Category Archives: Field Sobriety Tests

Validity of Field Sobriety Test Questioned

There are many so-called “field sobriety tests” used by officers supposedly to determine a DUI suspect’s sobriety.  And, as I’ve posted in the past (Field Sobriety Tests: Designed for Failure?), these tests are highly unreliable and largely used to justify the officer’s suspicions.  Of the many “tests” used today, only three have been approved by the National Highway Traffic Safety Administration: walk-and-turn, one-leg-stand and horizontal gaze nystagmus (HGN, or the “eye test”).  Collectively, they are referred to as the Standardized Field Sobriety Tests (SFSTs).  Although they are in reality no more valid at determining intoxication than the other tests, their adoption by the federal government has given them an aura of credibility.  The most insidious of these three tests is the nystagmus test – because of its seemingly scientific nature.  Yet, as I’ve previously posted, HGN is unquestionably the least reliable  of the FSTs. (DUI “Eye Test” a Fraud?).  

 A growing number of states are now questioning the validity of such tests, as shown in the following recent news story:

DUI ‘Eye Test’ Under Fire by Supreme Court

State justices join critics, but test has its supporters, too

When it comes to a suspected DUI, the eyes don’t lie.

That’s the principle behind horizontal gaze nystagmus testing, which has long been considered the most reliable way, short of a blood or breath test, for a police officer to determine whether a driver has been drinking.

However, the Illinois Supreme Court has dealt a potentially serious blow to HGN testing with a recent decision stating that such tests are not presumed scientifically valid in Illinois…

“Based on my training and experience, the test is very reliable,” (Dixon Police Department Sgt. Dan) Langloss said. “Yes, the test does have its flaws and drawbacks, but it is only one factor that we look at during a DUI stop. You have to look at the totality of circumstances.”

Many critics across the country, including defense attorneys, argue it is difficult to determine the accuracy of HGN testing and that there are many factors that can cause the eyes to visibly jerk aside from alcohol consumption.

“There are over 25 different types of nystagmus,” said Bob Thompson, Lee County public defender. “Officers are not taught about the other types, which they should know about. Fear, anxiety and viral infections, to name a few, can all have an affect on the eyes.”

Thompson added there are other factors that can affect the results of an HGN test, such as exposure to the lights on the squad car and the difficulty that an officer may have when determining an exact 45-degree angle when conducting the test.

“Officers are not trained in scientific methods or medicine,” Thompson said. “During cross examination, it’s difficult to ask them to draw us a 45-degree angle or test their geometry skills. That’s where we’re starting to see the trial courts become more strict when admitting the test.”

The court ruling came in the wake of a Peoria County case involving Joanne McKown, who was convicted of multiple counts of DUI and reckless driving after she hit three motorcyclists in June 2002. Having suffered a broken toe, she could not perform other sobriety tests, such as standing on one leg or walking heel-to-toe. A sheriff’s deputy who administered an HGN test 90 minutes after the accident said she failed. After McKown refused to give blood voluntarily, police got a search warrant and drew blood 6 1/2 hours after the accident. Tests showed no alcohol in her bloodstream.

Writing that “HGN testing appears to have as many critics as it does champions,” the state Supreme Court sent the Peoria case back to the trial court in September.

For a further discussion of the pseudo-scientific nystagmus test, see my earlier posts: Nystagmus: ”The Eye Test”, Nystagmus: ”The Eye Test” (part 2) and Nystagmus: ”The Eye Test (part 3)”.

(Thanks to John Kruzelock.)

Court Rejects Field Sobriety Test

The most critical evidence in a drunk driving case, after the blood or breath test, is the battery of field sobriety tests administered roadside by the officer before deciding whether to arrest.  These ”tests” are designed in theory to determine any impairment which may affect the safe operation of a vehicle. 

In fact, field sobriety tests (FSTs) simply test the physical skills and experience of the subject; a physically fit officer who has performed them hundreds of times will perform far better than an elderly, overweight, injured or unathletic person who is completely unfamiliar with the tests.  Add to this that the suspect is nervous and/or scared,  is attempting them in the dark late at night, in front of a police car with flashing lights, on a sloped roadside, with cars whizzing by within a few feet, possibly on high heels….Well, you get the picture.    

As I’ve mentioned in past posts, these “tests” are unreliable and highly inaccurate (see Field Sobriety Tests: Designed for Failure? and Are Field Sobriety Tests Valid?).  And this has been clearly demonstrated in scientific research. 

In 1991, Dr. Spurgeon Cole of Clemson University conducted a study on the accuracy of FSTs. His staff videotaped individuals performing six common field sobriety tests, then showed the tapes to 14 police officers and asked them to decide whether the suspects had “had too much to drink and drive”. Unknown to the officers, the blood-alcohol concentration of each of the 21 DUI subjects was .00% — stone sober. The results: the officers gave their opinion that 46% of these innocent people were too drunk to drive! In other words, the field sobriety tests were hardly more accurate at detecting intoxication than flipping a coin. Cole and Nowaczyk, “Field Sobriety Tests: Are they Designed for Failure?”, 79 Perceptual and Motor Skills Journal 99 (1994).

A common reply from police and prosecutors to these criticisms is that one of the FSTs is not affected by any of these considerations:  horizontal gaze nystagmus (HGN).  Basically, this test involves the officer observing and estimating measurements of a suspect’s eyeball movements.  However, the test was never designed for detecting driving impairment nor for determining actual blood-alcohol levels, nor is the officer remotely qualified to administer this opthamological test — and certainly not under roadside conditions.  (See my earlier posts, Nystagmus: the “Eye Test”,  Nystagmus: The ‘Eye Test’ (part 2), Nystagmus: The ‘Eye Test’ (part 3), and DUI ‘Eye Test’ a Fraud?)

