Roadside Sobriety Tests: FAQs

Over the past few years, mouth swab tests (or “MSTs”) have been receiving a lot of attention in the media as they are the latest innovation in roadside sobriety testing technology. MSTs enable law enforcement officials to check whether drugs are present in a driver’s system by simply swabbing the inside of the driver’s cheek. However, traditional forms of roadside sobriety tests, such as blood and breath tests are still being used throughout California as well. To answer some questions that they are frequently asked at My Rights Law about modern, as well as traditional, roadside sobriety testing in California, they have put together the following Q&A article.

If you have additional questions, feel free to give their San Bernardino law office a call at (909) 361-6767.

Q: What is roadside sobriety testing?

A: Roadside sobriety testing occurs when a police officer uses one or more field sobriety tests in order to determine if an individual is intoxicated due to alcohol and/or drugs. Field sobriety testing is most commonly conducted on the side of the road by an officer who has pulled over a driver whom they suspect of driving while intoxicated.

Police officers in California can use a few different types of roadside sobriety tests in order to determine if a driver is under the influence of drugs and/or alcohol. The most common of these tests are breathalyzer tests, mouth swab tests, and the standardized field sobriety test.

Q: What is the standardized field sobriety test?

A: The standardized field sobriety test (SFST) is a set of three roadside tests that were developed in the 1970s and are frequently used today in order to determine whether or not a driver is impaired. These three tests are:

(1) The Horizontal Gaze Nystagmus Test: To perform this test the officer holds a small object (usually a pen or flashlight) in front of the driver’s face and then asks him/her to track the movement of the object with their eyes as it is moved horizontally from side to side. A sober individual will be able to smoothly track the object with their eyes, however, an intoxicated individual’s eyes will involuntarily jerk as the stimulus moves from back and forth.
(2) The Walk-and-Turn Test: During this test the driver is instructed to take nine steps along a straight line, touching heel-to-toe each step of the way, then he/she must turn around on one foot and walk back along the line in the same manner. This is what is known as a “divided attention” test as the driver is forced to listen to simple instructions while performing simple physical movements. During this test, the officer looks to see if the driver cannot keep their balance, pauses to regain their balance, does not walk heel-to-toe, uses their arms to balance, takes an incorrect number of steps, steps off the line, etc.
(3) The One-Leg Stand Test: Here the driver is requested to stand on one foot, hold the other foot approximately six inches off the ground, and count aloud (starting with the number one thousand) until told to stop after 30 seconds. The officer looks to see if the driver sways from side to side, uses their arms to balance, hops, or lets their raised foot touch the ground.

Q: Are the standardized field sobriety tests reliable indicators of intoxication?

A: Back in 1998 the National Highway Traffic Safety Administration conducted a study that found that, when correctly administered, the horizontal gaze nystagmus test allows for proper classification of approximately 88 percent of subjects, the walk-and-turn test for 79 percent, and the one-leg stand test for 83 percent.

These standardized tests are designed to be subjective, but their reliability is often attacked as there are many factors that can cause an unimpaired driver to fail one or more of these tests. For example, age, injury, disease, sloped testing area, limited knowledge of English, etc. can all cause a sober individual to fail a standardized field sobriety test. Therefore, a police officer who is administering these tests should ask the driver if there is any reason why they cannot perform the tests, and the driver’s response should be noted in the police report.

Q: Can I refuse to take a field sobriety test in San Bernardino?

A: Under California law, most drivers are not required to submit to roadside sobriety tests. Therefore, you may be perfectly within your legal rights to politely decline to participate in any roadside sobriety test that you are presented with (unless you are under 21 years old or are on probation for driving under the influence).

However, it must be noted that legally speaking, there is a huge difference between a field sobriety test that occurs before a DUI arrest and a chemical test that takes place after a DUI arrest. Drivers may not be legally obligated to participate in roadside sobriety testing that takes place before a DUI arrest. However, under California’s implied consent laws a driver who is arrested for driving while intoxicated is legally obligated to submit to chemical testing after their lawful arrest.

Roadside Sobriety Tests: FAQs

More Questions about Field Sobriety Tests? Contact San Bernardino DUI Attorney Bobby Shamuilian