While DUI stops are legal, law enforcement officers must use specific procedures that protect your rights. If there is a mistake in the initial stop, the test, or evidence handling, your case can be compromised. Your first line of defense is proving these potential errors. An experienced DUI Attorney can create a strong defense and challenge procedural errors, potentially leading to decreased charges or dismissals. This guide shows how common police mistakes at DUI stops could help strengthen your defense.
If you are dealing with a DUI matter, contact the San Diego DUI Attorney. We will make sure the police are held accountable while we build a strong defense strategy.
Stopping You Without Probable Cause
Under the Fourth Amendment and California Penal Code 836(a), it is unlawful for police officers to stop a driver without probable cause or reasonable suspicion. The police require probable cause to make an arrest. An officer has probable cause when he/she has a reasonable belief based on the fact that the driver committed a crime.
For example, a police officer may find probable cause based on:
- Observed speeding, which is a violation of Vehicle Code 22350
- Running a red light, a crime under Vehicle Code 21453
- Unsafe lane changes, a violation of Vehicle Code 21658
Your detainment, also called a Terry stop, can be legal if the officer has specific facts, giving them reasonable suspicion that you are engaged in criminal activity. If these legal standards are not met, your stop is illegal. An anonymous tip without proof or evidence is not enough to validate your stop, as held in People v. Wells, 2006.
Law enforcement can pull a driver over for a vehicle equipment violation. However, if the evidence suggests the stop was pretextual (based on profiling), your lawyer can challenge the validity.
Illegal stops can lead to suppressed evidence. Your attorney could file a motion to suppress, and if the judge grants it, the judge will exclude evidence like breathalyzer results, which will help your case.
Police Failing to Read The Miranda Rights to the Driver
Violating your right to a Miranda warning can significantly impact the outcome of your DUI case. The Miranda v. Arizona case, which was decided in 1966, ruled that police officers should inform the arrestee of their right to remain silent and to have an attorney present during interrogation. During custodial interrogations, officers have to provide Miranda warnings advising that you have the right to remain silent, your statements can be used against you, and you have a right to counsel. This happens when you are in custody, are not free to leave, and are being interrogated to elicit incriminating responses.
These common Miranda violations occur in DUI cases when officers question you after a DUI arrest without providing these warnings. For instance, if you are in cuffs and are asked, “How much did you drink?” before being Mirandized, this amounts to an illegal interrogation. Similarly, if you have been detained for a long enough time on the roadside in a custodial manner where you are questioned about drinking and given no Miranda warnings, your statements can be suppressed. An attorney can file a motion to suppress any incriminating statements made before you were Mirandized. Courts often grant these motions if the prosecution does not prove you were adequately apprised of your rights.
Invoking your Miranda rights is crucial. Police officers should stop questioning if you clearly state, “I want to remain silent” or “I want my attorney.” After this, if the officers keep talking to you, those statements are coercive and will not be used against you. You need to assert these rights. Mumbling or silence does not count.
It is important to distinguish between detention and arrest. Brief detentions like those during sobriety tests do not trigger Miranda unless they go on too long and make you feel like you are being arrested. Arrest, marked by handcuffs and booking, does. For example, If you voluntarily admit to drinking before being read your Miranda rights, your statement could still be allowed unless they obtained it during a direct interrogation. A DUI defense lawyer can motion to exclude this statement.
Field Sobriety and Breath Tests Done Without Probable Cause
If you have been given a DUI test, field sobriety test (FST), or breath test without probable cause, this can undermine the state’s case against you. Police must have particular facts to arrest somebody for DUI under the Fourth Amendment. A DUI test may not be justified due to a mere traffic infraction like a broken tail light or speeding. As a result, the lack of a probable cause is a key defense point. Without it, the test is invalid.
A traffic violation will not create probable cause for a DUI arrest, though if the officer sees other signs of impairment, they could investigate further. Officers must see signs of impairment, such as:
- Slurred speech
- Strong alcohol odor
- Bloodshot eyes
- Erratic behavior like excessive swerving
- Difficulty following instructions
If the officer observes these signs of impairment, plus a traffic violation, this could be enough for probable cause for an FST or preliminary alcohol screening (PAS) breath test. Nevertheless, it is important to point out that a hunch based solely on a minor traffic violation without any discernible signs of impairment is insufficient. Courts have repeatedly held that a traffic violation alone does not authorize testing for a DUI but must be backed by other evidence of impairment.
Due to this, you could contest a DUI test done without probable cause in court. If an officer asks you to take a field sobriety test (FST) or a preliminary alcohol screening (PAS) and there are no clear signs of impairment other than a minor traffic violation, you can talk to your attorney about disputing the validity of the test. Results from these tests, for example, failing an FST or blowing high on a PAS, can be excluded. This will significantly weaken the prosecutor’s case.
