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This article is a continuation of the earlier articles regarding Driving Under the Influence and the tests and requrements that police need before making an arrest.  I left off the previous article on the Nystagmus tests and the things an officer will be looking for when conducting these tests.


I left off wiht step Six

here is step 7.

Check the right and left eye for the "Distinct and Sustained Nystagmus at Maximum Deviation clue"

If the jerkiness is distinct and sustained that is one clue.

Once again the position the stimulas approximately 12-15 inches in front of the subjects nose and slightly above eye level. 

Move the sitmulas off to the right side (checking the subjects left eye) untle the eyes have gone as far as possible

Hold the stimulas steady at that position for a minumum of fourt (4) seconds, and carefully watch eye. 

Then move the stimulas back across the subjects face all the way out to the left side.  (subjects right eye)

Hold the stimulas steady steady and carefully watch they eye. 

If the person is impaired, they eye is likely to exhibit definite, distinct and sustained jerking when hield at maximum deviation for a minumum of four seconds.  In order to "count" this clue as evidence of impairment, the nystagmus must be distinct and sustained for a minimum of four seconds. 

each eyes should be checked twice for this clue. 


The jerking of the eyes that occurs when they are brought out as far to the side as possible.  Most unimpared people people exhibit Endpoint Nystagmus.


This type of Nystagmus may occur if a persons eyes are held at maximum deviation for more than 30 seconds. 

Step 8 Onset of Nystagmus prior to 45 degrees. 

The stimulus is a positioned approximately 12-15 inches from the subjects nose and slightly above eye level.  It is necessary to move the stimulas slowly to identify the point at which the eye begins to jerk. 

Start moving the stimulus towards the right side (left eye) at a speed that would take approximtely 4 seconds for the stimulus to reach the edge of the subjects shoulder. 

As you slowly move the stimulus, watch the eye carefully for any sign of jerking.  When you see the jerking begin, immediately stop moving the stimulus and hold it steady at that posiiton. 

With the stimulus held steady look at the eye and verify that the jerking is continuing.  If the jerking is not evident with the stimulus held steady you have not located the point of onset.  Therefore, resume moving the stimulus slowly toward the side until you notice the jerking begin.

When you locate the point of onset Nystagmus you must determine whether it is prior to 45 degrees. 

Veriy that some white is still moving in the corner of the eye.

Examine the aglignment between the stimulus and the edge of the subjects shoulder.

Repeat the process of the subjects right eye. 

Each eye should be checked twice for this clue.

Step 9 total the clues

Maximum number of clues possible for each eye: 3

Total Maximum number of clues possible for both eyes 6. 

Step 10.  Check for vertical Nystagmus

Postion the stimulus horizontally about 12-15 inches in front of the subjects nose. 

Instruct the subject to hold the head still, and follow the eobject with the eyes only. 

Raise the object until the subjects eyes are elevated as far as possible

Hold for a minimum of four seconds. 

Watch closely  for evidence of they eyes jerking upward. 

For VGN to be recorded.  It must be distinct and sustained for a minimum of four seconds at maximum elevation. 

VGN may be present in subjects under the influence of high doses of alcohol for that individual or some other drugs. 

This article will be continued  

This article is a continuation of earlier articles that have went through DUI arrest from the time of the pullover until the time of the arrest and further.

earlier we went through the pullover some ot the signs of a person being under the influence and some of the objective symptoms. 

Also, we touched on the preliminary test and the non standardized versus standardized testing.  we continue that below.

ONSET OF NYSTAGMUS PRIOR TO 45 DEGREES (CLUE NUMBER THREE) This clue is present if a person eyes start to jerk before they reach 45 degrees.  Officers are trained to estimate 45 degrees two different ways. 

Using 15 square template that is cut diagnally.

Approximately equel to the edge of a person's shoulders

DRE qeustions using formula to prove BAC between .00 and .05%

Officers are trained that the three Standardized Field Sobriety elements are as followed:

1. Standardized Administrative Procedures

2. Standardized Clues

3. Standardized Criteria


Stanndardized Field Sobriety Tests Setup Questions.



Step 1 Check for eyeglasses Instruct subject to remove eyeglasses

Step 2 Vertical Instructions

put feet together hands at the side

keep the head still

look for stimulas

follow movement of the stimulas with eyes only

keep looking for the stimulas until the test is over

Step 3 Position the stimulas Position the stimulas approximately 12-15 inches in front of the subjects nose and slightly above eye level to commence the test


Resting Nystagmus may be observed at the time.  Officers should note whether the subject displays Resting Nystagmus.

