California DUI statutes impose designated alcohol limits for adult motorists at 0.08% blood alcohol concentration (BAC). The legal limit is even lower for underage motorists, ride-share drivers, taxi drivers, and commercial drivers. Sometimes, you will face drinking and driving charges even when the BAC is below the designated limit. Your BAC during apprehension determines if you will face DUI charges or a possible conviction. Therefore, if you face these charges in Bakersfield, you should understand the meaning of BAC and how it affects your case. At Koenig Law Office, we have explained BAC to assist you in understanding your DUI offense.

BAC Definition

BAC is the quantifiable alcohol level in a driver’s bloodstream. Other terms synonymous with BAC are blood alcohol level or content.

DUI laws denote or express BAC as a percentage of grams of alcohol in every 100 milliliters of your blood. A 0.08% BAC means every 100 milliliters of your blood contains eight grams of alcohol. A higher percentage shows the alcohol levels in your bloodstream are high, while a smaller percentage shows the levels are minimal.

When the alcohol levels are high, you are more likely to operate a car while impaired because high levels of alcohol impair your capacity to drive carefully as an ordinary person would in the same situation.

BAC Measurement

After a traffic stop, the stopping officer can request to administer a blood or breath test to establish your BAC as a driver. The officer can perform the checks at the apprehension point, the nearest police station, or a hospital. The most reliable measurements are blood or breath tests, and their results are admissible as discovery in court. Let us discuss these tests further.

Breath Tests

Police officers prefer to test motorists’ BAC using breath tests because they are highly convenient. The tests are quick, as they give instant results, and non-invasive, as you only need to breathe into the breathalyzer device. The machine analyzes your deep lung air to determine your BAC.

These checks do not quantify the alcohol percentage in your bloodstream. Instead, the tests measure the deep lung air from the deepest section of the lung closest to your blood supply. Breathing into the breathalyzer mathematically converts the alcohol levels detected in the deep lung air into an equivalent blood alcohol proportion using the partition ratio.

The ratio varies, but DUI statutes in California have set it at 2100:1. This infers that the alcohol levels present in 2,100 milliliters of your deep air lung are legally equivalent to one milliliter of blood alcohol.

Pre-Arrest Breath Tests

Otherwise known as preliminary alcohol screening (PAS), pre-arrest breath tests are conducted after the road traffic stop or sobriety checkpoint before an apprehension for drinking and driving. These tests are not mandatory unless you are underage or on drinking and driving probation for a prior offense.

Post-Apprehension Breath Tests

If the PAS tests show that you are driving while drunk or show intoxication signs, the stopping officer will have probable cause for your arrest. After the apprehension, you will be moved to the local police station, where the officer will administer a post-apprehension blood or breath test. Many arrestees opt for the breathalyzer test because it is minimally invasive.

Breath tests after an apprehension are mandatory. Refusal to submit a sample for chemical testing has severe repercussions, including driving privileges suspension for over twelve months. Additionally, you will face nine months of DUI School instead of three and additional jail time after a DUI conviction. The breathalyzer test taken at the local station is the same as the PAS test, which is administered on a desktop device.

Nevertheless, some counties allow officers to conduct post-apprehension breath tests on the roadside, just like PAS tests. The only difference is that the post-arrest checks are mandatory. Some circumstances can allow you to decline to take the tests or give you an advantage when you take the tests and the BAC is beyond the designated limit, as your DUI lawyer can contest the accuracy of the results for a charge reduction or dismissal.

Blood Tests

Unlike breath tests, DUI blood tests openly check the alcohol levels in your bloodstream, making them highly accurate and reliable if they follow the procedures provided by the law.

A state-accredited officer draws the blood sample, which is sent to a government laboratory for chemical testing. The testing process takes days, so you will have to wait several weeks before knowing the results. Only a portion of the sample goes to the lab, and the other is preserved for future testing if you need a retest or your lawyer wants to conduct an independent test.

The benefit of choosing blood over a breath test is that a portion of the blood sample is preserved, and your lawyer can use it to obtain a second opinion. At the Koenig Law Office, we will bring a blood split petition to court to obtain the saved blood sample for autonomous testing. When the results from our sample differ from those provided by the prosecutor, our attorneys will challenge the reliability and accuracy of the results.

