The Science Behind Breathalyzers: When and How to Challenge BAC Results

Getting pulled over on the I-10 or I-215 in San Bernardino County is an intimidating experience. If an officer asks you to blow into a machine, you might think the result is an absolute truth. This is a massive mistake. Breathalyzers are not perfect, and the numbers they produce are often wrong. We are here to pull back the curtain on the technology and show you the science behind breathalyzers: when and how to challenge BAC results.

At Patrick Silva, Attorneys at Law, we treat every DUI case like a battle. We know that police officers make mistakes and machines fail. We do not just accept the prosecution’s evidence. We tear it apart. Our deep understanding of DUI defense enables us to recognize flaws in the system that other lawyers might miss.

California DUI Statutes and the Legal Standard

California law is strict when it comes to drinking and driving. Under California Vehicle Code Section 23152(a), it is illegal to drive while under the influence of alcohol. Additionally, Vehicle Code Section 23152(b) makes it a crime to drive with a Blood Alcohol Concentration (BAC) of 0.08 percent or higher.

The law creates a rebuttable presumption. This means if you test at or above 0.08 percent within three hours of driving, the court can assume you were over the limit while behind the wheel. Even so, this presumption is not a conviction. It is merely a starting point for the prosecution, and we have the tools to fight it.

The Flawed Science of Breath Testing

Most people believe a breathalyzer measures the alcohol in your blood. It does not. Instead, it measures the alcohol vapor in your breath and uses a mathematical formula to estimate your blood levels. This formula assumes a partition ratio of 2,100 to 1. In simple terms, the machine assumes that every person has the exact same body chemistry.

Science tells us this is false. Factors like body temperature, lung capacity, and even hematocrit levels can skew the results. If your body does not match the machine’s rigid mathematical model, your BAC reading will be artificially high.

Alveolar Air vs. Mouth Alcohol

A valid breath test must capture alveolar air, which comes from deep within the lungs. If the machine picks up mouth alcohol, the result is worthless. Mouth alcohol can come from recent drinking, but it can also come from health issues. When the machine detects alcohol from your mouth instead of your deep lung tissue, it can report a level far higher than your actual blood concentration.

Title 17: The Rules Law Enforcement Must Follow

California has a specific set of regulations called Title 17 of the California Code of Regulations. These rules dictate exactly how chemical tests must be conducted. If the police violate even one of these rules, the evidence against you becomes vulnerable. We know these rules better than the officers who are supposed to follow them.

The 15-Minute Observation Period

According to Title 17, Section 1219.3, an officer must continuously observe the subject for at least 15 minutes before the breath test. During this time, you must not eat, drink, smoke, vomit, or regurgitate. If you burp or have acid reflux, the clock must restart. Officers in Redlands and across San Bernardino County often cut corners here. They might start paperwork or talk to a partner instead of watching you. We use this lack of attention to challenge the test’s validity.

Calibration and Maintenance Standards

The machines used by the San Bernardino County Sheriff’s Department must be checked for accuracy. Title 17, Section 1221.4 requires that breath alcohol instruments be checked every 10 days or after 150 subjects, whichever comes first. If the logs show the machine was not maintained properly, the results should not be used against you in court.

Common Reasons to Challenge Inaccurate Results

We look for every possible error in your case. Some of the most common ways we win involve highlighting medical or environmental factors that the police ignored.

• Medical Conditions: Conditions like GERD, acid reflux, or heartburn can cause alcohol vapors from your stomach to enter your mouth. This creates a false high reading
• Dietary Issues: Low-carb diets or diabetes can cause your body to produce ketones, which some machines can mistake for alcohol
• Poor Officer Training: Many officers fail to follow the National Highway Traffic Safety Administration (NHTSA) guidelines. We are educated in these standards and can expose an officer’s incompetence during cross-examination

Navigating the San Bernardino County Justice Center

If you are charged with a DUI in this area, your case will likely be heard at the San Bernardino Justice Center. The prosecutors here are aggressive, but so are we. We represent people in both the criminal court system and at DMV proceedings.

Remember that you only have 10 days from the date of your arrest to request a DMV hearing. If you miss this deadline, your license will likely be suspended automatically. We handle these hearings to protect your right to drive while we fight the criminal charges.

Contact Us for Aggressive Defense from a Proven California Law Firm

We represent the falsely accused. We have spent years studying the science of DUI defense so we can provide a level of representation that few others can match. We know how to cross-examine officers on their failures. We know how to subpoena maintenance logs and reveal machine errors. We have won many cases because we refuse to back down.

If you are facing a DUI in Redlands or anywhere in San Bernardino County, you need a firm that knows how to win. Do not let a machine’s faulty number ruin your life. We are here to provide the facts and the fight you need.

Call Patrick Silva, Attorneys at Law, today at 909-500-4819 for a free consultation. We will look at your case, explain your options, and show you why we are the right team to stand by your side.