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Top 20 California Dui Defenses


Top 20 California DUI Defenses

Dealing with a DUI charge in California can seem daunting, but don’t worry – you’re not alone. This post will outline the top 20 defenses you and your DUI defense attorney can use to fight your DUI charge. No matter what situation you find yourself in, these tips can help improve your chances of successfully beating a DUI. So read on and learn more about how to build the best defense for your case.

What is the Best Defense for a DUI?

The best defense depends on the facts of your situation. One might say that the best defense for a DUI is the one that achieves the most positive results for the defendant. In one case, the best DUI defense might concern a challenge of the traffic stop itself, if the police officer did not have reasonable cause to pull over the driver. In another case, the best DUI defense might concern a breathalyzer generating false positive results. 

There are numerous possible defenses to drunk driving charges. We will go over 20 of them in this article, but please be aware that the circumstances of your DUI arrest could create the possibility of additional legal challenges. You should never give up hope and just plead guilty to a DUI without exploring legal defenses and trying to get the charges dismissed or negotiated to a less serious offense.

20 Legal Defenses for Fighting California DUI Charges

We will go into these concepts in greater detail below, but here are 20 of the most common legal defenses that people use when they are trying to fight DUI charges in California. 

  1. Mistakes in DUI blood tests;
  2. Violations of Title 17 California Code of Regulations;
  3. Sub-optimal driving performance of a sober driver;
  4. Breathalyzer errors;
  5. Dietary or medical conditions related to ketosis;
  6. No legal justification for the DUI traffic stop;
  7. Mouth alcohol;
  8. Rising blood alcohol;
  9. Lack of mental impairment;
  10. Police misconduct;
  11. Non-compliant sobriety checkpoint for DUI stop;
  12. Medical defenses, like acid reflux, hiatal hernia, or GERD;
  13. Failure to read Miranda right;
  14. Defendant was not driving;
  15. Radio frequency interference (RFI);
  16. Mistakes in field sobriety testing;
  17. BAC higher than the legal limit but the driver was not intoxicated;
  18. Other reasons for physical symptoms of intoxication;
  19. Universal variances in chemical testing results; and
  20. Significant difference between defendant’s BAC and impairment.

Your defense lawyer will perform an investigation to see whether any of these challenges or other defenses are available to you. The procedural aspects of these defenses will vary depending on the argument your DUI attorney wishes to raise. For example, one defense might be useful when negotiating with the prosecutor, while another challenge might lead to a motion to suppress evidence or a motion to dismiss the charges.

DUI Breath Test Errors

Four of the most common mistakes with DUI chemical testing that involves breath samples are:

  • Positive results caused by non-alcoholic substances, like breath sprays or mouthwash. Additionally, the breath of people with diabetes can contain acetones without the individual having consumed alcohol. These acetones can generate a false positive result on a chemical breath test. 
  • A person’s mouth can contain high levels of alcohol shortly after they consume an alcoholic beverage. Also, burping or vomiting can leave residual alcohol in the mouth. After drinking alcohol or having vomited or burped, the suspect should wait 15 minutes for the residual alcohol to subside before testing, to increase the reliability of the results.
  • Like any type of equipment, breath test devices must be checked regularly for accuracy. The sensors can malfunction with frequent use, resulting in higher readings without actual higher levels of BAC. Failure to calibrate the breathalyzer according to schedule can yield unreliable results.
  • Breathalyzers operate by using software. Every type of software can develop glitches and other reliability issues. In addition to catching hardware problems, regular calibration and maintenance of breath testing devices must be performed as per schedule to increase the likelihood of accurate results.

Your DUI lawyer can investigate to see if any of these errors were present. 

Mouth Alcohol as a DUI Defense

Sometimes, a person can test positive on a chemical analysis of their breath for BAC even if they did not drink any alcohol. Many people do not realize that breath freshening sprays or mouthwashes can contain alcohol. Some over-the-counter cold or cough medications contain alcohol, and even chewing tobacco might be treated with alcohol.