Step 4 Equel Pupil Size and Resting Nystagmus.

Step 5 Check for equel tracking.  The speed of the stimulas should be approximately same speed used as checking for the lack of smooth pursuit.  Make at least two complete passes in front of the eyes. There should be at least two complete passes in front of the eyes.  There should be a clear distinguishable break between the check for equel tracking and lack of smooth pursuit.

If a person has unequel pupil size resting nystagmus or unequel tracking it suggests the person is likely to have medical conditions or injuries that would cause nystagmus to be present.  Some seizure medications also cause nystgmus. 

If  a person has an obvious eye condition such as an artificial eye. the HGN test should not be administered. 


It is necessary to move the object smoothly in order to check the eyes ability to pusue smoothly. the stimulas should be moved from center postiion.  all the way back across the subjects face all the way out to the left side where the eye can go no further (checking the subjects right eye) and then go back to the center. 

The object must be moved steadily at a speed that takes approximately 2 seconds to bring eye from center to side. 

In checking this clue make at least two complete passes in front of they eyes. 


Check the right and left eye for the "Distinct and Sustained Nystagmus at Maximum Deviation" clue.  If the jerkiness is distinct and sustained  that is one clue.


Next blog post we will continue on the factors that the officer must take into consideration before making an arrest for Driving Under the influence after that blog post we will take a break from the factors in determining whether to arrest for DUI and will look at other issues in the law including Not Guilty by reason of Insanity Law.

I will continue on today with some of the factors to consider in a dui case, and some of the test the police use.  I  will continue with some of the test the police will use to determine if there is probable cause to arrest somoene for DUI. 


NYSTAGMUS is closely related to rotational nystagmus when the person stops spinning, the fluid in the inner ear remains disturbed for a period of time, and the eyes continue to jerk.  This could be observed in a person after a rollover accident.  or spin out.



occurs when a foreign fluid such as alchol that alters the specific gravity of the blood in unequel concentrations in the blood and the vesitbular system.  This  causes the vestibular system to respond to gravity in certain positions, resulting in nystagmus.


PAN I occurs when the inner ear alcohol concentration in the blood is greater than the inner fluid.  PAN occurs while the BAC is increasing. 

PAN II occurs when the alcohol concentration in the inner ear.  This occurs while the BAC is decreasing. 



Optokinetic Nystagmus occurs when the eyes fixate on an object that suddenly moves out of sight, or when the eyes watch sharply contrasting moving images.


Examples include watching strobe strobe lights, rotating lights, or rapidly moving traffic.

Physiosocial Nystagmus is a natural nystagmus that keeps the sensory cells of the eye from tiring.  This is the most common type of Nystagmus this produces extremely minor jerks of the eyes. 

Natural Nystagmus

Gaze Nystagmus is a form of nystagmus that occurs when the eyes attempt to maintain visual fixation on a stimulas. Horizontal, vertical, and resting nystagmus are three forms.

Pathological Disorders

Nystagmus can also be caused by patholigical disorders.  They include brain tumors and other brain damage and some diseases of the inner ear. 


Certain medical conditions may also cause nystagmus to be present. 

Officers are trained to look for a total of six clues on the HGN test.  The officer looks for the same three clues in each eye.  If four or more clues are observed the test meet the criterion and or is a failure of the test.


A look of smooth pursuit clue number one.  this clue is present if the eyes jerk or bounce as they follow smoothly moving stimulas.

Distinct and sustained nystagmus at maximum deveation clue number 2 this clue is evident if the eye is held at maximum deviation of four seconds and continues to jerk toward the side some people exhibit jerking of the eye at maximum deviation even they are not imparied. 

Difference between Distinct Nystagmus and Distinct and Sustained Nystagmus at Maximum Deviation Questions. 

In the next article I will continue wiht a discussion of the tests to determine if someone is unde the influence while driving.

This article is a continuence of my earlier articles on Driving Under the Influence offense in Fresno ca and other parts of California.  As a Former Probation Officer DA and a Criminal Defense Attorney with more than 14 years of experience I have the knowlege to properly represent you in your criminal case or DUI case.  I have both the experience of prosecuting and defending DUI cases.  If after reading this blog bost or others you need help don't hesitate to call 559 441-1418. 

  In my earlier blog post I went over the non standardized testing to determine if there is probable cause to arrest for a Driving Under the Infuence. 


