The Hand Pat Test – A DUI Field Sobriety Test

The hand pat test is a non-standardized field sobriety test (FST).  Law enforcement officials, including those from the California Highway Patrol (CHP) and the Los Angeles Police Department (LAPD), occasionally administer the hand pat test in order to gauge whether a DUI suspect is under the influence of alcohol and/or drugs.¹

During the administration of the test, the DUI suspect is to:

• Place one hand extended, palm up, out in front of him/her. The other hand should be placed on top of the first, with the palm facing down.
• The top hand should then begin to pat the bottom hand.
• The top hand should rotate 180 degrees, alternating between the back of the hand and the palm of the hand. The bottom hand remains stationary.
• The DUI suspect should then count out loud, “ONE, TWO, ONE, TWO, ONE, TWO, etc.,” in relation to each pat.²

During the administration of the hand pat test, police officers usually consider the following four factors in determining whether or not a suspect is impaired.

• Ability to follow instructions
• Ability to count correctly
• Rotation and sequence of the hand patting
• When the subject starts and stops the test.³

The hand pat test has not been approved by the National Highway Transportation Safety Administration (NHTSA).

As a result, law enforcement officials are not obligated to follow any specific procedures nor look for any specific indicators of impairment when conducting the hand pat test.

Clearly, this lack of standardization adds irregularity and inaccuracy within the testing process. Any knowledgeable criminal defense attorney should therefore be able to expose such invited subjectivity as a potential chink in the prosecution’s armor.

In the article below, our California DUI lawyers will explain:

1. Field Sobriety Tests & DUI Investigations

2. Hand Pat Test Instructions

3. Hand Pat Test Clues

4. Hand Pat Test Reliability

You may also find it useful and informative to visit our page on Field Sobriety Tests in DUI cases.

1. Field Sobriety Tests & DUI Investigations

There are only three NHTSA standardized field sobriety tests. The hand pat test is not one of them. The three standardized FSTs are:

• the horizontal gaze nystagmus test (HGN),
• the walk and turn test, and
• the one-leg stand test⁴

These three tests are nationally “standardized” because they are part of several government-approved studies that establish a statistically significant correlation between the three tests and DUI impairment.⁵

Nevertheless, non-standardized FSTs such as the hand pat test are also frequently used by law enforcement to aid their DUI investigations.

Specifically, along with the hand pat test, other non-standardized FSTs used by police officers to determine whether or not a suspect is driving under the influence include:

• the finger count test,
• the Rhomberg balance test, and
• the finger to nose test.

As noted by our California DUI defense lawyers in subsection four, the hand pat test is not necessarily a reliable and/or accurate test in determining whether or not a suspect is driving under the influence.

2. Hand Pat Test Instructions

The hand pat test instructions are specifically designed to have a subject divide his/her attention between simple mental and physical tasks.⁶

Below are the instructions usually given by police officers when conducting the hand pat test.

Nevertheless, because there are no standard guidelines for administrating the hand pat test, the instructions provided below may vary significantly from one officer to another.

STEP 1:

Start by instructing the DUI suspect to stand with his/her feet together and arms to his/her sides. Instruct the DUI suspect not to begin until told to do so.

STEP 2:

When told to do so, the suspect should put one hand out in front of him/her with the open palm facing upward.

STEP 3:

The suspect should then place the opposite hand on top of the first hand with the open palm facing downward.

STEP 4:

The suspect should then rotate his/her top hand 180 degrees and pat the back of the top hand to the palm of the bottom hand, while simultaneously counting out loud, “ONE.”

STEP 5:

Have the suspect then rotate the top hand 180 degrees so the palm of the top hand pats the palm of the bottom hand, while simultaneously counting out loud, “TWO.”

• The suspect should keep repeating this process until told to stop.
• The suspect should start at a slow speed then gradually increase the speed until a relatively rapid pace is reached.
• The suspect should perform this test for a minimum of 10 seconds but no more than 15 seconds.⁷

3. Hand Pat Test Clues:

Many of the same necessary exercises used to drive a vehicle are tested with the Hand Pat FST. These tasks include:

• Information processing
• Short-term memory
• Judgment and decision making
• Steady, sure reactions
• Clear vision
• Small muscle control
• Hand coordination.⁸

Officers may, therefore, gauge various indicators of impairment when a suspect performs the hand pat test.

More specifically, California officers often consider the below-mentioned 4 “clues” in determining whether or not a suspect is driving under the influence of alcohol and/or drugs.

