Understanding the Standardized Field Sobriety Checks in Drunk Driving Cases

June 11, 2019

All way too often in the entire world of legal protection drunk driver illustration, lawyers who do not concentrate in drunk driving protection will consider on winnable ingesting and driving cases and advise their clients to plead responsible. In several cases, the purpose for this poor tips is based mostly on an faulty interpretation of the police report created by the arresting officer. Contained within the report will certainly be the officer’s rendition of the client’s efficiency of the officer’s area sobriety assessments. Realizing and knowing the science driving the standardized exams, as properly as the validity of the assessments is essential to a profitable defense for your shopper accused of drinking and driving.


The United States Govt, through the National Highway Targeted traffic Safety Administration (NHTSA) has sponsored a variety of studies and educational analysis to produce a uniform and fairly basic signifies to determine intoxication by way of a performance of assessments. The purpose of this sponsorship was to offer law enforcement officers investigating drunk driving instances the ability to establish, as properly as evidence, whether or not or not a drinking and driving suspect was under the affect of liquor. The final results of these initiatives are the “Standardized Field Sobriety Tests,” generally acknowledged as SFST’s.

The SFTS’s consist of three distinct actual physical assessments, which taken with each other are alleged to present a large chance that an individual’s blood alcoholic beverages content is in excess of the lawful limit. Especially, these exams contain the Stroll and Switch, 1-Leg Stand, and Horizontal Gaze Nystagmus Check.


The Horizontal Gaze Nystagmus (HGN) Check is the check which the officer places his or her finger in front of the suspect’s eyes and waives them close to. Regrettably for many drunk driving defendants, their attorneys do not realize how the officer is meant to correctly carry out the take a look at, nor do they understand what the officer is looking for. Nystagmus is an abnormal jerky motion of the eye. There is some questionable academic literature which finds that folks with blood alcoholic beverages levels over the lawful limit will have the presence of nystagmus in their eyes.

Prior to the functionality of the test, the officer is essential to check out for “equal tracking” of the eyes by moving their finger or another object quickly throughout the encounter of the drunk driving suspect. Equivalent tracking means that the eyes have to go in uniform and at the identical velocity. Next, the officer is needed to verify to make confident the drinking and driving suspect’s pupils are of equal measurement. Finally, the officer is necessary to request inquiries to the suspect with regards to getting any ailments which may possibly outcome in a false positive on the HGN check.

The genuine HGN take a look at is then carried out. The take a look at by itself is made up of a 6 stage method in which three distinct exams are done on every single eye, and if the sum of unsuccessful checks equals four or a lot more details, the suspect is considered to have unsuccessful the examination. Right here are the exams as follows:

Absence OF Sleek PURSUIT – The officer moves the object little by little but steadily from the center of the subject’s confront in the direction of the left ear. The left eye need to effortlessly comply with the item, but if the eye reveals nystagmus, the officer notes the clue. The officer then checks the correct eye.

Unique NYSTAGMUS AT Maximum DEVIATION – Starting once more from the middle of the suspect’s experience, the officer moves the object toward the still left ear, bringing the eye as far more than as feasible, and retains the object there for 4 seconds. The officer notes the clue if there is a distinctive and sustained nystagmus at this position. The officer holds the item at maximum deviation for at minimum four seconds to make sure that rapid motion of the item did not possibly lead to the nystagmus. The officer then checks the proper eye. This is also referred to as “conclude-point” nystagmus.

ANGLE OF ONSET OF NYSTAGMUS PRIOR TO FORTY-5 Degrees – The officer moves the item at a speed that would get about four seconds for the item to attain the edge of the suspect’s left shoulder. The officer notes this clue if the stage or angle at which the eye starts to exhibit nystagmus is just before the item reaches forty-5 degrees from the middle of the suspect’s confront. The officer then moves the object in direction of the suspect’s right shoulder. For safety factors, regulation enforcement officers generally use no apparatus to estimate the forty-5 degree angle. Generally, forty-5 levels from heart is at the point where the item is in front of the tip of the subject’s shoulder.

THE One particular-LEG STAND

In the A single-Leg Stand test, the impaired driving suspect is instructed to stand with 1 foot around six inches off the ground and count aloud by 1000’s (A single thousand-one, one particular thousand-two, and so on.) until finally instructed to place the foot down. The officer times the topic for 30 seconds. Harris County DWI Case Lawyer appears for 4 indicators of impairment, which includes swaying while balancing, using arms to equilibrium, hopping to sustain balance, and putting the foot down.

Walk AND Switch Test

In the Walk and Flip examination, the DUI subject is directed to consider 9 methods, heel-to-toe, together a straight line. Soon after taking the actions, the suspect need to flip on one foot and return in the same method in the reverse path. The police officer is essential to search for eight indicators of impairment: if the suspect can’t keep equilibrium while listening to the recommendations, begins before the recommendations are finished, stops although going for walks to get back stability, does not touch heel-to-toe, methods off the line, employs arms to stability, can make an inappropriate change, or normally takes an incorrect variety of methods.

Demanding THE OFFICER’S Conclusions OF THE SUSPECT’S FAILURE TO Effectively Complete THE Exams

It is really common for a criminal legal professional to receive a law enforcement report that implies that the defendant failed a single or more of the subject sobriety checks. A effectively skilled prison law firm familiar with drunk driving defense will right away check out whether the officer properly documented the SFST’s in the report. For instance, it is schedule that the officer in executing the HGN test will simply notice on the report that the defendant failed the check. What the report is silent on is exactly what actions of the HGN evaluation did the defendant fail, which factors of failure were attributed to which eye, was the pretest program followed, and so forth…… Recognizing these issues will enable the legal lawyer to crush the officer’s credibility regarding the SFST’s at the drunk driving trial.

Utilizing THE Video clip OF THE Cease TO THE DEFENDANT’S Edge

With any luck , the defendant has been billed in a jurisdiction the place the law enforcement equip their cars with cameras which record the cease and administration of the SFST’s. Watching and comprehending the movie is an absolute necessity to appropriately defending the dunk diving situation. More, the video clip will let the viewing, regardless of whether it is the protection legal professional or the jury, to see whether or not the officer truly comported with the NHTSA discipline sobriety examination needs. Possibilities are, the officer unsuccessful to appropriately administer one or more of the exams, a simple fact which ought to be reiterated in excess of and above to the jury.

IF THE SFST’S ARE Incorrectly Done

A significant problem that arises in a lot of drunk driving circumstances is that the officer fails to perform a single or more of the SFST’s or that exams are not correctly performed. A qualified legal protection legal professional must acknowledge that if this is the circumstance, a motion to suppress based on the ruling of Daubert v Merrell Dow Pharmaceuticals, Inc., 509 US 579 (1993) as effectively as their possess State’s interpretation of Federal Rules of Evidence 702. Generally, the argument is that the SFST’s are not scientifically valid if done incorrectly. In get to be done correctly, all three SFST’s must be performed precisely as explained by the NHTSA.


Although the officers associated in any drinking and driving investigation should have been skilled to use the a few SFST’s, for reasons unknown, officers utilize additional tests for the duration of the training course of the investigation in purchase to bolster the allegations that the drunk driving suspect is intoxicated. For instance, officers will use every thing from requiring the suspect communicate the alphabet to forcing the stating of the months of the calendar year. It is really essential that the defendant’s legal lawyer recognize that these assessments have little to no scientific foundation and need to not be allowed into proof at the demo. As with incorrectly performed SFST’s, non-standardized exams ought to be excluded for each the Daubert and FRE 702 investigation.