Years ago, when HGN was first introduced by police agencies around the country, the courts refused to admit the results into evidence — on the grounds there was no scientific accceptance of the test for determining alcohol impairment.  Gradually, however, and with considerable political pressure from prosecutors and MADD, local courts gradually began admitting HGN into evidence.  And the seemingly scientific nature of the test proved to be very impressive to juries.

Recenly, the Illinois Supreme Court considered whether HGN should continue to be admitted into evidence.  Two days ago they filed their decision:  No — not without a hearing where the prosecution must prove that the test is scientifically accepted.  Illinois v. McKown (Docket No. 102373, filed September 20, 2007).

(Thanks to Illinois attorney Donald J. Ramsell.)

DUI Cop Refuses Breath Test

I posted a few days ago about an Illinois judge who refused to cooperate with officers investigating him for felony DUI, refusing to submit to field sobriety and breath tests. The hypocrisy applies to law enforcement as well:

Officer Honored for DUI Arrests Charged in

Alcohol-Related Crash

Pekin, Ill. Dec. 13. AP – An off-duty central Illinois police officer honored two years ago for cracking down on drunken driving has been charged in an alcohol-related crash that injured 10 people… (Greg)

Heiken, honored by the Illinois Department of Transportation’s traffic safety division in 2004 for making the most DUI arrests in Woodford County, faces up to three years in prison and could lose his job if convicted of the felony aggravated DUI charge…

Heiken admitted drinking at the Par-A-Dice, but refused blood-alcohol testing, according to the affidavit. Blood was taken against his wishes because people were injured in the accident, but test results were not available.

Funny how judges and cops have one righteous standard for the public, quite another for themselves.

What’s the Right Way to Give Field Sobriety Tests?

In most DUI investigations, the main evidence in determining whether there is probable cause to arrest is a battery of "field sobriety tests". Of course, if the officer administers the test incorrectly (as is commonly the case), the results are invalid — and an innocent person may be arrested.

So what is the correct way to give the tests and interpret them?

It's all laid out online (pdf) in the 165-page DWI Detection and Standardized Field Sobriety Testing Student Manual (2004 edition), published by the National Highway Traffic Safety Administration (USDOT) and widely used for training by law enforcement agencies nationwide. Read it and understand why few officers do it right.

(Thanks to Doug Hazelton.)

DUI “Eye Test” a Fraud?

The critical part of any pre-arrest investigation is the administration of the “field sobriety tests” (FSTs). These usually consist of a battery of excercises involving balance, coordination and mental agility — and are difficult to perform for even a sober person under ideal conditions (see “Field Sobriety Tests: Designed for Failure?”). Although there are many different tests (finger-to-nose, alphabet, etc.), an increasing number of law enforcement agencies are requiring their officers to use only the federally-recommended battery of three “standardized” FSTs.

The most recently developed of these is horizontal gaze nystagmus (HGN), commonly known as the “eye test”. It is particularly effective in trial not because of its accuracy, but rather because it appears to jurors as scientific in nature. As I have indicated in previous posts, however, HGN as a test for intoxication is fundamentally flawed and rarely understood or properly administered by police officers. (See “Nystagmus: The Eye Test”, “Nystagmus: The Eye Test (Part 2)”, and “Nystagmus: The Eye Test (Part 3)”.)

A study (Booker, 144(3) Science and Justice 133-139, 2004), has reviewed the scientific validity of the nystagmus test:

The Horizontal Gaze Nystagmus (HGN) test was conceived, developed and promulgated as a simple procedure for the determination of the blood alcohol concentration of drivers suspected of driving while intoxicated (DWI). Bypassing the usual scientific review process and touted through the good offices of the federal agency responsible for traffic safety, it was rushed into use as a law enforcement procedure, and was soon adopted and protected from scientific criticism by courts throughout the United States. In fact, research findings, training manuals and other relevant documents were often held as secrets by the state. Still, the protective certification of its practitioners and the immunity afforded by judicial notice failed to silence all the critics of this deeply flawed procedure….

In 1998 the integrity of the statistical evaluation of the original research upon which the validity of the tests rested was unfavorably reviewed [5]. In 2001 new research indicated that the Horizontal Gaze Nystagmus (HGN), the cornerstone of the test battery was fundamentally flawed and that the HGN test was improperly conducted by more than 95% of the police officers who used it to examine drivers suspected of driving while intoxicated (DWI) [6]. This summary critique demonstrates that it is scientifically meretricious and that the United States Department of Transportation indulged in deliberate fraud in order to mislead the law enforcement and legal communities into believing the test was scientifically meritorious and overvaluing its worth in the context of criminal evidence….

Deliberate fraud. Pretty strong language for a scholarly journal. After reviewing the flawed and deceptive justifications for using nystagmus in DUI investigations, the authors concluded that the test was essentially without scientific validity:

The state’s argument for the field sobriety tests does not rest on proof of merit, but upon qui tacet consentit reasoning ‘ that those tests have been so widely accepted they must have been subjected to some kind of review prior to adoption in the many jurisdictions where they are used, that somewhere along the way someone would have spotted the flaws and shortcomings. Considering that the student manual was originally considered to be a confidential state document and was only obtained through an ‘Open Records Act’ request, silence from the scientific community cannot be considered an endorsement of the program.