California DUI Defenses
California Vehicle Code Sections 23152 and 23153
Driving Under the Influence

Just because you suffer a California DUI arrest doesn't mean you have to suffer a California DUI conviction.  There are countless defenses that experienced California drunk driving attorneys know how to successfully employ.  Below is a brief description of the 10 that are most commonly argued.

1. Sober People are Guilty of Bad Driving Too

When prosecuting a California driving under the influence (DUI) case, one of the first things that DUI prosecutors focus on is your driving pattern.  They routinely have the DUI arresting officer testify that you were "driving in a manner consistent with someone who was under the influence of alcohol or drugs".  Most often times this so-called "pattern" includes allegations that you were speeding or weaving within your lane.

An experienced DUI lawyer rebuts this evidence by having the officer testify about all of the ways that you drove properly and safely.  A DUI attorney will elicit testimony from the arresting officer that (1) the majority of traffic violations are committed by sober people, and (2) "speeding" and a variety of other violations that police frequently cite as the reason they initiated a DUI stop aren't recognized by the National Highway Traffic Safety Administration (NHTSA) -- the nation's leading authority on DUI -- as characteristic of drunk driving.

  • Example:  Tony was driving on the 405 Freeway after having a late-night drink with a friend.  While he reached over to change out a CD, he drifted into the next lane, was pulled over by the California Highway Patrol (CHP), and then arrested for DUI.
Tony's DUI defense attorney would have the officer testify that Tony was otherwise driving fine.  Tony was driving within the speed limit, pulled over as directed, parked without difficulty, and had no other problems controlling his car.further evidence that Tony was driving with "the caution characteristic of a sober person".  His California DUI attorney would additionally have the officer admit that sober people regularly drift into other lanes because they're tired, eating, reading, talking on their phone, and/or are otherwise distracted due to issues having nothing to do with drug or alcohol consumption.
2. Objective Symptoms of Intoxication Are Anything But Conclusive

Your physical appearance plays a big role in your California DUI investigation.  The officer who arrested you for DUI will undoubtedly testify that you were "under the influence" because you had


  • red-watery eyes,


  • slurred speech,


  • a flushed face,


  • the strong odor of alcohol on your breath, and/or


  • an "unsteady gait".

Incidentally, these "objective signs and symptoms of intoxication" are all listed on a pre-printed DUI arrest form used by the CHP, the Los Angeles Police Department (LAPD), and a variety of other local law-enforcement agencies.  These DUI arrest reports allow an officer to simply "check off" that you displayed these signs / symptoms without any further elaboration.

A skilled DUI lawyer defends you by addressing all of the "innocent" explanations that could have led to those signs.allergies, fatigue, eye irritation, embarrassment, frustration, nerves.and that drinking in and of itself (and therefore smelling of alcohol) doesn't amount to driving under the influence.

A knowledgeable DUI attorney will elicit testimony that actual alcohol, in fact, has no odor.  The jury will hear that there's no way to tell by smell alone if you've been drinking virgin drinks, non-alcoholic beer or liquor-based cocktails.

  • Example:  Sheriff Smith testified for the Orange County District Attorney that Sam had red-watery eyes, a flushed face and smelled of alcohol when he was pulled over at 10 p.m. on a Saturday.  On cross-examination by Sam's Newport Beach DUI defense lawyer, Sheriff Smith admitted that although he was the "investigating" officer, he never even took the time to question Sam about his physical appearance.  As it turned out, Sam had been playing beach volleyball all day in the sun (which accounted for his red eyes and flushed face), and had been drinking both Coronas and O'Doul's (which explained the odor on his breath).
3. Field Sobriety Tests (FSTs) Don't Accurately Measure Impairment

Field Sobriety Tests (FSTs) are heavily relied on by the "prosecution team" -- made up of the prosecutor, the arresting officer, and the DUI criminalist -- to almost always conclude that you were guilty of drunk driving.  The arresting officer will testify that you "performed poorly" on these tests, as you were unable to follow his/her "simple" instructions based on your impairment.

Your DUI defense lawyer will explain that your natural physical coordination, nerves, and a variety of other issues play a huge role in these "balance and coordination" exercises.  A seasoned DUI defense attorney will also get the investigating officer to admit to the fact that the number of things you did right while performing your FSTs far exceeded the number of things that you did wrong.once again highlighting the officer's true bias against you.

  • Example:  LAPD officer Bob told the jury that Lisa performed poorly on her FSTs.  On cross examination, Lisa's Los Angeles DUI lawyer elicited testimony that Lisa performed her FSTs on Sunset Boulevard right outside a busy bar with a line of people watching.  It was cold and windy, cars were speeding by, and Lisa was in 3-inch high heels.  Lisa's DUI attorney made it clear to the jury that all of these factors contributed to her "poor performance", none of which were alcohol related.

The field sobriety tests that the arresting officer had you perform will also likely be called into question, as most officers don't stick to the "NHTSA 3 Standardized Field Sobriety Tests (SFSTs)".and even if they do, the officers typically don't properly administer or evaluate them.

