of DUI Cases
are several defenses and strategies that are typically
relevant depending on the facts of your case. Not all
will apply and we will be able to refine your exact
defense as we accomplish more of the tasks in the investigation
stage. However, I will describe below some of these
The DUI prosecutor will point to several factors as
evidence that you were drunk driving: poor navigation
of your vehicle, an odor of alcohol flowing from the
breath, the appearance of being intoxicated, poor performance
on the field sobriety test and, of course, the results
of the blood or breath alcohol test. Yet each "piece
of DUI evidence" is ambiguous, subject to multiple
interpretations, unreliable, based on faulty assumptions
and open to attack.
Contrary to popular belief, DUI cases do not rest on
hard science. They rest on pseudo-science, often times
Unfortunately, hundreds of innocent people get convicted
of DUI every court day, often by pleading guilty even
in the face of spurious prosecution evidence. Hopefully,
you won’t be one of them.
1. GERD Or Heartburn
Caused A Falsely High Reading On The DUI Breath Alcohol
Suffering from Gastroesophageal Reflux Disease (GERD),
acid reflux or heartburn can "fool" the DUI
breath machines, causing an inaccurately high reading
of the blood alcohol level.
The breath machine is supposed to receive and measure
alcohol from the deep lung tissue, a region of the lungs
called the alveoli. Breath alcohol concentration (BAC)
from this "alveolar air" or "deep lung
air" is thought to correlate with blood alcohol
But GERD can cause alcohol to travel from the stomach
back to the throat and mouth. When this happens, the
DUI suspect blows this "mouth alcohol" (rather
than alveolar air alcohol) into the breath machine.
The machine then provides a reading higher, often times
dramatically higher, than the DUI suspect’s true
BAC. A person with a true BAC of .05 can read .20.
This problem is not limited to those who suffer from
regular or chronic GERD. Anyone who recently ate a large
meal, a greasy meal or a spicy meal may experience acid
reflux or heartburn. If you take a DUI breath test during
this period, the results may be erroneously high.
2. The DUI Police Officer
Failed To Read You Your Miranda Rights
Police must advise you of your Miranda Rights in a DUI
case if (1) you are in custody and (2) they question
you seeking to elicit an incriminating response. If
the officers continued to interrogate you after placing
you in custody for DUI, and did not first read you your
Miranda rights and obtain a valid waiver, then your
post-custodial statements will likely be excluded from
3. Weaving Within Your
Lane Does Not Justify A DUI Traffic Stop
Many DUI traffic stops occur because the officer claims
to observe the DUI suspect weaving within his/her lane,
perhaps with the tires touching the fog line or yellow
lane divider, or briefly encroaching into the neighboring
lane. Courts have ruled that this usually does NOT justify
a DUI traffic stop—unless an "experienced
officer" observed "pronounced weaving"
for a "substantial distance." If the court
finds that your traffic stop was not justified, the
entire DUI case will most likely be dismissed.
4. Alcohol On Your
Breath Does NOT Mean The Driver Is Under the Influence
In explaining why he believes you were drunk, the DUI
officer almost always mentions smelling "a strong
odor of alcohol on the suspect’s breath."
But the officer looks foolish on cross-examination when
he admits that alcohol itself (ethanol) has no odor.
Rather, it’s the mixing agent or flavoring that
produces the odor we associate with alcohol. If you
doubt this, go to the market and buy a 6-pack of O’Doul’s.
It tastes and smells just like beer; but it contains
Indeed, laboratory studies show that police officers’
perceptions of how strongly a person’s breath
smells of alcohol simply doesn’t correlate with
his/her actual blood alcohol level. All that can be
gleaned from the "odor of alcohol on the breath"
is that a DUI suspect probably consumed some alcohol
recently. But it does not provide evidence that the
person drank enough to be "under the influence"
or to have a BAC .08 or higher.
5. The Officer Lacked
Probable Cause For The DUI Arrest
After conducting the roadside DUI investigation, the
officer can only arrest you (apply the handcuffs and
take you away for a chemical test) if he/she has "probable
cause." This means the evidence must rise to a
level in which a reasonable DUI officer would believe
a crime (drunk driving) has been committed.
You are entitled to a special court proceeding—called
a "suppression hearing" or "1538.5 hearing"—in
which a judge decides whether the DUI officer had probable
cause for the arrest. At the hearing, the officer testifies
and is cross-examined by the DUI defense lawyer.