If an officer requests an FST or PAS under these circumstances and you believe the request is unwarranted, you can assert your rights. In California, a non-commercial driver over the age of 21 is allowed to refuse the pre-arrest sobriety test and preliminary alcohol screening test. No penalty will be incurred. You can politely refuse these tests by saying, “I do not consent to this test.” Your refusal will not have any legal consequences as these tests differ from evidentiary tests, blood or breath, that you may be requested to take if you are arrested. The PAS is a pre-arrest test. Once you are at the station, the evidence test is the official record. Refusing a PAS could irritate the officer, but they cannot force you to take it without probable cause. In contrast, refusing a test after an arrest can land you in serious trouble. You could be fined, jailed, and have your license taken away due to implied consent laws under CVC 23612.
The Differences Between Breath and Blood Tests in California DUI Cases
After being arrested for DUI, you could face a breath or blood test to confirm the DUI. Both choices have their pros and cons, which can significantly influence your blood alcohol readings and your defense against DUI.
In particular, breath tests are fast and non-invasive. They provide a blood alcohol content reading based on a partition ratio, a 2,100:1 conversion of breath alcohol to blood alcohol. Breath tests are convenient, but they give an estimate, not a measurement. Illness, including emphysema or asthma, can affect results since weak lungs may not be able to deliver a deep sample or acetone from ketosis could falsely increase the BAC. Mouth alcohol contamination and calibration variation also cause significant errors. Breath tests are especially prone to inaccuracies if there are difficulties breathing or a recent meal.
Blood tests are done directly on the veins for blood alcohol content. So, there is no guesswork with partition ratios. Blood tests could be precise and less influenced by the environment, but they can be invasive, take longer to yield results and might stress out people afraid of needles. Blood tests are the gold standard, but improper handling, like storage and contamination, can create unreliable results. For healthy users with no fear of needles, blood tests usually provide a better measure.
As a result, whether you will have a blood or breath test depends on your situation. A blood test prevents the fumes from affecting the accuracy of a breath test if you have emphysema or asthma. If needles scare you, then a breath test saves you from the ordeal but may give you less accurate results. After being arrested, you can choose unless you refuse both. If you do, you will face the penalties of implied consent. Choose the option that is best suited for your health and case.
Moreover, blood tests have a significant advantage due to their ability to preserve a blood sample for retesting. After the draw, an officer must keep a split sample per Title 17. Your lawyer can act quickly after the arrest and:
- Request for the blood sample through a discovery motion
- Obtain the sample, chain-of-custody records and lab reports from the DA or police
- Send the sample to a private lab to ensure BAC is accurate and check for contamination and fermentation
A lower reading or an error strengthens your DUI defense. Breath tests, on the other hand, do not allow for retesting. Once the test is administered, the result is permanent. Do not also forget to share your health history with your lawyer.
Do You Have To Take a Chemical Test?
If you refuse a chemical test after a DUI arrest in California, you will face harsh penalties due to the implied consent law, Vehicle Code 23612. When you obtain a driver’s license you consent to take a chemical test, blood, breath, or urine, if arrested for DUI. Declining this test after an arrest is not just skipping it. This decision leads to increased penalties, DMV license suspension, and a more challenging legal fight. Knowing the consequences of refusing a DUI test is crucial for your defense.
To clarify the distinction, the preliminary alcohol screening (PAS) or roadside breath test is optional pre-arrest. Police officers must have probable cause even if you refuse to offer a test sample to arrest you. However, the situation changes drastically post-arrest. If you decline to submit to the breath or blood test at the station, you violate implied consent.
If you refuse the test:
- The DMV will automatically suspend your license for one year on a first offense, two years if you have a DUI on your record and three years on other refusals
- You could spend an additional 48 hours and $500 in fines
- A second time causes a 10-day bare minimum in jail, while a third is 18 days.
The officer’s sworn report initiates an administrative action, separate from court, that is unlike a DUI conviction.
Prosecutors could argue that the refusal shows “consciousness of guilt,” although that can be contested. If you face DUI charges, the burden of proof shifts to you to prove that you were sober. The DMV hearing, your chance to challenge the suspension, is largely based on the officer’s testimony unless you have compelling evidence, for example, a video of coerced refusal.
Strategically, refusing a chemical test could be justifiable in a few circumstances. If you are confident that your BAC will be extraordinarily high, for example, 0.20%, and a medical condition, like asthma, is preventing you from giving a breath sample, then forcing a blood draw will buy you time while also offering up an opportunity for you to demonstrate a procedural error. On the other hand, refusing could help avoid incriminating evidence, if the arrest itself is questionable. However, you will still face enhanced penalties. However, this is still a big gamble. You should consult an attorney immediately.
In the end, be forthcoming with your lawyer. Let them know why you refused. The aftermath of refusing a chemical test can be serious, but a strong argument against the DUI arrest can mitigate the impact if there is a problem with the stop or arrest.