CLUE 1: How well the subject follows instructions

• A person who is intoxicated may not have the ability to follow each and every one of the officer’s instructions, in the process failing to perform the test correctly

CLUE 2: Starts too soon

• If the subject starts the test before being told to do so, then the officer will likely perceive this as an indicator of impairment

CLUE 3: The subject does not count as instructed

• Obviously, if the suspect forgets to count or does not count in proper numerical order, then the investigating officer may score this as a clue that the driver is intoxicated.

CLUE 4: The subject does not pat his/her hands as instructed

• Here, the officer looks for whether or not the suspect is correctly rotating (180 degrees) and alternating between the back of his/her hand and the palm of his/her hand⁹

4. Hand Pat Test Reliability

As mentioned earlier, the hand pat test has not been approved by NHTSA.

As a result, there are no federal government-approved studies to quantify the extent of its effectiveness and/or reliability in determining whether or not a particular suspect is driving under the influence of alcohol and/or drugs.

Furthermore, the procedural administration of the hand pat test varies from one police officer to the next.

Thus, when taking into account not only the intrinsic flaws of the test itself, but as well as its subjective administration by law enforcement, the validity/reliability of the hand pat test is highly dubious.

John Murray, a Ventura County DUI lawyer¹⁰ is heralded as one of the premier DUI attorneys in the country. Mr. Murray is highly skilled in revealing missteps on the part of law enforcement during their administration of field sobriety tests.

In terms of the hand pat test, some of the specific weaknesses ripe for attack by Mr. Murray and our other California DUI defense lawyers include:

1. Mental Defects:

• If a driver has inherent mental impairments, language barriers or hearing issues that would obstruct his/her ability to understand instructions, then the test results may be deemed invalid.

2. Coordination failures related to drugs and medicines:

• The lack of proper hand rotation and synchronization that police monitor during the test may in fact be due to causes other than alcohol. Some of these causes include seizure medications, prior injuries, mobility problems, arthritis and age.

3. Non-Standardized Testing:

• Since there are no NHTSA-approved procedures to aid officers in the administration of the hand pat field sobriety test, there potentially exists a lack of sufficient objectivity in each officer’s determination of whether or not a particular suspect is drunk driving.

4.  Outside Distractions:

• The DUI suspect should not have to conduct the test amid roadside interferences. If honking, flashing lights, and/or a myriad of other potential audio/visual distractions surround the testing, then the test results may be deemed unsound.

5. Incorrect Instructions:

• The investigating officer(s) should inform the DUI suspect of the proper rotation, timing and sequence of the hand patting. If the officer does not correctly instruct the suspect on how to conduct the test, then any subsequent test results may be all the more questionable.

References:

¹ California Highway Patrol (December 2007). Memo Re: HPM 70.4. Driving Under the Influence Enforcement Manual. The finger-to-nose FST was among the six optimal DUI field sobriety tests that were examined during the initial 1977 study conducted by SCRI. The finger-to-nose test was also included in a Finnish DUI study conducted in 1974 and was implemented by the LAPD during the formation of their DRE program. The finger-to-nose test is noted for its divided attention qualities and depth perception issues.

² Id., Although the hand pat test has not been tested under government-approved scientific conditions, experienced California officers have indicated that is it an effective and reliable field sobriety test.

³ Id.,

⁴ U.S. Department of Transportation “DWI Detection and Standardized Field Sobriety Testing” NHTSA Student Manual (February 2006).

⁵ See Stuster. U.S. Dept. of Transportation Rep. No. Dot-HS-808-839 (1998), at 33; Burns & Moskowitz, Psychophysical Tests for DWI Arrest, U.S. Dept. of Transportation Rep. No. DOT-HS-802-424 (1977) (recommended the three-test battery of one-leg stand, walk and turn, and HGN to aid officers in discriminating BAC level); Anderson, Schweitz & Snyder, Field Evaluation of Behavioral Test Battery for DWI, U.S. Dept. of Transportation Rep. No. DOT-HS-806-475 (1983) (field evaluation of the field sobriety test battery (HGN, one-leg stand, and walk and turn) conducted by police officers from four jurisdictions indicated that the battery was approximately 80% effective in determining BAC above and below .10 percent).

⁶ California Highway Patrol (December 2007). Memo Re: HPM 70.4. Driving Under the Influence Enforcement Manual.

⁷ Id.,

⁸ Id.,

⁹ Id.,

¹⁰ Ventura County DUI lawyer John Murray is qualified by NHTSA to administer field sobriety tests, in connection with DUI roadside investigations. Attorney Murray practices in Ventura and Los Angeles Counties, including Simi Valley, Van Nuys, San Fernando, Lancaster, Burbank and Glendale.