4. The Police Officer Didn't Conduct a Proper 15-Minute Observation Period

California DUI law mandates that before an officer gives you a "breath test," he/she must continuously observe you for fifteen minutes.  During this time, you are not supposed to eat, drink, vomit, belch, burp or smoke, as doing so may affect the results of your test.  The reason this is so important is because if you do any of these things.and alcohol moves from your stomach to your mouth.your blood alcohol content (BAC) might be inaccurately high.

A seasoned DUI defense attorney knows how to discredit the officer's 15-minute observation period.  Most officers conduct this observation period when they're completing paperwork and/or while they set up the breath test machine.  An improper 15-minute observation period also enhances the argument that the officer wasn't following proper procedures while conducting the entire driving under the influence investigation.

  • Example:  Rancho Cucamonga Sheriffs Deputy Sam testified that he "continuously observed Tim for 15 minutes and that during that time nothing unusual happened".  On cross-examination, Tim's Rancho Cucamonga DUI defense attorney brought out the fact that the 15-minute period took place while Officer Sam drove Tim (who was riding alone in the backseat) to the police station.  Tim's DUI lawyer revealed that an observation period conducted in that manner wouldn't have enabled Officer Paul to see Tim burp, belch, hiccup, or regurgitate.any of which could have arguably triggered a falsely high "mouth alcohol" BAC result.
5. The Officer Didn't Comply With California's Title 17 Regulations That Govern Blood and Breath Testing

California's Code of Regulations Title 17 is what governs how DUI blood and breath tests are conducted.  It sets forth all of the requirements that are necessary for an officer to properly maintain the integrity of a blood or breath test.  Title 17 applies to

  • The 15-minute observation period (described above),


  • The actual administration of the tests,


  • The maintenance of the testing instruments used, and


  • The collection, handling, and storage of the tests (when blood or, in rare instances, urine, is tested)

When an officer fails to conform precisely to these standards and regulations, an experienced DUI defense lawyer knows the most effective ways to call your entire DUI investigation into question.


  • Example:  After the Ventura District Attorney examined her expert witness -- the DUI criminalist -- the jury heard that Rick's blood test revealed a 0.10% blood alcohol content (BAC).  During the criminalist's cross-examination, Rick's Ventura DUI attorney elicited testimony that (1) the preservative contained in the vial used to collect and store the blood sample had expired, and (2) the arresting officer didn't properly shake or store the sample.  Rick's DUI lawyer was able to convince the jury that those facts could have invalidated his 0.10% result.
6. Mouth Alcohol Led to a False High BAC Result

"Mouth alcohol" is just that.alcohol that remains in the mouth.  Although stationary DUI breath testing machines and Preliminary Alcohol Screening (PAS) devices are supposed to collect air from your deep lungs (called alveolar air or referred to as "deep lung air"), residual mouth alcohol can interfere, which leads to a false high BAC reading.

Additionally,

  • Gastroesophageal Reflux Disease (GERD), acid reflux, and heartburn,


  • Medicines containing alcohol (many cough syrups, for example),


  • Mouth spray or mouthwash, and/or


  • Dental work that causes food to remain trapped between your teeth

can also produce mouth alcohol, resulting in a BAC much higher that what is truly in your system.


  • Example:  During her examination, Becky admitted to having a couple of glasses of wine earlier in the evening.  She explained to her Pasadena DUI lawyer that she regularly suffers from heartburn.and was suffering the night she was arrested.which embarrassed her because she kept burping when the officer was trying to administer the Preliminary Alcohol Screening (PAS) device.
Becky's drunk driving defense attorney called a DUI toxicologist to the witness stand who testified that heartburn and the consequential act of burping could in fact produce "mouth alcohol".  The witness further explained that Becky's "mouth alcohol" likely resulted in a much higher BAC than what only two glasses of wine earlier in the evening would have produced.
7. You Were "On the Rise"

Let's be clear -- there is nothing illegal about drinking before you drive, so long as you're not impaired at the time you are driving.  Alcohol takes a while to absorb into your system.  Just because you drink alcohol doesn't mean you'll immediately feel its effects.

While the alcohol is absorbing, your blood alcohol content is "rising".  Although this process takes an average of about 50 minutes, it can last as long as three hours from the time you finish your last drink.  It doesn't matter what your BAC was when you're back at the station, after having gone through a lengthy drunk driving investigation -- it matters what your level was at the time you were driving.  Period.

  • Example:  Sheila had a few shots with her friends at a Palm Springs bar very close to her house.  She left to go home almost immediately after she drank.  When she was stopped by a local sheriff due to a burnt out taillight, she was investigated for DUI because the sheriff smelled alcohol coming from her breath.
By the time she performed her field sobriety tests.which of course, the sheriff said she performed poorly.she was taken to the station and submitted to a breath test, where she "blew" a 0.09%.  Sheila's Palm Springs DUI defense lawyer elicited testimony from the prosecutor's expert that Sheila's absorption process probably wasn't complete when she drove home.  Jurors heard that at the time of driving, it was very likely that Sheila's BAC was below the illegal 0.08%.
8. You Weren't DUI if You Were Mentally Alert

Although officers routinely testify that DUI suspects displayed physical signs of impairment, they usually don't testify that defendants displayed signs of mental impairment.unless, of course, the person was obviously and undeniably intoxicated.