False Interpretations of Field Sobriety Tests
Field sobriety test errors often undermine DUI charges. The tests produce unreliable results, proving unsuitable for evidentiary purposes. Field sobriety tests (FSTs) like walk-and-turn and one-leg stand are subjective and rely too much on an officer’s judgment. FST results are often subject to errors, and that makes a strong basis for challenging them in your DUI defense.
Moreover, FSTs are often affected by factors that have nothing to do with intoxication. For instance, poor lighting could prevent an officer from making proper observations, thus leading to misrepresentations of their observations. The uneven surfaces, like cracks in pavements or graves, can also cause coordination problems in sober people. Medical issues like inner ear dysfunction, arthritis, or neuropathy can produce similar effects. Age and weight can also significantly affect performance. So, these many variables create a lot of uncertainty, but officers attribute them to DUI without further investigation. Thus, the scientific validity of FSTs is doubtful.
A DUI lawyer can challenge FST results based on these faults. It is possible to explain failing the test due to uneven ground, a medical condition, or darkness. An FST may not be admissible in court if the officer rushed you during the instructions, denied you help, or failed to follow NHTSA protocol. NHTSA standards should be followed strictly for set-up and directions to the suspect. Any deviation, for example, failing to perform the “walk and turn” or testing on an uneven surface, will render the FST inadmissible.
Misleading Positive Results From the Breath Tests
DUI charges based on a single breath test are grave. However, what you may not know is that breathalyzer false positives exist. Police officers use breath tests to determine whether a driver has been drinking, but they are not infallible. Many people are charged for drunk driving simply because of a false positive.
Breath testing has limitations that result in errors and problems. Breathalyzers estimate a person’s BAC using a partition ratio of 2,100:1 breath-to-blood alcohol, which is an average and not necessarily universally accurate. Individual variations can skew results. Furthermore, breath tests can be contaminated, where residual alcohol, burps, and reflux can exaggerate the results. Health issues like diabetes, acid reflux, and low-carb diets produce acetone, which some devices misinterpret as alcohol. Moreover, external factors like mouthwash or cough syrup can interfere with the sensor. Officer error, including poorly calibrated devices or skipped observation periods, exacerbates these issues, creating a high risk of false positives.
As a result, people are arrested and prosecuted based on these results. District attorneys depend on these results, and without a strong defense, convictions are likely.
With the right strategy, your attorney can challenge these inaccuracies. Your lawyer may be able to contest the breath test results based on your medical condition and request calibration and maintenance records or videos that could challenge the results.
If it is successful, this can lead to the evidence being thrown out, which could potentially collapse the case. Consequently, you should know that false positives happen often and are not unique to your case. Therefore, when engaging a DUI attorney, provide comprehensive details about your food, medications, and what you have eaten recently.
Procedural Errors in Breath Test Administration
If the proper procedure to administer a breath test is not followed, it can result in false positives and an innocent person facing DUI charges. This is an excellent basis for fighting DUI charges.
According to Title 17 of the California Code of Regulations, breath tests must comply with strict breath test regulations. As a result, failure to follow procedures, like improper breath test administration, can lead to erroneous breath test results and falsely elevate your BAC and thus lead to DUI charges.
The regulations specify that a trained officer must use an appropriately calibrated and approved device, typically an intoxilyzer, within the acceptable parameters of 10 days of calibration or 150 uses (breath test calibration). The officer must conduct a complete 15-minute observation period to ensure you do not eat, drink, smoke, or vomit. The test should give a deep lung sample, with the two blows taken minutes apart, and the record kept very carefully. If the officer fails to observe the waiting period, uses a malfunctioning device, or accepts an insufficient sample, the test results could be doubtful. Due to these procedural errors, your BAC can be elevated above the legal limit.
A faulty breath test often causes a DUI arrest, which leads to fines, jail time, and license suspension. Nonetheless, this failure to follow procedure is a great defense. If the officer fails to follow the procedures, your lawyer can argue that the breath test results are invalid. In the past, courts have dismissed evidence for procedural violations similar to this, such as in the case of the People v. Adams, 1976, and the case often collapses without valid BAC evidence.
To successfully fight the breath test, compare your experience to the proper protocols, that is:
- Was the observation period rushed?
- Did the officer struggle with the device?
Your attorney will request calibration logs and training records of the breath test through discovery. Video evidence of a burp during the waiting time or an inconsistent second sample can help you. Therefore, tell your lawyer everything that may be relevant. For example, “They tested me too quickly,” or “The machine was making strange noises.” Errors in the breath test procedure are not just technicalities. Critical errors can be used against the case, which can have the DUI charges dismissed.
Find a DUI Attorney Near Me
Even a single error in your DUI case can be pivotal. An experienced DUI lawyer can find procedural errors and formulate a strong defense. They can identify mistakes made during the case that could lead to its dismissal. At San Diego DUI Attorney, we are here to help defend you if you are facing DUI charges. Contact us at 619-535-7150 for assistance.
