Law Office of

​David Dastrup


DUI Defense

Traffic-Crimes Defense

Criminal Defense

Pre-Arrest PAS Breathalyzer

After a traffic stop or traffic accident response, a police officer that is reasonably suspicious of a DUI can detain a driver for a brief DUI investigation. The driver is not free to leave but is not yet arrested. The police officer will want the driver to do a roadside breath test. This usually occurs after a series of field sobriety tests, called "FST's." The pre-arrest blood alcohol test is called a “preliminary alcohol screening," or “PAS” for short.

A PAS is usually done with a handheld breathalyzer device on the side of the road. The device is used to read the alcohol gas content from the driver’s breath to calculate and display the “blood alcohol content,” or “BAC," of the driver.

Submitting to a PAS breathalyzer is voluntary. The driver does not have to do it. However, police tend to be forceful and convincing. For example, an officer may tell the detained driver that they will let them go if the driver can show a result of under 0.08% BAC, blood alcohol content, by using the breathalyzer.

In reality, most officers are simply trying to collect more evidence to justify an arrest. By the time a police officer asks for a breath sample, they have usually already decided to arrest the driver. However, it is worth noting that sometimes a low BAC from a PAS will actually result in the driver not being arrested. Regardless, a PAS is not required for a police officer to make a DUI arrest. 


Post-Arrest Chemical Test

After a driver is arrested, the test to determine the driver's blood alcohol level is called a “chemical test.” Taking a chemical test is mandatory under “implied consent” laws. If a DUI-arrestee refuses to take a chemical test, then the DMV will suspend their license for one year (with no restricted license).

The most common way to administer a chemical test is to take the arrested driver to the police station and use the station's breathalyzer device. This is because the chemical test must be done with a device that is maintained, regularly tested, and in proper working order at the time of the chemical test. In addition, the officer needs to be able to testify as to having been specifically trained and certified to use that specific device.

However, the chemical test may be done on the roadside with the same device used for a PAS, even a handheld breathalyzer, although this is unlikely. Regardless, for example, some police in the City of Orange, California, are certified to use a handheld roadside DUI breathalyzer for the chemical test. It looks the same as the PAS device but is held to stricter standards of use. (These DUI cases are heard at Central Justice Center in Santa Ana, County of Orange, California. The associated APS Hearing for the order of suspension of the driver's license is heard at the Orange Driver Safety Office of the California Department of Motor Vehicles.) 

The chemical test can also be an actual blood or urine sample. Urine samples are more common in drug cases. Police will usually only offer breath or blood to a DUI arrestee, not urine. Blood samples are very common for alcohol DUIs when there is a car accident and the driver is taken to the hospital. Regardless, blood draws are very common, for example, Torrance Police take DUI arrestees to Torrance Memorial Hospital. (These cases are heard at the Torrance Courthouse of the Los Angeles Superior Court; and at the El Segundo Driver Safety Office of the CA DMV.)

It is worth noting that if someone is arrested for a DUI and refuses to take a chemical test of any kind, even to not take the chemical test that is available, then, the police may get a warrant to force a blood draw against the driver's will. Sometimes, the police are unable to get a warrant for a number of reasons. Regardless, the lack of a specific blood alcohol level does not stop a DUI case from moving forward. Furthermore, the refusal allegation will be used against the driver in criminal court and at the DMV. Moreover, if a warrant was granted and a forced blood draw produced results of .08% BAC or higher, then the prosecution has more allegations for the criminal case and the DMV has a basis for the refusal or .08% BAC. (Note that the DMV will pursue the refusal issue because it is considered more serious, and carries a harsher license suspension.) ​


At Court and the DMV

There are several ways to defend against a DUI chemical test. If the testing procedures were improper, or if the device was not maintained, the results are unreliable. If a police officer is not certified or fails to follow their training, the test cannot be relied upon. For a refusal to submit to a chemical test, if the officer failed to read the implied consent admonishment, the refusal allegation is not valid. If the driver has a medical condition or medication that could have interfered with the chemical test, that may be a defendable issue.

The person arrested has constitutional rights. Driving is not a constitutional protected right--it is literally called a driving "privilege." However, the driver is a person, and the person has constitutional rights while driving, during a DUI investigation, during the arrest, after the arrest, in court, and throughout the DUI case. If a person's constitutional rights are violated by police, there are remedies. For example, any police evidence obtained solely as a result of the police violating that person's constitutional rights will be suppressed, meaning it will not be admissible against the driver at the DMV or in court. For example, if the police conducted an unlawful search and seizure without a warrant, like a stop or detention without reasonable suspicion, or an arrest without probable cause, then the chemical test results that came from the violation will not be usable by the police, prosecution, or DMV.

Asserting defenses and constitutional rights can lead to a dismissal, negotiations for a more favorable plea bargain, or an acquittal. 