The disconnect here is that mental impairment always precedes physical impairment.  Depending on the facts of your drunk driving arrest, a savvy DUI lawyer will elicit testimony that a person who displayed signs of physical impairment (but not mental impairment) probably had some other explanation for their driving and behavior that wasn't alcohol related.

  • Example:  John, who was pulled over in Long Beach because he was holding his cell phone while driving, was polite, coherent, appropriate when responding to questions, and followed all instructions when performing his FSTs.  He was, however, a bit off-balance, couldn't quite stand still, and was fidgety in general.
The toxicologist that John's Long Beach DUI defense attorney retained testified that even though John had a couple of beers, it wasn't the alcohol that was affecting him physically, since he showed no signs of mental impairment.  Medicine, sickness, nerves, or a host of other issues could have contributed, but it was very unlikely that John was driving under the influence when he was otherwise mentally alert.
9. The Arresting Officer(s) Didn't Follow Proper Procedures

A California drunk driving investigation is supposed to be safeguarded by a large number of procedures that the officer must follow in order for you to be convicted of DUI.  These range from the "probable cause" that is required before an officer can conduct a traffic stop, to reading you your "Miranda" rights prior to questioning you, to following California's Title 17 regulations.

A knowledgeable DUI attorney knows these exact procedures and how to have evidence excluded and/or cases dismissed when they're not followed.  California DUI lawyers will conduct "suppression hearings" otherwise known as "Penal Code 1538.5 hearings" if (1) they don't believe the officer had the right to stop you in the first place, and (2) to have a "pre-trial" opportunity to question the officer and illuminate holes in the prosecution's case.

  • Example:  After being arrested for DUI, Officer Joe -- who didn't advise Lucy of her Miranda rights -- asked Lucy how much she "truthfully" drank and why she drove.  Lucy's Riverside DUI attorney knows that any questions that were asked
    1. after Lucy was arrested, and


    2. were asked to elicit incriminating responses
are illegal if they were posed without first advising Lucy that she had the right to remain silent.
Lucy's diligent DUI lawyer ultimately convinced the Riverside D.A. to reduce the DUI charge to reckless driving based on (1) Officer Joe's unlawful interrogation, and (2) other "questionable" tactics that Officer Joe employed, which were revealed when Lucy's DUI attorney cross-examined Officer Joe during the suppression hearing.
10. Despite Being At or Above 0.08%, BAC Levels Aren't Always Accurate

Although it may seem pointless to fight a California DUI where it appears like the officer did everything "by the book" and your BAC was at or above a 0.08%, DUI attorneys know that EVERY drunk-driving case can and should be examined for defenses:

  • The breath-testing instrument that was used to collect your sample might not have been properly calibrated or may have had a technical error.


  • Your blood sample may have been passed outside the proper "chain of custody".


  • Your personal breath temperature might be outside the "norm" making it so the breath testing machine didn't accept a proper sample.

These are all defenses that could be raised to save you from being convicted of a DUI.

Example:  Mitch was arrested by a very nice officer, "blew" a 0.11% and knew he had 4 drinks during a long dinner prior to driving, even though he didn't feel like he was under the influence by the time he drove.  A friend convinced him to contact an Anaheim DUI attorney.
Mitch's DUI lawyer reviewed all of the records that pertained to the particular breath-testing instrument used that was used on Mitch.  The attorney discovered that there had been a "maintenance required" flag on that machine the day prior that hadn't been taken care of.  After discussing the case with Mitch, he further discovered that Mitch was on a low-carb diet at the time of the offense which could also produce a BAC higher than what was truly in his system.  After deciding to fight his case, Mitch was acquitted.

Driving under the influence is an area of the law that is complex, scientific, and technical.  An attorney who doesn't routinely defend these types of cases will put you at a severe disadvantage when it comes to truly understanding the science and laws that make this type of case so truly unique and entirely possible to defend.

Call us for help
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If you or loved one is in need of help with fighting a DUI case and you are looking to hire an attorney for representation, we invite you to contact us at Shouse Law Group. We can provide a free consultation in office or by phone. We have local offices in Los Angeles, the San Fernando Valley, Pasadena, Long Beach, Orange County, Ventura, San Bernardino, Rancho Cucamonga, Riverside, San Diego, Sacramento, Oakland, San Francisco, San Jose and throughout California.

If you or a loved one has been arrested for a California DUI, we invite you to contact us at one of our conveniently located DUI law offices to discuss your case and explore all possible defenses.

Return to Drunk Driving

For information about Nevada DUI defenses, go to our article on Nevada DUI defenses.

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