If you drive on California roads, you have already agreed to submit to a chemical test if a law enforcement officer arrests you for DUI. You did not sign anything. The agreement is implied by the act of driving. That is what California's implied consent law means, and most drivers do not know it applies to them until the moment an officer is asking them to blow into a device.
It is important to consult a reliable criminal defense lawyer in California to understand your rights and protect your case under this law. Here is what the law requires, what your options are, and what happens if you refuse.
What Is California's Implied Consent Law?
California Vehicle Code 23612 states that any person who drives a motor vehicle in California is deemed to have given their consent to chemical testing of their blood or breath for the purpose of determining their blood alcohol content or the presence of drugs, if that person is lawfully arrested for driving under the influence.
The law does not require you to consent in the moment. Your consent was given when you chose to drive on California roads. Refusal does not cancel the arrest. It adds consequences.
When Does the Implied Consent Law Apply?
The implied consent law applies after a lawful DUI arrest. The keyword is lawful. An officer cannot demand a chemical test from any driver they stop without legal justification. The requirement is triggered by a lawful arrest based on probable cause that you were driving under the influence.
Before the arrest, during the traffic stop, you may be asked to perform field sobriety tests and to blow into a preliminary alcohol screening (PAS) device. If you are over 21 and not on DUI probation, you are not legally required to submit to the PAS or the field sobriety tests at that stage. Those are pre-arrest investigative tools.
Once you are arrested, the situation changes. Post-arrest chemical testing is required under the implied consent law.
Breath or Blood: Do You Have a Choice?
After a lawful DUI arrest, you have the right to choose between a breath test and a blood test. Officers are required to inform you of this choice. If you choose breath, you provide a breath sample at the station using an evidential breathalyzer, which is more accurate than the roadside PAS device. If you choose blood, a qualified phlebotomist draws a sample that is preserved and tested by a laboratory.
The choice you make has strategic implications. Breath test results are available immediately and used quickly. Blood samples, however, can be independently tested by the defense. Requesting a split of the blood sample allows the defense to have the sample independently analyzed.
If breath testing is unavailable due to a medical condition or equipment issue, blood testing is required. If you cannot provide a breath sample and blood testing is medically inadvisable, a urine test may be used in limited circumstances.
What Happens If You Refuse the Chemical Test?
Refusing a post-arrest chemical test in California carries consequences that are separate from the DUI charge itself and stack on top of it.
DMV consequences for refusal: A first-time refusal results in a 1-year license revocation by the DMV, regardless of how the criminal case resolves. A second refusal within 10 years results in a 2-year revocation. A third refusal results in a 3-year revocation.
These revocations are administered by the DMV through the APS process. You still have the right to request a DMV hearing within 10 days to contest the revocation.
Criminal consequences for refusal: In a criminal case, the prosecution can introduce evidence that you refused the test. California courts have held that refusal can be used as evidence of consciousness of guilt, meaning the jury may be told that you refused and draw inferences from that refusal.
A refusal also eliminates the possibility of challenging the accuracy of a BAC number, since there is no number to challenge. The case shifts to a purely behavioral and observation-based prosecution. That changes the defense strategy significantly.
Does Refusal Mean the Case Is Stronger for the Prosecution?
Not necessarily. A refusal case is different from a BAC case, but it is not automatically stronger. The prosecution still has to prove you were driving under the influence based on officer observations, field sobriety test performance, driving behavior, and other evidence.
We have defended clients in West Covina and Los Angeles County facing DUI charges where the chemical test result was challenged, where the stop was challenged, and where refusal was at issue. The facts of each case determine the defense strategy. If you refused the chemical test after a DUI arrest, that does not mean your options are exhausted.
What Are Your Rights During a DUI Stop and Arrest?
You have the right to remain silent. You are not required to answer questions beyond identifying yourself. Anything you say to the officer about how much you had to drink, where you were, or how you feel can be used in the prosecution.
You have the right to an attorney. After your arrest, you should ask for one. You should not answer substantive questions about the incident without an attorney present.
You are not required to perform field sobriety tests or submit to the roadside PAS device if you are over 21 and not on DUI probation. These are voluntary at the pre-arrest stage.
You are required to submit to a post-arrest chemical test under the implied consent law. Refusing has consequences, but you still have the right to request a DMV hearing and to defend against both the DUI charge and the refusal allegation in court.
Why the Lawfulness of the Arrest Matters for Implied Consent
The implied consent obligation only applies if the arrest was lawful. If the officer lacked probable cause to arrest you, the demand for a chemical test was not legally valid. Refusal in that context may not carry the same consequences, and any test result obtained may be suppressible.
This is one of the first things we examine when a client comes to us after a DUI arrest in West Covina. Tammy Higgins spent 16 years as a public defender across three counties, including her final assignment in the Homicide Defense Unit, before entering private practice. She has tried over 100 criminal cases to a jury verdict. Analyzing the lawfulness of a stop and arrest is foundational to how we approach every DUI case.
Travis J., one of our clients, described his experience: Tammy was patient with him and explained everything in a way that was easy to understand. She took his calls and answered his texts. When it came time to deal with the other side, she was firm and did not take no for an answer.
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