If you have dentures or retainers in your mouth, those dental appliances can harbor alcohol from food and beverages, and release the chemical during the breath test. Also, if you have a hiatal hernia, heartburn, acid reflux, or gastroesophageal reflux disease (GERD), your medical condition could artificially cause an elevated BAC reading on a breathalyzer test.

GERD, Acid Reflux and Hiatal Hernia: Medical DUI Defenses 

Unless you are underage, on probation for an alcohol-related offense, or have another extenuating circumstance, there is nothing illegal about driving after having had a small amount to drink as long as you are under the legal limit and not impaired by alcohol. Unfortunately, certain medical conditions can cause falsely high readings on a breathalyzer because these diseases “bounce” more alcohol particles back up the throat and into the mouth, where they get read by the breath testing device.

For a breathalyzer device to work correctly when measuring a person’s BAC, they must assess “deep lung air” as opposed to mouth alcohol. Breath testing equipment is not always sensitive enough to separate deep lung air BAC from mouth alcohol BAC, despite what some prosecutors argue.

Ketosis as a Result of Diabetes or Low-Carb Diets

People with diabetes might go through life in a frequent state of ketosis or ketoacidosis, which can cause DUI breath tests to render inaccurate readings. Without getting into the complicated chemistry behind this phenomenon, suffice it to say that the ketones a person can produce in their liver when they are experiencing ketosis can register as alcohol on a breathalyzer.

Although the ketones will be on the person’s breath and thus measured by a chemical breath test device, these substances are not actually intoxicating to the person. In fact, many people do not have any noticeable symptoms of ketosis.

Low carbohydrate, high protein diets are quite trendy now, and have been popular for years. Although some people find these diets to be effective for weight loss, they might not realize that they could fail a DUI breath test while on one of these weight loss regimens because the diets place the body into a state of ketosis. Breathalyzers cannot tell the difference between ketones from diabetes and ketones from a diet, much less whether the positive breath test result was from alcohol or ketones.

Auto-brewery Syndrome (Gut Fermentation)

A rare medical condition can cause a sufferer to become drunk even when they have not consumed alcohol. “Drunkenness disease,” also called endogenous ethanol fermentation, gut fermentation syndrome, or auto-brewery syndrome, is when your body creates its own alcohol from carbohydrates, according to HealthLine.

A person with this medical condition could have a blood alcohol level many times higher than the legal limit after eating starchy or sugary foods. A person with this disease can prove their condition through medical testing. The National Institutes of Health reports that fungi or bacteria in the individual’s body can create the appearance of alcohol intoxication. 

Breathalyzer Test Errors or Inaccuracies

A breathalyzer is a convenient and quick way to measure a person’s blood alcohol concentration (“BAC”), but it is not without errors. The device merely takes a “snapshot” of the chemicals in a person’s breath at the moment of testing. Many things can go wrong to cause an inaccurate BAC result.

For example, the device might not be in proper working order, or the officer who administered the test might not have followed the required protocols. Residual mouth alcohol from breath sprays or mouthwash could falsely trigger a positive result. Certain diets and medical conditions like diabetes or GERD can lead to an inflated BAC level or a false positive based on ketones instead of alcohol. Also, the phenomenon of rising blood alcohol can render an inaccurate chemical breath test outcome.

Rising Blood Alcohol as a DUI Defense

Rising blood alcohol can be a useful defense if your BAC is barely over the legal limit. When a person drinks alcoholic beverages, it takes time for the alcohol to affect the body, just like you do not get immediate relief the second that you swallow a pain pill.

A person’s BAC follows a bell-shaped arc, which rises, peaks, and then goes back down. If you are pulled over for suspicion of drunk driving shortly after consuming alcoholic beverages, and the officer does not perform the chemical breath test for a significant period of time, you might be able to raise the legal defense of rising blood alcohol.

In other words, the BAC level at the time that you blew into the breath test device was not the same as your BAC level when the officer pulled you over. If your BAC is substantially higher than the legal limit, however, this defense is likely to be unsuccessful. For a person whose breath test registers a BAC only slightly above the legal limit, though, one might argue that a breath test performed immediately would have shown a BAC that would not have violated California’s drunk driving laws.

