Common Policing Errors For A DUI Stop

Stopping A Motorist Without Probable Cause

Police officers are required to have “sufficient probable cause” before making a traffic stop (California Penal Code Section 836a). If these criteria were not met in your traffic stop, it may have been an illegal stop, and your case could be dismissed. 

Put simply, the police must have a legitimate reason to stop your vehicle.  Keep in mind, that just to make the initial stop, they do not necessarily need probable cause that you are driving under the influence.  Reasonable suspicion that you are in violation of any traffic law is enough to be stopped; being pulled over for rolling a stop sign is a common example.  Even so, if you can prove that you actually did make a full stop at the sign, the traffic stop will likely be found invalid.  Our attorneys know exactly what to look for when determining whether your initial traffic stop was lawful.  If we are able to show the stop was invalid, any evidence gathered as a result of the stop comes in to question, and will likely be suppressed.

Issuing A Field Sobriety Test Or Breath Test Without Probable Cause

In addition to having a reason to stop your vehicle, the police also need a reason to conduct a DUI test.  Staying with the example used above, rolling a stop sign does not necessarily suggest that a driver is intoxicated.  In fact, most traffic violations alone, should not suggest that the driver is intoxicated. Typically, what will happen is that the police will observe some symptoms or signs that suggest you are intoxicated after you are already stopped.  Slurred speech, the smell of alcohol, or bloodshot eyes are often cited as signs of intoxication.  The attorneys at the San Diego DUI know when a DUI test is appropriate and when a test is issued without cause.  As noted above, evidence of your intoxication is not always admissible.  There are a number of laws and procedures the police must follow when gathering evidence against you.  Remember, if a DUI test should not have been issued, the results should not be used against you.

Failure To Read The Miranda Rights

In some cases, drivers make incriminating statements against themselves or even admit to driving under the influence.  If you have made such a statement, you might assume that the case against you is too strong.  However, depending on how and when the police questioned you, your statements may not be admissible.

Once you have been arrested, it is your constitutional right to have your Miranda Rights read to you by the arresting officer. These rights include your right to remain silent, your right to hire an attorney, and your right to have a public defender assigned to you if you cannot afford an attorney. If the arresting officer failed to read the Miranda Rights to you, any information that you divulged after the arrest becomes inadmissible as evidence against you.  Further, even if you were read your Miranda Rights, if you made it known that you wished to remain silent, or wished to have your attorney present, any police interrogation should have stopped.  If the police continued to question you after you invoked your Miranda Rights, we can fight to suppress any incriminating statements.  

False Interpretations Of Field Sobriety Tests

Field Sobriety Tests (FST) are used by arresting officers to determine your level of impairment if you are suspected of a DUI. These tests are intended to evaluate your balance, coordination and motor skills. The judgment of the officer administering the tests will determine whether you pass or fail. There are many factors that can contribute to errors in administering the FST. 

Some examples are:

1. Dim lighting.
2. A slippery walking surface. 
3. Poorly worded instructions from the officer. 
4. Error in the officer’s assessment of your coordination.
5. Unknown medical conditions at the time of testing.

False Positives In The Breath Test

Although California regulates breath tests, there are instances and errors that can lead to a "false positive". If your breath result shows a blood alcohol level greater than California legal limit, this could be due to several things. It is important to have a skilled attorney explore false positives that could lead to your case being dismissed.

False positives can be due to:

1. Contamination of the breath sample.
2. Officer operation errors. Some mistakes that people administering a breath test can make are not checking that your mouth is empty before the test and not properly attaching the mouthpiece to the machine.
3. Poor record keeping. The person administering the test must observe and record you continuously for 15 minutes before administering the test and then record the time that each "blow" was made.
4. Improper calibration of the device.
5. Medical conditions unknown at the time of testing. Fasting, Hypoglycemia, high protein/low carbohydrate diets and diabetics have been known to trick breath tests. When someone is on a low carb diet, their body will burn its own fat and produce ketones. Ketones are converted into acetone and a breath test can confuse alcohol with acetone. Fasting also causes the body to produce acetone that can fool a breathalyzer. Diabetics emit ketones due to their condition, which are often mistaken by breathalyzers.
6. Residual Alcohol in the mouth can lead to a breath test reading a higher alcohol level than the person actually has in their system. If you recently drank cough syrup, gargled with mouthwash containing alcohol, or drank alcohol right before the test, your breath test could come back abnormally high. Residual alcohol can stay in the mouth for up to 20 minutes. 

