California Breath Testing Laws In A DUI Case

DUI Defense Legal Guide

Implied Consent

California’s harsh driving under the influence (DUI) law includes an implied consent law. This law holds that any person who drives a motor vehicle is deemed to have given his or her consent to chemical testing of his or her blood or breath for the purposes of determining the alcoholic content of his or her blood (BAC), if lawfully arrested for a DUI1

In simple terms this basically means that you agree to a breath, blood, or urine test if arrested for DUI.

The test will be incidental to a lawful arrest and will be administered at the direction of a police officer having reasonable cause that you were driving under the influence of alcohol or drugs.2) The officer is required to inform the driver that refusal to take a breath or blood test will result in an enhancement of penalties in addition to the standard DUI penalties.3

It is important to remember that the implied consent law only applies to blood and breath tests requested after a lawful DUI arrest. You may refuse to take a breath test, also known as a preliminary alcohol screen, prior to your actual arrest4  However, if the officer has reasonable cause to suspect you are driving under the influence based on other evidence such as the field sobriety tests and you are lawfully arrested, you must then submit to a breath test.

Breath Testing FAQs

1)  How will I know if I am under arrest?

If the officer that pulls you over has suspicion that you are driving under the influence, he will conduct a series of field sobriety tests.  As part of these field sobriety tests, he may offer that you take a preliminary alcohol screening test.  You may refuse this hand-held breath test that the officer requests for you to do at this point.  However, if the officer has probable cause to suspect that you are driving under the influence, he should place you under arrest and it is only after that point that you must submit to a blood or breath test.

2) If I believe I was unlawfully arrested, should I refuse to take a chemical test?

If you are placed under arrest, whether you believe it was lawful or not, failure to submit to the implied consent law related test will result in more severe consequences. It is usually easier for your attorney to get the results of an unlawful breath test thrown out by arguing that the arrest was unlawful than it is for your attorney to argue that you refused the breath or blood test based on your assumption that the arrest was unlawful.

3) Is an officer allowed to require me to take a blood test instead of a breath test?

If the officer suspects that you are driving under the influence of  drugs or both alcohol and drugs and places you under arrest, he can then require you to take a blood test. Only a blood test will show whether or not you have been driving under the influence of drugs.

4) I have heard that the hand-held breath tests are unreliable, what can I do about that?

If you are placed under arrest on suspicion of driving under the influence, you will usually be transported to the station to take a different (not hand-held) breath test.   Depending on the time of your breath test and absorption of alcohol in your blood stream you may have a rising blood alcohol defense in your DUI case.

5) What if I have a medical condition that prevents me from taking a breath test?

Having a low lung capacity or a medical disorder that prevents you from submitting to a breath test does not excuse you from taking a chemical test altogether. The officer may take a blood test if you cannot take a breath one.

Related Issues

Refusal to Take Chemical Test  – Your refusal to take a breath or blood test after you have been lawfully arrested leads to specific enhanced penalties for refusing to take the chemical test in addition to the standard DUI penalties. On a first offense DUI, the extra penalties may include two extra days in jail, a one-year license suspension, and a nine-month DUI school.  For a second DUI offense, the penalties may include 96 hours of jail time and a two-year license suspension. For a third DUI offense, the penalties may include 120 days in jail, and a three-year license suspension.

Restricted License – A restricted license allows you to drive to and from your place of employment,  or a driving under the influence program after an initial period of suspension on your license. If you are in a pilot county in CA, you may be required to install an ignition interlock device on any car to which you have access.  If you are required to install the IID, you may drive anywhere, as long as you are operating a vehicle equipped with the IID.  If you are lawfully arrested and refuse to take a breath or blood test, you do not qualify for a restricted license at any point during your suspension and simply are not allowed to drive at all. 

Underage Drivers – If you are underage and refuse to take a chemical test either before or after a lawful arrest, you will face much harsher penalties5 Further, you will not qualify for a restricted license at any point during your suspension.  See also California Laws regarding DUI Charges for underage drivers.

Next Steps

If you have been arrested and would like to learn more about what attorneys charge.

If you want to understand why its important to have an attorney represent you.

If you are ready to discuss a pending case contact the Aizman Law Firm at 818-351-9555 for a free confidential consultation.


  1. California Vehicle Code 23162(a)(1)(A. []
  2. Id. at §23162(a)(1)(c []
  3. Id. at §23162(a)(1)(D []
  4. California Vehicle Code 13353.1. []
  5. California Vehicle Code 13353.1. []

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