When an officer asks a driver to exit a vehicle, the officer is trained to look for the following additional specific signs of impairment.


unusual instructions

cant open the door

leaves car in gear

climbs out car

leans against car

keeps hands on car


Officers administer the three psychological field sobriety tests.  Psychological tests are methods of assessing a persons mental (psychological) and physical impairment.  Most psychological tests use the concept of divided attention to assess a persons impairment. 

Field sobriety tests that simulate the divided attention characteristics of driving have been developed and are being used by law enforcement agencies nationwide. 

These tests attempt to simulate the same mental and physical capabilities that a person needs to drive safely. 

information processing

short term memory

judgment and decision making


steady sure reactions

clear vision

small muscle control

coordination of limbs



The three Standardized Field Sobriety Tests tha tthe police use are the Horizontal Gaze Nystagmus (HGN) test, the Walk and Turn Test, and the One Leg Stand Test. 

The Horizontal Gaze Nystagmus test is administered first.  This test is considered to be the most reliable of the three standardized tests the police are  trained to do.  The police are trained that it is 77 percent accurate for people above the level of .10. 

Nystagmus is defined by the involuntary jerking of the eyes.  Nystagmus is a natural and and normal phenomenon.  Alcohol and certain drugs do not cause this effect.  They merely exaggerate or or magnify the effect. 

There are over 40 different kinds of Nystagmus and many of them look the same as the Horizontal Gaze Nystagmus that the police are looking for as evidence of impairment.

The police are not trained to distinguish between different kinds of Nystagmus.  However, some officers will testify that they are. 

it is common for the officer to misdiagnose some other form of bystagmus.  Call it Horizontal Gaze Nystagmus, and use it as evidence against a  person.


There are three general categories of Nystagmus:



Pathological Disorders and Disease. 

Vestibular Nystagmus

Vestibular Nystagmus is caused by the movement of or action of the vestibular (inner ear)  system. 

Rotational Nystagmus occurs when a person is spun around or rotated rapidly, causing the fluid in the inner ear to be disturbed.  If it were possible to observe eyes of a rotating person, they would be seen to jerk noticeably. 


Post rotational

nystagmus is a closely related to rotational nystagmus when the person stops spinning the fluid in the inner ear remains disturbed for a period of time. , and the eyes continue to jerk.  This could be observed in a person after a rollover accident or a spin out. 


nystagmus occurs when the fluid motion in the cannals of the vesibular system is stimulated by temperature (cold in one ear and warm in another). 

positional alcohol nystagmus (pan) occurs when a foreign fluid such as alcohol that alters the specific gravity of the blood is unequel concentrations in the blood and vestibular systems. 


This article will be an extension of the earlier articles that I have written regarding DUI's.  At the Law office of Gerald Schwab.  I represent People not cases the reason I do this job is to help people get through what could possibly be the worse days of there lives.  After being arrested you will have many questions you need experienced counsel.  I have both prosecuted and defended DUI case in Fresno and severl other couties including Madera, Fresno, Tulare, Merced, Monterey, and many more.

With a DUI case the main thing you are looking at is wether the proper paperwork and procedure was used, for the DUI arrest. 



To gain evidence, officers are trained to use three questioning tactics while the driver is still behind the wheel.  These tactics are:

1. Asking for two things simeltaneously

2. Asking interrupting or distracting questions

3. Asking unusual questions


These tactics are based upon the concept of divided attention.  They require the driver to concentrate on two or more things at the same time.  When an officer asks for two things simultaneously he might ask the driver to produce both his drivers license and the vehicle registration. 

The officer is then trained to look for the following evidence of impairmen

forgets to produce both documents

produces documents other than the ones requested

fails to see the license, registration or both while securing them

fumbles or drops the wallet, purse, license, or registration

is unable to retrieve documents within fingertips.


When an officer asks interrupting or distracting questions he might attempt to divide the drivers attention between searching for the license or registration and answering a new question. 

While the driver is responding to the request for license registration or both you ask unrelated questions "What days is it" or "Where are you coming from"

The officer is then trained to look for the following evidence of impairment. 

ignoring the question and concentrates only on license or registration search

forgets to resume the search after answering question

supplies a grossly incorrect answer

When an officer asks unusual qeustions it is employed after you have obtained the drivers license and registration

For example while holding the drivers license the officer might ask what is  your middle  name. 

