Skip to main content

What requirements must the government meet to convict a person of a DUI?

In order for the government to establish a DUI case against you the district attorney must meet all elements of a California Driving Under the Influence case. One of these is that the government must prove that you were driving while you had a Blood Alcohol Level (BAC) significant enough to warrant arrest. There are many different ways the prosecutor can prove driving, some situations more complicated and more difficult to prove than others.

The first, and the easiest is if the police had a valid reason to pull you over in the first place?

There are several situations in you may be lawfully pulled over and questioned in regards to a DUI. The arresting officer may pull you over for any vehicle code violation whether it is related to alcohol impairment or not. Alternatively the stop does not even need to be directly tied to driving at all. If the police officer can articulate probable cause (that any crime was committed and that you likely committed it) then they can make the stop to further investigate. The key however, is whether or not the Police Officer can sufficiently "articulate" the reason for the stop.

If the police officer can articulate the stop then there will be sufficient probable cause for the officer to further investigate whether or not you may have committed a DUI. This may seem like a simple task to accomplish but in truth this stage is where the government’s case is most susceptible to a dismissal.

It is always the primary goal of Core Law Group’s DUI defense attorneys to immediately investigate whether the initial stop was valid. If it was not, and often it is not, then any evidence obtained by the officer from that point on can be argued as inadmissible and result in a dismissal of your case. However, it takes a trained eye and knowledge of the vehicle and penal code to identify errors made by the arresting officer at the initial stage. It is always in the best interest of our clients to weaken the government’s case against you at you in the beginning when it is most vulnerable.

The second requirement is if the officer has sufficient probable cause to investigate whether you were driving under the influence of alcohol or another substance?

Once an individual is pulled over for a DUI, nine times out of ten, they are asked by the police officer if they have had anything to drink? Every police officer is trained to do this. The reason being is that an answer in the affirmative automatically gives them the probable cause necessary to move on to the next stage of the investigation. This is when individuals should stay silent. However, experience shows us that almost all of our client by nature are honest and tell the officer they have had something to drink. Once you tell the officer that you have had any measurable amount of alcohol to drink they can automatically continue to observe (and test) you to determine if you are driving under the influence of alcohol.

However, if an individual does not admit to having consumed alcohol then the officer has to take the additional step of using their skill, knowledge, training and experience to determine if the objective signs of impairment are visible. Again they must be able to articulate these facts. Was there an odor of alcohol? Were the driver’s eyes red or glossy? Did the driver fail to follow basic directions? It is more difficult for the officer to have to articulate these facts. Therefore, it is best that an individual does not volunteer or admit they have consumed alcohol. Let the officer meet their burden without the aid of the driver.

Here too, the criminal defense attorney’s at Core Law Group are trained to determine if the officer followed protocol and was sufficiently able to articulate the reasons he suspected an individual was driving under the influence. It is the goal of our DUI defense team to poke holes in the officer’s argument. If done properly our Orange County and Los Angeles County DUI attorneys can prevent the government’s case from progressing forward and obtain a dismissal on your behalf.

The third requirement is if the Arresting Officer’s investigation resulted in sufficient probable cause to believe you may be driving under the influence?

This is normally the stage where the officer asks a driver to step out of the vehicle and perform multiple field sobriety tests. However, there is no law that states that an officer must cause the driver to perform the FST’s. The law only states that an officer must observe the driver for 15 minutes prior to making the determination as to whether or not they suspect the individual was driving under the influence of alcohol. The officer has the option to simply observe an individual while they sit on the side walk for fifteen minutes before they make their determination. Of course, taking this route makes it more difficult for the police officer to articulate as to why they believe the driver was under the influence.

To ease their burden the police agencies have instituted as part of their protocol various field sobriety tests. Through these tests they can document why they believe an individual was driving while impaired. However, these tests are not perfect and there are many specific requirements the police officer must meet while documenting the results of the test. Were the instructions properly given? Was there an ample demonstration? Was enough time given to perform the tests? Did the length of the tests surpass fifteen minutes? These are only a few of the types of questions that must be asked when determining whether the FST’s were administered properly. If they were not, the arresting officer may lack the probable cause necessary to make the arrest and the Core Law Group DUI Defense team can obtain a dismissal of your case.

Of course, the police agencies have found a way to ease their burden at this stage of the investigation as well. Over the last decade just about every agency in California has begun utilizing Preliminary Alcohol Screening Test Devices (PAST) as a means to strengthen the probable cause for the arrest; this is when the officer offers the driver a breathalyzer on the field (at the scene of the investigation). The Police Officer’s know that most individuals mistakenly believe they have to consent to this test and they use it to their advantage. The reality is that this on the field breathalyzer (prior to the arrest – being handcuffed) is voluntary and an individual does not need to consent to taking it.

If an individual agrees (most do,) and the results are over the legal limit then the officer has easily met their burden of articulating why the individual should be arrested for suspicion of driving under the influence. However, once again the officer’s arrest at this stage is not fool proof. California law requires the arresting officer to give a very specific admonition to the driver stating that the PAST test is voluntary. If the officer fails to do so or if the officer does not do so properly, our trained, DUI defense attorneys, can attack the probable cause the officer stated for the arrest and obtain a dismissal.

Finally, there must be sufficient proof a mandatory chemical test that provides probable cause for the arrest.

California Law requires a driver must agree to a chemical test (either a breath test or blood test) after they have been arrested. A refusal results in automatic suspension of an individual’s driving privileges and sentencing enhancements at the criminal case. This mandatory chemical test (unlike the PAST test above) is given at a police station or sub-station and the driver is given the election of which test to take. If a breath test is elected, a breathalyzer is administered to record the individual’s blood alcohol level. If a blood test is elected then a sample of the individual’s blood is taken for further testing by the police laboratory. Once again, neither test if fool proof. An experienced DUI attorney at Core Law Group can attack the sufficiency of either test by establishing the strict requirements of the tests were not met. For example: was the breathalyzer used calibrated or cleaned properly? Was the blood taken by a licensed phlebotomist? Was the blood sample adequately retained meeting the requirements of chain of custody?

In summation, there are many defenses that need to be explored at the various stages of a DUI arrest. It takes a trained DUI attorney to identify those defenses. It is important to have a professional lawyer explore the defenses available and defend you at a DUI. There is simply too much too lose, not just a driver’s license, but also a criminal record is at stake.

Additional resources provided by the author

To learn more about DUI’s visit Core Law group’s blog at or call one of our attorneys at 888-652-5529.

Rate this guide

Avvo DUI email series

Sign up to receive a 3-part series of useful information and legal advice about DUIs.

Recommended articles about DUI

Can’t find what you’re looking for?

Post a free question on our public forum.

Ask a Question

- or -

Search for lawyers by reviews and ratings.

Find a Lawyer