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Introduction
Most people associate DUI arrests in California with breath tests — the kind where you blow into a device and your blood alcohol concentration (BAC) determines whether you’re above the legal limit. But what happens if your breath test comes back under that limit? Can you still be arrested?
The answer is yes. In California, failing a breath test is not the only factor officers consider when deciding whether to arrest someone for driving under the influence. A DUI arrest can happen even if your BAC is below 0.08%, or if the test doesn’t detect alcohol at all. This is because California law allows officers to make DUI arrests based on observed impairment from alcohol, drugs, or a combination of both.
This article breaks down how California DUI laws work in situations where a breath test doesn’t lead directly to an arrest. We’ll explain the broader criteria officers use, how they assess driver behavior, and why passing a breath test doesn’t always mean you’re in the clear. This guide is meant to clarify the process, not provide legal advice, and is written for informational purposes only.
If you’re driving in California, it’s important to understand how DUI arrests can happen even without a failed breath test — especially with increasing enforcement related to drug-impaired driving and other forms of impairment that can’t be measured by a breathalyzer.
How California Defines DUI Beyond the Breath Test
California’s DUI laws focus on impairment, not just breath test results. Under California Vehicle Code Section 23152, a person can be arrested for DUI if they are:
- Driving with a BAC of 0.08% or higher (per se DUI)
- Driving under the influence of alcohol (even if BAC is below 0.08%)
- Driving under the influence of drugs (prescription or illegal)
- Driving under the combined influence of alcohol and drugs
The key point is that “under the influence” doesn’t require a specific BAC level. If a driver’s mental or physical abilities are noticeably impaired and they can’t operate a vehicle safely, they may be arrested for DUI — even if they pass a breath test.
Breathalyzers only detect alcohol, not drugs. This means someone who has used substances like marijuana, prescription medications, or other drugs may show 0.00% BAC but still be impaired. Officers are trained to spot signs of drug impairment and can arrest based on observed behavior and performance on field sobriety tests.
So while a failed breath test may support a DUI arrest, it is not required. California law allows flexibility in how impairment is identified and enforced.
Field Sobriety Tests and Officer Observations
One of the main tools used when a breath test doesn’t confirm impairment is the field sobriety test (FST). These are physical and cognitive tests conducted roadside that help officers assess coordination, balance, and attention — all indicators of potential impairment.
In California, common FSTs include:
- Horizontal Gaze Nystagmus (HGN) – tracking involuntary eye movements
- Walk-and-Turn Test – walking in a straight line and turning
- One-Leg Stand – standing on one foot while counting
Officers also rely on general observations such as:
- Unsteady movement or poor coordination
- Confused or slow responses to questions
- Slurred or mumbled speech
- The odor of alcohol or drugs
- Bloodshot or watery eyes
Even if a breath test shows a BAC below 0.08%, these signs may still support a DUI arrest if the officer believes the driver is not safe to operate the vehicle. In these cases, the focus shifts from numerical BAC readings to behavioral evidence of impairment.
These assessments are subjective but legally valid. An officer doesn’t need a failed breath test to form probable cause for an arrest if other clear indicators of impairment are present.
DUI Arrests Involving Drugs or Mixed Substances
A growing number of DUI arrests in California involve drug impairment rather than alcohol. These are commonly referred to as DUID cases (Driving Under the Influence of Drugs). Breath tests do not detect drugs — this includes marijuana, opioids, anti-anxiety medications, and many other substances.
If an officer suspects drug use, they may request a blood test, which is more accurate for detecting the presence of drugs. Drivers who pass a breath test may still be arrested, transported, and required to provide a blood sample for further testing.
In some cases, drivers may have consumed both alcohol and drugs, which can lead to impairment even if each substance alone might not reach the legal threshold. This combination makes the situation more complex and can support an arrest even if the breath test alone is not conclusive.
California uses Drug Recognition Experts (DREs) in some jurisdictions — specially trained officers who evaluate suspected drug-impaired drivers. Their assessments include checking vital signs, pupil size, muscle tone, and other physical indicators.
Because the effects of drugs vary widely, and some legal medications can cause significant impairment, DUI enforcement in California is increasingly focused on total driver behavior rather than just BAC.
Refusing the Breath Test Doesn’t Prevent Arrest
Some drivers believe that by refusing a breath test, they can avoid arrest — but that’s not the case. In California, refusing to take a chemical test after being lawfully arrested for DUI leads to automatic administrative penalties, including a minimum one-year license suspension for a first offense.
Importantly, refusal does not stop the arrest process. If an officer observes signs of impairment and has probable cause, they can still arrest the driver and seek a warrant for a blood test, particularly in suspected drug cases.
Under California’s implied consent law, all drivers agree to submit to chemical testing if lawfully arrested for DUI. Refusing the test does not make the officer’s observations disappear, and in fact, the refusal itself may be used as supporting evidence that the driver was impaired or attempting to avoid detection.
So even in the absence of a breath test result — or with a passed test — DUI arrests can and do happen based on the total picture presented at the scene.
Officer Discretion in DUI Arrests
California law grants officers significant discretion in determining whether a driver is under the influence. While BAC provides measurable data, officers are not limited to breathalyzer results when forming probable cause.
An officer’s discretion is based on the totality of circumstances, which may include:
- Driving behavior before the stop
- Physical signs of impairment
- Results of field sobriety tests
- Statements made by the driver
- Refusal to cooperate with testing
Even in the absence of alcohol, if a driver is clearly not in control of their faculties — for example, showing confusion, delayed reactions, or erratic behavior — an officer may decide that a DUI arrest is warranted.
This flexibility allows for more accurate enforcement but also highlights why simply passing a breath test doesn’t automatically prevent an arrest. The law is designed to catch all forms of impaired driving, not just those over a certain alcohol threshold.
FAQ Section
Q: Can I be arrested for DUI in California if I blow under 0.08%?
A: Yes. If an officer believes you’re impaired by alcohol or drugs, they can arrest you even with a BAC below the legal limit.
Q: What if my breath test comes back clean?
A: A clean breath test may rule out alcohol, but not drugs. Officers can still arrest you if they observe signs of drug impairment or unsafe driving.
Q: Are field sobriety tests required by law?
A: No, field sobriety tests are voluntary in California. However, refusing them won’t prevent arrest if other signs of impairment are present.
Q: Can prescription medications lead to a DUI arrest?
A: Yes. Legal medications that impair your ability to drive can lead to a DUI arrest, even if taken as prescribed.
Q: What if I refuse the breath test?
A: Refusing a chemical test after arrest leads to automatic license suspension, even if you’re not charged with DUI.
Q: Do I have to submit to a blood test for drugs?
A: If arrested for DUI and suspected of drug use, you may be required to take a blood test. Refusal can result in penalties.
Q: Will I still go to jail if I pass the breath test?
A: It’s possible. If the officer observes clear signs of impairment from drugs or combined substances, they may proceed with an arrest.
Conclusion
In California, passing a breath test doesn’t guarantee you’ll avoid a DUI arrest. Law enforcement officers have the authority to arrest drivers based on behavioral cues, field sobriety performance, and suspected drug use — even in the absence of a failed alcohol test. California’s approach to DUI enforcement goes beyond numbers, focusing on whether a driver appears to be impaired and unable to drive safely.
To better understand the full process behind how DUI enforcement works in the state, visit our main guide on How DUI Laws Work. For more detail on what typically triggers a DUI arrest during a traffic stop, explore our in-depth breakdown here: What Triggers a DUI Arrest During a Traffic Stop.