The jurisdiction for a criminal DUI case in court is separate from and handled differently than the jurisdiction for a DMV DUI APS suspension order from the DMV.

Which courthouse the case is filed in depends on where the DUI arrest occurred and which prosecutor is handling the case. This changes from county to county and city to city. In contrast, the APS Hearing is usually held where the DUI arrest occurred, but not always. There is no prosecutor for the APS Hearing. It is only the Department of Motor Vehicles that handles APS hearings at Driver Safety Branch Offices of the DMV throughout California. Both fronts must be fought because a DUI can result in two separate license suspensions, from Court and the DMV.

For example, for a DUI arrest by the City of Long Beach Police Department, the criminal case will be filed by the Prosecutor of the Long Beach City Attorney's Office in the Governor George Deukmejian Superior Court of California. This is a County of Los Angeles building that happens to be in the City of Long Beach. Because of its location, it is normally called the Long Beach Courthouse, although it also serves the surrounding areas. This includes Long Beach Harbor, the City of Los Angeles (e.g., San Pedro, Harbor Gateway, LA Harbor), the City of Signal Hill, LA County unincorporated areas, etc. The law enforcement agencies represented at the Long Beach Courthouse include Long Beach Police, Los Angeles Police Department "LAPD," Los Angeles County Sheriff "LASD," Signal Hill Police, LA Harbor Police, California Highway Patrol "CHP," etc.

However, right next to LA is the OC, which is a separate jurisdiction. For example, if a DUI arrest occurs in the City of Seal Beach or Huntington Beach, whether handled by CHP or that city's police department, it will be filed by the Orange County District Attorney's Office at the West Justice Center "WJC" in Westminster. The WJC is also a Superior Court of California but in the County of Orange. Any DUI in Orange County can be heard at any Superior Court in the County of Orange. 

In contrast, the APS Hearing about a driver's license suspension can be heard at any Driver Safety Branch in the State of California. This is because the DMV has administrative jurisdiction over driver licenses throughout the whole State of California. Due to population and demand, there are 4 DMV Driver Safety Offices in LA but only 1 in OC. These include El Segundo, Commerce, Van Nuys, Covina, and Orange.

Driver Safety branches take DUI APS hearings based on what station the arresting officer is based out of. The DMV maps out which Driver Safety branch handles the APS Hearing. For example, a Torrance Police DUI arrest will hold the APS hearing at the El Segundo Driver Safety Office, as will a Lomita Sheriff Station DUI arrest. But a Compton Sheriff Station DUI arrest will be heard at the Commerce Driver Safety Branch. Any DUI arrest by police based out of a station in OC will be heard at the Orange Driver Safety Branch--not due to jurisdiction, just because of the map. For example, we had an El Segundo APS Hearing that was transferred to an Orange Hearing Officer because the El Segundo branch was overbooked. Another time, we had a DUI in Los Angeles County but the APS Hearing was handled out of the Bakersfield Driver Safety Branch. This demonstrates that the DMV is the same throughout all of California (very different than the Superior Courts that are by county). 

Regardless, your attorney will navigate the DMV and Superior Court systems for you. 

Now is the time to start your legal defense.  


Being arrested is a shocking and frustrating experience. You are not alone. We defend you at court and the DMV.

Criminal charges for driving under the influence of alcohol usually start from a small situation. For example, most DUIs start with a traffic stop for a suspected minor infraction of the California Vehicle Code. If the traffic stop is in the evening, the police officer will ask the driver if they had any alcohol to drink, even if there is no initial indication of alcohol.

If a driver admits to drinking any alcohol, the officer will instruct the driver to step out of the vehicle. This is what is called a DUI detention. The detention is not an arrest, but it feels the same because you are not free to leave.

If the driver says they did not drink, the officer smells alcohol through the driver-side window, the officer will ask the driver to step out of the vehicle. Even if the driver states that they had nothing to drink because they are the designated driver for a passenger in the vehicle who did drink, the police will still detain the driver to start a DUI investigation. This detention is supposed to be brief. But it is always uncomfortable, whether from being interrogated by police or, if at night, from standing out in the cold when not dressed to be outside.

Once a person is up and walking, officers are deciding, if not already, that they are going to arrest the person for DUI. A Los Angeles County Sheriff's Deputy will watch for the slightest sway or unsteady gait, for bloodshot watery eyes or slurred speech. One of the most important indicators police are trained to look for is an indication of alcohol in the blood system based on how the driver's eyes are able to follow a finger or pen in front of their face. CHP officers will check the eyes for lack of smooth pursuit, whether there is a stop-and-go movement of the eyes tracking a pen, or finger, instead of the eyeballs smoothly following the path of the pen.

