Field Sobriety Tests in California: Do You Have to Take Them?

Blue lights behind you, an officer asking you to step out and "follow my finger" or walk a straight line — it's a stressful moment, and most people comply without realizing they may have a choice. So do you actually have to perform field sobriety tests in California? This post explains, in general terms.

This is general information, not legal advice. If you're facing a DUI, talk to an attorney about your specific situation.

What field sobriety tests are

Field sobriety tests (FSTs) are the physical roadside exercises an officer uses to look for signs of impairment — things like the walk-and-turn, the one-leg stand, and the eye-tracking test (horizontal gaze nystagmus). They're investigative tools, designed to help an officer build probable cause to arrest you.

Are they mandatory? Generally, no

For most adult drivers, field sobriety tests are voluntary in California. You are generally not legally required to perform them, and unlike refusing a post-arrest chemical test, declining FSTs doesn't carry the same automatic license penalty. Many people don't realize this and perform tests they weren't obligated to do.

This is different from the chemical test given after a lawful arrest (breath or blood), which California's implied consent law generally does require, and refusing that test carries serious consequences. Don't confuse the two: the roadside physical exercises are usually optional; the post-arrest chemical test usually is not.

Why FSTs are easy to "fail"

Field sobriety tests are difficult to perform well even when completely sober. Nerves, uneven roadside pavement, poor lighting, traffic rushing past, fatigue, footwear, age, weight, and medical or balance conditions can all make a sober person look impaired. Because the officer is also the one scoring you, the results are inherently subjective — which is one reason FST evidence can often be challenged.

What to do at the roadside

There's no one-size-fits-all script, but the general framework most people find useful: stay calm and polite, understand that the roadside physical tests are usually optional for adults, and remember that the post-arrest chemical test is a different matter governed by implied consent. If you've been arrested, contact an attorney promptly — including about the short deadline to protect your license through the DMV.

Frequently asked questions

Can I politely decline field sobriety tests? For most adults, yes — they're generally voluntary. Declining them is not the same as refusing the post-arrest chemical test.

Will declining make me look guilty? An officer may still arrest you based on other observations, but you're generally within your rights to decline the physical roadside tests.

Is the eye test (HGN) reliable? It's one of the more technical tests and depends heavily on proper administration, which can be challenged.

What about the handheld breath test at the roadside? That's a separate screening device (the PAS test), generally optional for adults 21+ not on DUI probation — but the chemical test after arrest is required under implied consent.

Arrested after a DUI stop in Sonoma County?

If you're unsure whether your stop and the tests were handled properly, it's worth having them reviewed. Chambers Defense offers a free, confidential consultation.

Call 415-849-7676 today.