Urine Test Admissibility

Urine tests are methodically accurate in detecting alcohol levels in the blood. Still, they are rarely used in California drinking and driving cases because they are not as reliable as blood and breath tests.

You can only submit a urine sample for testing if breath and blood samples are unobtainable or you cannot take one of these tests, and the one you can take is unavailable.

What can make one incapable of submitting a blood or breath sample for testing? If you have a blood clotting or breathing condition, submitting samples for testing will not be possible. Also, submitting a breath sample will be challenging or unmanageable if you are unconscious or extremely drunk.

The Accuracy of Blood and Breath Tests in Drinking and Driving Cases

Chemical tests administered in DUI incidents to determine BAC are scientifically accurate, and the test results are acceptable as discovery. However, even if these results are admissible, their accuracy depends on the circumstances in which they were taken.

Blood tests in California will be deemed inaccurate in the following situations:

  • The officer taking the blood sample did not follow the right procedures for drawing the blood.
  • The blood sample was not stored properly as the law requires and, therefore, could have been contaminated.
  • The blood vial had inadequate anticoagulants and preservatives.
  • The officer took too long after the arrest to procure the blood sample.
  • The phlebotomist who procured the sample had an expired license.

Your attorney will cite these mistakes during prosecution to cast doubt in the minds of the jury on the accuracy of the blood test results. Also, the legal expert can cite the mistakes made by the officer or phlebotomist drawing the blood sample to convince the prosecutor to drop or lower the charges.

Compared to blood tests, breath tests are less reliable, but the results will be more inaccurate if:

  • The breathalyzer tests mouth alcohol instead of deep lung air.
  • You have an inconsistent breathing pattern.
  • External interferences like temperatures and radio frequency interference (RFI) hamper breathalyzer utility.
  • You have medical conditions like GERD or diabetes.
  • You use certain medication.

Burping during a breath test alone can result in a falsely high BAC.

California's BAC Designated Limit

California has a prescribed blood alcohol level limit that every motorist must observe. The limits vary. Any party that operates an automobile with a BAC exceeding the designated limit is deemed to be driving under the influence, and the prosecutor only relies on these test results for a conviction. They do not need to show that you were impaired.

The Vehicle Code (VC) sections that address prescribed BAC limits are:

  • VC 23152(b) prohibits adult non-commercial drivers from operating automobiles with a BAC above 0.08%.
  • VC 23140 discourages persons under 21 from operating autos with at least .05% BAC.
  • VC 23152(d), prohibiting commercial drivers from driving with at least 0.04% BAC.
  • VC 23152(e), which makes it an offense for taxi, limo, or ride-share drivers to operate vehicles with a 0.04% BAC.

Additionally, the state has two zero-tolerance laws for underage motorists and drivers on drinking and driving probation. It is illegal for these individuals to operate automobiles with at least 0.01% BAC.

It is worth understanding that you can still face DUI apprehension even if your BAC is within the prescribed limit. However, unlike under the “per se” code sections where the prosecutor relies on test results, VC 23152(a) does not rely on the test results as they are within the designated limit. However, the jury will find you liable if the prosecutor demonstrates that you manifest signs of intoxication.

Usually, the police will stop you if they believe you violate traffic laws or drive recklessly. The officer will ask you to perform field sobriety tests when they stop you for suspicion of drinking and driving. Besides, law enforcement will find intoxication signs like red-shot eyes, alcoholic breath, a lack of focus, and slurred speech. These manifestations and poor performance in FSTs will give the officer a good reason to arrest you.

BAC Use in DUI Traffic Stops and Arrests 

The police rely on BAC in two instances. The first is during drinking and driving investigations, and the other is during arrest.

  • BAC Measurement During Investigations

The law allows the police to make a stop if they suspect you are violating the law. Another time the police can stop you in traffic is at a sobriety checkpoint. Therefore, when you approach a road traffic stop or DUI checkpoint, you should slow down and pull over.

After you stop, the police will approach your vehicle to inspect your license and vehicle. If law enforcement believes you are intoxicated, they will begin an investigation. The investigations involve asking you to undergo a pre-arrest breath test. If the results come out below the prescribed limit after blowing the breathalyzer, you will be free to leave. However, if the PAS test shows you have an illegal BAC, the police will arrest you. After the apprehension, you will undergo a post-apprehension breath or blood test.

