(FSTs) are used by the police to establish probable cause for administering a preliminary breath test or making a California driving under the influence (DUI) arrest.

Unfortunately, FSTs are highly subjective and often unreliable. Even the most trustworthy field sobriety tests are shown to be only 65-77% accurate at detecting whether the driver is DUI.

Therefore, it is important for California drivers to understand the basics of FSTs before they encounter them.

Standardized FSTs were developed after substantial research by the National Highway Traffic Safety Administration (NHTSA) in order to determine the accuracy of FSTs.

Of all of the FSTs studied, the NHTSA found that three tests proved to be most reliable-the Horizontal Gaze Nystagmus, the One Leg Stand, and the Walk and Turn. These three FSTs became known as the “Standardized Field Sobriety Tests.”

Below is a quick summary of the three tests:

  • Horizontal Gaze (Nystagmus): Officer positions a finger or pen about a foot from a driver’s face, moving it from side to side while watching their eyes for jerking or trembling movements.
  • One Leg Stand: Driver stands with heels together, arms against their sides and counts out loud while raising one leg six inches off the ground, testing their balance.
  • Walk and Turn: Officer instructs a driver to take nine to twelve heel-to-toe steps on a line, turn and repeat them back, looking for mistakes or loss of balance.

Stay tuned to tomorrow’ s blog post for information about additional California field sobriety tests!

Experienced California DUI Defense Attorneys will carefully review the circumstances in which any field sobriety tests were given. In addition, they will determine whether the testing officer adhered to the required protocols and has received the proper training. If not, lawyers most often can get any testimony given by the testing officer thrown out.

Further information about field sobriety tests and California DUI laws can be found at the California DUI Guide website. Drivers are also encouraged to contact an experienced DUI defense attorney if they are arrested for DUI after a field sobriety test.

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