A failed field sobriety test can become the centerpiece of a DUI prosecution. These roadside exercises are graded subjectively by the administering officer, and factors like fatigue, uneven pavement, or medical conditions can produce a failing result even when you are completely sober. What most California drivers do not know is that field sobriety tests are entirely voluntary. Refusing carries no legal penalties under state law. A Contra Costa County DUI defense attorney at The Law Offices of Johnson & Johnson can protect your rights during and after a DUI stop in the Bay Area.
What Officers Are Really Asking You to Do
Field sobriety tests are a series of physical and cognitive exercises that law enforcement officers use during traffic stops to assess whether a driver may be impaired. The National Highway Traffic Safety Administration (NHTSA) has validated three standardized tests for use in DUI investigations:
- The horizontal gaze nystagmus (HGN)
- The walk-and-turn test
- The one-leg stand
Officers in Contra Costa County and throughout California may also request non-standardized tests like finger-to-nose or counting backward, though these lack scientific validation.
These tests are designed to measure coordination, balance, and your ability to follow instructions at the same time. However, their results depend heavily on the subjective judgment of the officer administering them. Factors unrelated to alcohol, such as uneven road surfaces, poor lighting, footwear, fatigue, age, and medical conditions, can all affect performance and produce results that suggest impairment where none exists.
Your Right to Refuse in California
Field sobriety tests are entirely voluntary under California law. Unlike chemical tests, which fall under the state’s implied consent statute, there is no legal requirement to perform roadside exercises during a DUI stop. You can politely decline, and the officer cannot penalize you for doing so. There are no fines, license suspensions, or criminal consequences for refusing a field sobriety test.
This is an important distinction that many drivers miss. California’s implied consent law under Vehicle Code §23612 requires drivers to submit to a chemical test, either breath or blood, after a lawful DUI arrest. Refusing a chemical test after a lawful arrest triggers serious consequences, including a mandatory one-year license suspension for a first offense and additional jail time if convicted. Field sobriety tests do not fall under this statute. They are an investigative tool used before an arrest, not a legal obligation.
One narrow exception applies to drivers under 21. California’s zero-tolerance law requires underage drivers to submit to a preliminary alcohol screening (PAS) breath test during a traffic stop. Drivers currently on DUI probation face similar requirements under the law. For all other adult drivers not on probation, the right to refuse field sobriety tests is well established.
What Happens After You Say No
Declining a field sobriety test does not guarantee you will avoid a DUI arrest. Officers can still make an arrest based on other observations, including the odor of alcohol, slurred speech, bloodshot eyes, or erratic driving patterns. However, refusing removes a significant piece of evidence that prosecutors frequently rely on to build their case.
Field sobriety test results are among the most commonly challenged forms of DUI evidence, even when drivers agree to take them.
Officers must administer the tests according to strict NHTSA protocols, and deviations can render the results unreliable. The most current NHTSA-sponsored field validation study found the one-leg stand to be 83% accurate and the walk-and-turn 79% accurate in identifying drivers at or above 0.08% BAC. Even those figures have been challenged by independent researchers who argue the results are skewed by the disproportionate number of highly intoxicated subjects in the study sample.
By declining, you eliminate the possibility of a subjective and potentially inaccurate assessment being used against you in court. Your refusal may be noted by the officer and could be mentioned at trial. Prosecutors sometimes argue that refusing suggests the driver knew they would fail. A defense attorney can counter this argument by emphasizing that exercising a legal right is not evidence of guilt and that the law imposes no obligation to participate.
How a DUI Stop Typically Works in Contra Costa County
Understanding the sequence of events during a DUI stop can help you make informed decisions if you are ever pulled over. A typical stop in California follows a predictable pattern, and knowing where your rights apply at each stage matters.
The officer first observes a traffic violation or signs of impaired driving. After pulling you over, they look for physical indicators of intoxication such as the smell of alcohol, red eyes, or difficulty producing your license and registration. The officer may then ask you to step out of the vehicle and perform field sobriety tests. This is the stage where your right to refuse applies, and you can decline without legal consequence.
If the officer believes probable cause exists based on their observations, they will place you under arrest and request a chemical test. At that point, California’s implied consent law takes effect, and refusing the chemical test carries its own penalties separate from any DUI charge. Knowing how the DUI arrest process works and which tests you are required to take versus which ones you can decline is one of the most important things a driver in California can understand.
Protect Your Rights After a DUI Stop in the Bay Area
If you were arrested for DUI in Contra Costa County after performing or refusing a field sobriety test, the outcome of your case may depend on how the stop was conducted and what evidence the prosecution holds. The Law Offices of Johnson & Johnson have defended more than 2,000 clients across the Bay Area in criminal and DUI cases. Reach out to the firm today to discuss your situation and explore how to challenge the evidence against you.