DUI Blood Test Errors

Blood testing for DUI charges is not immune from the possibility of mistakes. Chain of custody is one of the more common defenses in these cases. The prosecution must be able to prove who had the blood sample in their possession at all points from the moment of drawing the blood sample, to running the test, and securing the evidence in the custody of law enforcement to prevent any mix-up of samples or contamination of the blood sample in question.

Sometimes, blood test results are inconclusive. Also, improper storage of the blood can call into question the accuracy of the alcohol or drug analysis.

Lack of Probable Cause for a DUI Stop

The police are not allowed to simply pull over anyone they wish to subject to a traffic stop or perform a DUI arrest without justification. When a person gets pulled over because of how they look, the kind of car they’re driving, or some other reason that does not involve reasonable suspicion for a traffic stop or probable cause for a DUI arrest, they might have grounds for dismissal of the charges. Failure to enforce this requirement of probable cause or reasonable suspicion would result in giving law enforcement officers the opportunity to engage in widespread harassment.

If the police pulled you over for a DUI stop without the required level of justification, your attorney could file a motion to suppress any evidence the officer obtained. If the judge grants this motion, the outcome could be a gutting of the evidence supporting the charges against you, resulting in a not guilty verdict or a dismissal of the DUI case.

Arresting Officer Didn’t Read Miranda Rights

Thanks in part to inaccurate portrayals on television crime dramas, many people have a skewed understanding of Miranda rights. When a person is in custody, the police are not supposed to perform an interrogation until after they’ve read the individual their Miranda rights. At the moment the police perform the arrest, they do not have to “Mirandize” the suspect unless they plan to start the questioning right away.

You are receiving a recitation of your Miranda rights when the officer informs you that you have the right to remain silent, that you have the right to have a lawyer present when you are questioned and that if you cannot afford a lawyer, you might be able to receive an appointed lawyer, and that if you choose to say anything, it can be used against you in court.

Your criminal defense attorney will evaluate whether you were in custody or not. If a reasonable person would feel that they were not free to leave, the situation will likely be determined as custodial. Asking questions beyond a person’s name and other non-incriminating information is usually considered interrogation.

Innocent Explanations for Physical Signs of DUI

Police officers look for physical symptoms of intoxication when they pull over a suspect for drunk driving. If you have slurred speech, your face is red, you have watery or red eyes, your gait is unsteady, or they smell alcohol on your breath, those indications will likely be noted by the officer as physical signs of driving while under the influence of alcohol.

Of course, many other things can cause those symptoms, entirely unrelated to the presence or consumption of alcohol. For example:

  • You could have red or watery eyes because of allergies or a common cold.
  • Your walking gait could be perceived as unsteady because of a neuromuscular disease, a past back or leg injury, a history of stroke, or some other medical condition.
  • Your face could be flushed because of high temperatures, sunburn, a food allergy, or simple embarrassment about getting pulled over.
  • Slurred speech could be the result of a past stroke or mini-strokes, Parkinson’s disease, a past head injury that damaged the cranial nerves, or a host of other medical causes.
  • You might have an odor of alcohol on your breath after consuming low-alcohol beer or wine, or having consumed a small amount of alcohol and burping shortly before the officer smelled your breath. 

Inaccuracy of Field Sobriety Tests

People can fail field sobriety tests because of factors unrelated to alcohol, like sleep deprivation from having a sick child at home, confusion due to advanced age, gross motor skill disabilities, or misunderstanding instructions due to language differences or hearing loss. 

No matter how objective one might try to make the parameters of field sobriety testing, there will always be a component of subjectivity on the part of the officer. What one officer might consider as significant impairment, another might view as slight or no impairment.

Simple Bad Driving–Not DUI

Most collisions involve poor decision-making and questionable driving skills, rather than the use of alcohol or drugs. A person might not notice another vehicle or that the light has changed because they are distracted or exhausted. Many people have their minds on other matters when they’re behind the wheel. Sometimes, a police officer might interpret simple bad driving as driving under the influence of drugs or alcohol.

