath test, or refusing and having the officer obtain a warrant.

If you refuse the chemical test, the officer may seek a warrant from a judge. The officer would present the probable cause supporting the DUI arrest, and a judge would determine whether a blood draw should be authorized.

A refusal can also have consequences with the DMV, including the potential loss of driving privileges for a year or longer.

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What Happens If You Choose a Blood Test?

Blood testing is more invasive because it involves drawing blood from your body to obtain evidence.

If you agree to a blood test, some police agencies may still obtain a warrant before drawing your blood. The blood must also be drawn in a medically appropriate manner. Typically, a nurse, phlebotomist, or another appropriately trained person performs the blood draw, although procedures can vary by agency.

Some agencies may take you to a hospital for the blood draw.

If a hospital asks you to sign paperwork authorizing the blood draw, that paperwork may be a hospital requirement. Whether signing or refusing such paperwork constitutes a refusal under the law can depend on the circumstances.

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What Happens With a Breath Test?

A breath test is generally less invasive because it requires you to blow into a machine rather than having blood drawn.

If the breath machine does not register a result, you may then be told that you need to provide a blood sample.

Taking either a blood or breath test satisfies the chemical-testing obligation discussed in the video. Refusing the test can create separate DMV consequences.

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What If You Refuse the Chemical Test?

Refusing a chemical test after a DUI arrest can have consequences beyond the criminal case. The DMV may take action against your driving privileges, and a refusal can potentially result in a suspension or revocation for a year or longer.

A refusal may also be addressed in court in some circumstances.

However, the consequences are different from refusing voluntary field sobriety tests. The discussion explains that voluntary field sobriety tests involve different constitutional considerations, while the chemical test required after arrest is subject to separate rules.

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What If Other Substances Are Found?

A blood test does not necessarily only look for alcohol.

If you had alcohol in your system along with other substances, such as drugs, prescription medication, or marijuana, the blood can also be tested for other substances.

Even if the blood alcohol concentration is below .08, the presence of other substances may become part of the investigation. The prosecution may argue that the combination of alcohol and other substances caused impairment.

If the blood alcohol level is low and there are no other relevant substances or evidence, the DUI case may not proceed based solely on driving under the influence. However, the DMV can still address a chemical-test refusal separately.

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Can You Challenge Police Conduct?

Your constitutional rights can be waived through consent. If you voluntarily consent to a search, provide information, or agree to a test, you may be giving up the ability to object to that particular action.

For that reason, it can be useful to ask whether something an officer is requesting is required or voluntary.

If an officer tells you that something is required when it is actually voluntary, that statement may become relevant when challenging the evidence later.

For example, if an officer says you must perform a field sobriety test when the test is actually voluntary, the circumstances surrounding your participation may become important in court.

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What If Police Did Not Have Probable Cause?

A DUI arrest still requires probable cause. Police need sufficient evidence to justify the arrest based on the information available at the time.

For example, an officer cannot simply stop someone because the officer wants to talk to them about suspected DUI. There must be a lawful basis for the stop.

However, if someone calls police and reports that a person is driving under the influence, that information may provide a basis for police to stop the vehicle and investigate, even if the driver has not committed another traffic violation.

Ultimately, the police conduct leading to the arrest can be challenged in court. If the officer did not have the required basis for the stop or arrest, the resulting evidence may potentially be challenged.

Understanding what happened at every stage, from the initial stop through the chemical test and arrest, can therefore be important when defending a California DUI case.

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