Our lawyers will carefully scrutinize each aspect of the FST to ensure that it was administered fairly and we will determine whether extenuating circumstances may exist, calling into question the officer’s interpretation of the FST.

As previously mentioned, there is room for error with a California DUI breath test. You can decline a preliminary alcohol screening breath test (PAS) unless you are under 21 years of age, or are on probation from a previous DUI. It is uncommon for police officers to let you know that you do no have to take the PAS test. 

The PAS test is given roadside on a handheld breathalyzer. This test is given before the driver is arrested. After the driver is arrested, an evidentiary air test on the breathalyzer will also be given.  This evidentiary air test usually takes place at the police station or possibly a mobile police checkpoint.

Failure To Follow Procedure During The Breath Test Administration

There are certain rules that police must adhere to when administering DUI breath tests. Some of the rules are:

1. The person administering the DUI breath test must be trained properly.
2. Only a California–approved DUI breath test device may be used.
3. The person administering must continuously observe you for 15 minutes before they administer the test. During those 15 minutes, you cannot smoke, eat, drink, burp, or vomit.
4. The breath test device must be correctly calibrated. California law states that a breath testing device is calibrated after every 150 uses or every 10 days, whichever occurs first. 
5. The person administering must keep proper records during each stage of the breathalyzer calibration and test.
6. The person administering must take two breath tests and the results can vary no more than 0.02 g per 100 milliliters of blood alcohol. It is okay for the person to ask you to "blow" more than two times to get the correct breath samples. 
7. The person administering must get the breath sample from deep in your lungs.

If these procedures were not followed in your case, the validity of the test comes into question, and it may be suppressed. 

Do I Have To Take A Chemical Test?

As noted above, if you are stopped and arrested for a DUI, there will typically be two distinct tests.  The first is the PAS test which is the pre-arrest roadside breath test.  If you are over 21, and not on probation, you can refuse to take the PAS test.  Even if you refuse to take the test, you still might be arrested for a DUI.  If you are ultimately arrested, you then must take the "chemical test" if asked.  Often officers will ask you to take a chemical test if they suspect you are under the influence of drugs, as well as, or rather than alcohol.

If you refuse to take a chemical test after you are arrested, it can result in enhanced penalties if you are convicted of a DUI.  Further, the DMV will suspend your license for a minimum of one year. 

Breath Test Vs. Blood Test

People often ask whether it is better to choose a blood test or DUI breath test? Unfortunately, there is no clear cut answer.  Both tests can work to your advantage or disadvantage depending on the specific case.

A DUI breath test will not measure your blood alcohol directly. The breath test mathematically converts the alcohol in your breath into the amount in your blood, which is why the sample must be taken from deep in your lungs. This conversion is called a 'partition ratio". 

Breath samples cannot be preserved, so it is difficult to verify the test at a later time. This can work to your benefit if an attorney questions the accuracy of the test.  On the other hand, blood tests can be preserved, and can be independently tested to verify the results.  This can also work to you benefit if the results show that test was not accurate.  

Keep in mind, there are certain medical conditions that may prevent you from taking a breath test.  Some of those conditions are emphysema, asthma unconsciousness.  Alternatively, fear of needles often makes the breath test more desirable. 

If you have been charged with a DUI, our attorneys can help you. Call us for a free consultation and we can begin to discreetly and respectfully investigate your case. Our attorneys are specifically trained and exclusively handle these types of cases throughout San Diego county.

The experienced criminal defense attorneys at the San Diego DUI Attorney can assess your case, build a strong defense, help reduce charges, and work to avoid a conviction following your DUI arrest. The entire staff at San Diego DUI proudly serves clients in Orange County, San Diego, Vista, El Cajon, Oceanside, Chula Vista and all other other San Diego County communities.

Contact Our Office Today At 619-535-7150 For A Free Dui Consultation.