There are other field sobriety tests, “FSTs,” that police officers will conduct. Most people feel like they passed the FSTs. However, the police are not looking for a pass or fail in most situations, but to gather detailed facts about what was not exactly right according to them, and what they have been specifically trained to spot as signs of intoxication. (The prosecutor will later use these details in court to try to show a "totality of the circumstances" that demonstrates that the driver was intoxicated while driving.) The police officer will have written down those details and submitted it to the prosecutor for the DUI case in court, and to the DMV for the DUI case at the APS Hearing. 

Regardless of the field sobriety tests, police will take note if a driver admits to having several drinks and then driving. Making such an admission of drinking and driving usually is not freely provided by drivers–at least the driver does not feel that it was. However, being detained and asked questions by an LAPD officer or other armed officer can be intimidating. Most people feel like they are forced to answer questions from the police. Nonetheless, because it is a traffic stop and or brief detention, law enforcement officers, whether Manhattan or Redondo Beach Police, or police in Orange County, California, are not required to give Miranda warnings before asking the question, "Have you had anything to drink?" or any other DUI investigation question. Not until you are arrested and are in custody, do they have to Mirandize the driver before interrogating the arrestee.

Once a California Highway Patrol officer has decided to detain the driver for a DUI investigation, they will conduct the field sobriety tests, as mentioned above. These include small balance or instructional tests that seem simple. For example, there is a walk-and-turn test that involves walking heel to toe, and a one-leg balance test. Once the CHP officer claims to have observed several small deviations, such as missing steps, not counting the right way, etc., she will decide she has probable cause to make the DUI arrest.

To strengthen their investigation, before arresting someone for a DUI, the officer will ask the driver if they would like to take a breath test. If the person declines, they will still arrest. If the person submits, even if the alcohol is below .08% BAC, blood alcohol content, they will probably still arrest for unsafe driving while under the influence of alcohol.

The roadside handheld breath test measures blood alcohol content. The driver blows into the device. In theory, the device measures the amount of alcohol being eliminated by the lungs from the blood. The alcohol in the air is presumably from the lungs. The measurement, in theory, can be translated into BAC, blood alcohol content. To avoid risk of alcohol not from in the lungs, Los Angeles Police officers are supposed to watch for 15 minutes to make sure the person is providing a clear breath sample.  However, a person blowing into the device could give a false reading if they have alcohol fumes in their mouth from their stomach or particles of food. There are other problems, too, with these devices. Some people have trouble blowing hard enough or if the device is not properly maintained may not give an accurate reading or may not work properly at all. If it does not give a reading, police officers often yell at the detainee, accusing them of not blowing hard enough. However, these devices simply do not work all the time.

Regardless, by the time a breath test is being conducted, the officer has probably already decided that they are going to make an arrest. It usually does not matter what the results are of the roadside breath test as to whether the arrest will occur.

It is possible that if a person takes the roadside breath test and the BAC is low, that might, on rare occasions, increase the chance of not being arrested and charged with a DUI misdemeanor. (For example, I had a case for another issue where my client was driving a golf cart without seatbelts and rolled through a stop sign. My client admitted to drinking beer. The police did a thorough DUI investigation but the handheld breathalyzer showed low blood alcohol. These officers released my client with only an infraction ticket–no DUI arrest. Again, this is not common.) In hindsight, some people wish they would have submitted to the roadside breath test, while others regret submitting to the test.    

Rejecting the roadside breathalyzer is different than refusing to submit to a chemical test after being arrested. The pre-arrest breath testing device is called a preliminary alcohol screening device, PAS. The post-arrest testing is called a chemical test, the results count for the DMV and criminal case.

The post-arrest test may be another breathalyzer, usually a larger device at the police station. The other option is a blood draw, an intravenous shot/needle in the arm to withdraw blood. (Note that refusing a chemical test after being arrested for an alleged DUI can have serious consequences even though it can avoid evidence for the prosecutor’s case–but this is for another discussion.)

The police will submit the blood alcohol results and their police report of the DUI investigation to the Driver Safety Division of the California Dept. of Motor Vehicles and the local prosecutor. The prosecutor may be for the county, like the Los Angeles District Attorney, or for a specific city, like the Hermosa Beach City Prosecutor. The prosecutor uses the police report to build the DUI case.

There are two different criminal charges for essentially the same DUI, California Vehicle Code sections 23152(a) and CVC 23152(b). Subsection “a” reads, “It is unlawful for a person who is under the influence of any alcoholic beverage to drive a vehicle.” A breath test is not required for this section. The prosecutor has to show impaired driving, simply put, unsafe driving because of drinking alcohol–no breath test is required. In contrast, subsection “b” reads, “It is unlawful for a person who has 0.08 percent or more, by weight, of alcohol in his or her blood to drive a vehicle. . .” Here, there must be a test that specifically measures the quantity of alcohol in the blood.

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​​California Criminal Defense Attorneys

DUI Arrest

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Driving Under the Influence of Alcohol