You should understand that if you believe your BAC results will be positive, you should politely decline the PAS test, but only if you are an adult. Either way, the officer will arrest you. Besides, you can turn down the tests if you believe your BAC is within the prescribed limit. However, if you are under 21 or on drinking and driving probation, there are consequences for declining PAS tests.

  • Post-apprehension Chemical Testing

Once officers arrest you on DUI suspicions, they administer a post-apprehension chemical test. You can choose between a breath and blood test, although sometimes the investigator can ask you to undergo a blood test with or in place of a breath test if they reasonably suspect drugs have intoxicated you. The tests at this stage are evidentiary, and the results are allowable as proof of drinking and driving during prosecution. These tests are mandatory for everyone, and refusal to submit to testing will result in severe repercussions, including license suspension by the Department of Motor Vehicles (DMV).

  • Title 17 Regulations and Alcohol Chemical Testing

Law enforcement must follow strict regulations and procedures provided for under Title 17 during DUI investigations. The regulations guide how to draw samples, calibrate and maintain testing devices, and interpret the results. If these regulations are disregarded during investigations, your criminal defense attorney will poke holes in the result’s accuracy for a favorable ruling.

BAC in DUI Prosecution

During prosecution, the prosecutor uses the BAC test results and other proof to demonstrate that you were driving with a blood alcohol level above the prescribed limit and hence guilty of drinking and driving per se or that you were physically compromised and guilty of a VC 23152(a) violation.

In a per se DUI charge, the prosecutor relies on the chemical test results to show that your actual BAC exceeded the prescribed limit. If the measurement exceeds the designated limit, you are too drunk to drive, and the jury will find you guilty.

Driving under the influence under VC 23152(a) is subjective. The prosecutor relies on the BAC test results and cites signs of impairment as evidence that you could not operate the motor vehicle soberly like an ordinary person would under the same circumstances. Other evidence the prosecutor relies on to show that you were drinking and driving are:

  • The testimony from the apprehending officer.
  • Proof that you drove the auto.
  • Witness testimonies.

Breath vs. Blood Tests

Which blood or breath test should you pick when apprehended for a DUI in California? The answer to the query is complex because each of the chemical tests has merits and demerits.

Once apprehended, stay calm and polite and say little to the stopping officer. Even if the officer seems friendly, do not disclose crucial information because you could make self-incriminating statements that will be used against you in court. Your chemical test results are not the only proof the prosecutor presents in court. Your statement and conduct at the scene will be part of the evidence, so you must be careful with your statements and have your defense lawyer present when answering questions.

Many DUI arrestees prefer breath tests because of the following benefits:

  • They are painless and minimally invasive.
  • They are quick to administer, and the test results are immediate.

Blood tests are preferred because part of the sample can be saved for independent testing, unlike a breath test with no retesting. Also, blood testing allows for a more accurate BAC evaluation than a breath test and is therefore suitable when you believe your BAC is within the designated limit. 

The downside of blood tests is that they are painful and invasive as blood is drawn. They also take several minutes to perform, as the officer drawing the blood can have problems spotting a workable vein. Besides, you will have to wait several weeks before obtaining the results.

Another significant difference is that with blood tests, the apprehending officer does not confiscate your license immediately. The license suspension only starts after test results confirm you were intoxicated beyond the designated limit, which takes weeks. Nevertheless, the results are immediate when you opt for a breath test. Law enforcement will confiscate your physical license immediately after the test results come out positive.

After license confiscation, the officer will issue you a temporary license valid for 30 days. You should request a DMV hearing within ten days after the arrest to prevent license suspension after the lapse of the temporary license in 30 days. If you do not request a hearing within ten days, the DMV will automatically suspend your driving privileges after thirty days.

Find a Profound Drinking and Driving Defense Attorney Near Me

If you face DUI charges in Bakersfield, we invite you to contact the Koenig Law Office at 661-793-7222 for a free case discussion. We understand court processes, and the likelihood of a positive outcome is high with us by your side. We will challenge the BAC result’s credibility for a charge reduction or dismissal.