BAC Over the Legal Limit Not the Same as DUI

DUI, driving under the influence of alcohol, is not the same thing as having a blood alcohol concentration (BAC) that exceeds the legal limit. When a person drives under the influence of alcohol, that means that they experienced impairment that affected their mental or physical ability to drive safely. A person might have a BAC over the legal limit but be perfectly capable of operating a motor vehicle in a safe manner.

Inherent Error Rates for DUI Chemical Testing

Every device has a margin of error. For this reason, specifications for equipment often include a range of errors that one can expect when using the device. For example, a thermometer, when functioning correctly, might have an accuracy rate of +/- 0.01 degrees Fahrenheit. When properly calibrated and maintained, the thermometer can reliably measure the temperature to within 0.01 degrees above or below the actual temperature.

Equipment used in DUI chemical testing is no different. All of these devices have a margin of error. When you have a chemical breath test, blood test, or urine test, the equipment used will not always generate a result that is precise. If your BAC is borderline, the inherent error rates for DUI chemical testing could be the defense that saves you from a conviction.

DUI Sobriety Checkpoint Not in Compliance with the Law

The police are fond of using DUI sobriety checkpoints to try to catch large numbers of drunk drivers, particularly during the holidays. For people trying to drive from point A to point B, however, these checkpoints can be a great inconvenience.

To prevent law enforcement from using sobriety checkpoints to harass people, the California state legislature has enacted regulations that must be followed. If the police make a mistake in following these rules when setting up a DUI checkpoint, your DUI defense attorney might be able to file a motion to suppress evidence or a motion to dismiss the DUI charges. An administrative, supervising officer who will not be at the scene must make all the operational decisions about the setup of the checkpoint to prevent constitutional violations.

The operational decisions must include a neutral process, chosen beforehand, for determining which vehicles will get stopped. For example, the officers will stop every fourth car or every 10th car at the checkpoint.

Radio Frequency Interference (RFI) as a DUI Defense

The United States Department of Justice, Office of Justice Programs (OJP), has acknowledged for the last 40 years that radio frequency interference (RFI) can cause inaccurate test results on breathalyzers. Although some of the chemical breath test device technology has improved during that time, the problem of RFI has not been entirely eliminated.

BAC Doesn’t Accurately Reflect Impairment

This situation arises when a person’s BAC is higher than one might expect because they do not appear to have alcohol impairment. Medical conditions, weight, gender, age, and other factors can cause a person’s BAC to be elevated. California DUI attorneys could argue this defense on your behalf.

Police Misconduct in DUI Cases

If the arresting officer made a mistake or violated your constitutional rights, your defense lawyer could use that fact to keep some or all of the evidence out of court, negotiate lesser charges, or seek a dismissal of the criminal case. 

Police misconduct can include things like not having a valid reason for the traffic stop, making an improper arrest, mistakes in performing the breathalyzer test or field sobriety test, errors in administering blood testing or urine testing, violation of your constitutional rights, and lying in an affidavit or at court.

How to Get Out of a DUI or DWI?

The methods one might use to try to get out of a DUI or DWI will be highly individualized. A California DUI lawyer can evaluate your case and determine the best strategy to challenge the charges and try to get out of the DUI or DWI.

How to Fight a DUI Charge?

Fighting a DUI charge might involve your DUI defense attorneys attacking the chemical testing results, procedural violations of the traffic stop or arrest, or seeking to suppress the prosecutor’s evidence.

Is It Worth Getting a Dui Lawyer in California?

Sometimes, people hesitate about getting a DUI defense lawyer in Los Angeles because they are afraid of the expense. In reality, if you try to fight DUI charges by yourself and fail, the financial impact on your life can be significantly greater than the legal fees you would have paid to a California DUI lawyer.

Also, having an alcohol-related offense on your criminal record can cost you your job, your professional license, your freedom, your ability to transport yourself in a motor vehicle, and many additional adverse consequences. California DUI attorneys can help to fight DUI charges and protect your rights. Speak to one of our DUI Defense attorneys today by reaching out to us here.


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