Our firm conducts this hearing routinely in DUI cases.
If the judge decides the officer who arrested you for
DUI lacked probable cause probable cause, then the subsequent
breath or blood alcohol test is excluded from evidence.
Often, the entire case is dismissed.
In practice, judges usually side with the prosecution
at the suppression hearing, finding that probable cause
existed. Still, the hearing provides an invaluable opportunity
to question the officer and confront him/her about the
problems with the DUI investigation. This often leads
the prosecution to reduce the charge or to settle the
DUI case on terms more favorable to the defense.
6. There Are Innocent
Explanations For Your Faulty Driving
Perhaps the DUI officer saw you swerving for a short
distance, make a wide turn or drift out of your lane.
Of course he will paint these as sure signs of drunk
driving. But in reality, sober drivers engage in these
sorts of driving miscues all the time.
How often do you see a car drifting around in its lane,
only to look over and notice the driver on the cell
phone? Or reading a map? Or eating? Usually, the "bad
driving" the DUI officer claims to observe is just
as consistent with a distracted or inattentive driver—but
otherwise sober driver—as it is with a drunk driver.
7. The Alleged Signs
of DUI Are Actually Signs Of Fatigue
Many of the "typical" symptoms associated
with DUI can just as easily be explained by fatigue.
Sheer exhaustion often causes one to drive his/her vehicle
poorly, to have bloodshot and watery eyes, to respond
slowly to some of the DUI officer’s questions,
and to struggle with the field sobriety tests that require
vigilance and good coordination.
Obviously, driving while exhausted or drowsy is dangerous,
and should be avoided. But the symptoms of driving while
exhausted can easily be confused with the symptoms of
driving while intoxicated.
8. Your Blood Alcohol
Level Was Rising
A DUI suspect can blow a .15 at the police station;
but have had a .07 BAC when he got pulled over. Why?
Because alcohol takes an average of 50 minutes, but
can take as long as three hours, to absorb fully into
your bloodstream and create your peak blood alcohol
level. This is critical if the DUI traffic stop occurred
relatively soon after you finished drinking.
Your BAC was probably still rising. This means that
even if your BAC was above .08 when the blood draw or
breath test occurred at the police station (or hospital),
it may well have been below .08 when you were actually
driving. There is no law against having a BAC above
.08 at a police station; it’s only the blood alcohol
level while actually driving that counts for DUI purposes.
9. An Improper 15-Minute
Observation Before The Breath Alcohol Test
California regulations require the officer to watch
the DUI suspect continuously for at least 15 minutes
prior to administering the breath alcohol test. The
officer must make sure that during this period the person
does not consume anything, burp, belch, hiccup or regurgitate.
Any of these may cause alcohol to travel from the stomach
to the mouth. Blowing this "mouth alcohol"
into the breath machine triggers an inaccurate high
Officers rarely follow this required observation procedure.
They usually perform paperwork, write reports, set up
the machine and converse with their partners, diverting
their attention from the DUI suspect who must be watched
vigilantly during this period. Failure to follow this
procedure casts doubt on the validity of the test result,
and can sometimes get the test thrown out of court altogether.
10. The Police Officer
Lacked Justification To Make The DUI Traffic Stop
Police officers cannot pull you over arbitrarily. To
conduct a lawful traffic stop, the DUI officer must
provide "specific articulable facts" indicating
a "reasonable suspicion" that you were committing
a traffic violation. You are entitled to a special court
proceeding called a "suppression hearing"
where a judge determines whether the DUI officer can
meet this standard. If he cannot, in all likelihood
the entire DUI case will be dismissed.
11. Failure To Comply
With California’s Title 17 Regulations
California Code of Regulations Title 17 sets forth procedures
that must be followed by anyone administering DUI blood
or breath alcohol tests. Officers break these regulations
all the time in DUI investigations. A failure to follow
the regulations can expose the BAC test results to attack,
or lead to their exclusion from evidence altogether.
12. Inherent Error
Rate In DUI Blood and Breath Alcohol Testing
Let’s assume maintenance and calibration of the
machines are perfect, the breath or blood test is administered
exactly according to procedure, and no background or
physiological factors exist that would produce false
results (and, by the way, such a "perfect scenario"
An inherent error still exists as to both blood alcohol
testing procedures. Most experts agree the inherent
error rate is about +/- .02 for DUI breath testing and
+/- .005 for DUI blood testing.