There are many such questions which the driver mormally would be able answer quickly and easily but which might prove difficult if the driver is impaired, simply because they are unusual questions. 


For example a driver may respond to the question about the middle name by giving a first name.


There are three non-standardized sobriety test that an officer may ask a driver to perform prior to performing the standardized field sobriety test. 

Alphabet the driver is required to recite part of the alphabet.  The driver is instructed to begin with a letter other than A and stop at a letter other than Z.  This divides the drivers attention becuase he must concentrate to begin at an unusual starting point and remember where to stop. 

Count Down

The driver is asked to count out loud 15 or more numbers in reverse sequence.  For example, the driver might be told to "count out loud backwards.  Starting with the number 68 and ending with the number 53. 

Finger Count

The driver is asked to touch the the tip of the thumb to the tip of each finger on the same hand while simeltaneously counting up to one two three four then to reverse the direction on the fingers while simaltaneously counting down four three two one this is another divided attention task

I will continue in my next post on this subject.

As per my earlier article  I will be continuing my discussion of Drving Under the Influence law in Fresn Ca, and elsewhere in California. 

If you were arrested for Driving Under the Influence give our office a call and we can help you I have both prosecuted and defended DUI cases and have been in practice for more than 14 years.  

As stated in earlier article most DUI procedures are supposed to be the same for all states and all police so that the standards are not different.  Therefore, there are some common things to look for

PHASE One the pullover or why was I pulled over.

Officers are trained to observe the vehicle in operation and nota ny initial cues of a possible DUI violation.

Officers are trained that drivers that are impaired often exhibit certain effects or symptoms of impairment.  These include:

slowed reactions.

impaired judgements/willingness to take risks

impaired vision

poor coordination

The National Highway Traffic Administration sponsored research to identify the most common and reliable initial driving indicators of DUI

This research identifified 24 cues, each with an associated high probability that the driver exhibiting the cue is impaired. 

1. Weaving

2. Weaving across lane lines

3. Drifting

4. Straddling a lane line

5. Swerving.

6. Almost striking object or vehicle.

7. Turning with a wide radius

8. Stopping problems (to far, to short, to jerky)

9. Unnecessary acceleration or deceleration

10. Varying speed

11. 10 miles an hour or more below the speed limit.

12. Driving with headlights on at night

13. Failure to signal or signal inconsistant with action

14. Driving in opposing lanes or wrong way on one way.

15. Slow response to traffic signals.

16. Slow response to traffic signals

17. Stopping in a lane for no apparent reason

18. Following to closely

19. Improper or unsafe lane changes.

20. Illegal or improper turn.

21. Driving on other than designated roadway

22. Stopping innapropriately in response to officer

23. Innapropriate or unusual behavior (throwing objects, aruging, etc.)

24. Appearing to be impaired.



Driving is a task that requires your attention to be divided into sub tasks. 


controlling accelerator


controlling break pedal.

operating the clutch (if applicable)

observing other traffic

observing signal lights, stop signs, other traffic control devices,

making decisions (whether to stop, turn, speed up, slow down, etc

many other things

Divided Attention means concentrating on more than one thing at a time.

When a driver is under the influence of alcohol and/or drugs his ability to divide attention becomes impaired.  This inability to divide attention causes drivers to exhibit the 24 driving cues that police look for. 


The second task for the officer during phase one is to observe the manner in which the response to the signal to stop and to note any additional evidence of DUI violation. 

During this phase the officer is trained to look for the following

1. tries to flee

2. no response

3. slow response

4. abrupt swerve

5. sudden stop

6. strikes curb

7. new violations



The officer attempts to gather evidence of impairment by observing and interviewing the driver.  The officer may also ask the driver to perform non standardized test prior to him asking the driver to perform standardized testing. 

Officers are trained to use sight, hearing, and sense of smell to note additional evidence during there observation and interview of the driver. 

Officers look for the following specific signs of impairment. 

bloodshot eyes

soiled clothing

fumbling fingers

alcohol containers.

drugs or drug paraphanalia

bruises bumps or scrapes

slurred speech

admission of drinking

inconsistant responses

unusual statements

To gain evidence officers are trained to use three questioning tactics while the driver is still in the vehicle.  these three are

1. asking for two things simultaneously

2. asking interrupting or distracting questions

3. asking unusual questions.

These tactics are based on the concepts of divided attention.  They require the driver to concentrate two or more things at the same time.


I will further go into DUI arrest in a later post please give me a call if you have questions.





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Gerald Schwab, Jr.


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