13. The DUI Officer
Has No Baseline For Your Performance On The Field Sobriety
The DUI officer will probably claim you "performed
poorly" on the field sobriety tests, and that this
serves as evidence of impairment. But "poorly"
compared to what? This claim means very little without
knowing how you would perform normally—even with
nothing to drink. People vary tremendously in their
natural ability (or inability) to perform DUI field
How well a given person performs the filed sobriety
tests depends on many factors: natural level of coordination
and equilibrium, natural level of balance, fitness level,
composure in the face of pressure, injuries, age and
practice, among others.
14. Factors Other Than
Alcohol Can Cause Poor Performance on the Field Sobriety
Even if you performed less than perfectly on the DUI
field sobriety tests, this may be attributable to unfair
test conditions such as:
The tests occurring on uneven surfaces or slippery terrain
The distraction of flashing lights and traffic whizzing by
The test area being too dark or amidst glaring lights
Cold temperatures, rain, or wind
Unsuitable footwear—such as boots, high heels or dress shoes
Nervousness, anxiety and/or frustration
Most people who had nothing to drink would still struggle
with the FSTs under these conditions. The upshot is
this: even if you struggled on the roadside tests, this
may well be caused by the setting and circumstances
rather than you being intoxicated.
15. The DUI Standardized
Field Sobriety Tests Were Not Properly Administered
The National Highway Traffic Safety Administration (NHTSA)
devised national standards for how DUI officers are
to administer the three standardized field sobriety
tests: the Horizontal Gaze Nystagmus Test, the Walk-and-Turn
Test and the One-Leg Stand Test. But DUI officers often
fail to adhere to these national guidelines. Many never
even received training as to the NHTSA guidelines. This
opens up their whole DUI investigation to attack.
Sometimes a DUI officer will say in his report the DUI
suspect "failed" or "performed poorly"
on the field sobriety tests; but when the performance
is judged according to NHTSA’s national standards,
the person did everything correctly! This underscores
a basic fact of DUI defense: the arresting officers
are biased and frequently do slipshod DUI investigations.
Their claims and opinions should never be taken at face
16. The Non-Standardized
Field Sobriety Tests Lack Reliability
The non-standardized field sobriety tests include (among
others): the finger-to-nose test, the finger count test,
the hand pat test, the coin pickup, the alphabet test,
the reverse counting test, and the Rhomberg test (tilting
your head back and estimating 30 seconds). The National
Highway Traffic Safety Administration (NHTSA) has set
no standards for how to administer, score or interpret
these tests, and no studies have ever shown them to
be reliable indicators of DUI impairment.
17. Field Sobriety
Tests Provide a Poor Measure Of DUI Impairment
Even when the standardized field sobriety tests are
administered perfectly (which is rare), they still provide
a very inaccurate measure of whether a DUI suspect is
impaired. According to NHTSA, for example, the one leg
stand test has a 65% accuracy rate and the walk-and-turn
test a 68% accuracy rate.
This means that if people were convicted based on these
roadside tests, one third of them would be innocent
and wrongly convicted. Or, viewed another way, when
officers arrest DUI suspects based on failing these
tests, one in three suspects is wrongfully arrested.
18. Mouth Alcohol Can
Contaminate The Breath Alcohol Test Results
Ideally, DUI breath testing devices detect alveolar
air of the deep lungs, which is loosely correlated with
blood alcohol level. But the breath testing machine
can be "tricked" by latent alcohol in the
mouth—often caused by burping, belching, or the
recent use of cough syrup, cold medicine, mouthwash
or breath spray.
When the breath testing machine picks up mouth alcohol
rather than deep lung air, it gives BAC readings greatly
higher than the true BAC. This becomes a particular
problem for DUI arrestees with dentures, denture adhesives,
braces, cavities, food impactions, orthodontic work
or who have food particles trapped between their teeth
(as all of these conditions tend to produce mouth alcohol).
19. Blood-Breath Partition
Ratio Is Inaccurate Based on Individual Differences
DUI breath testing assumes that "breath alcohol"
accurately reflects blood alcohol based on a 2100-to-1
partition ratio. This assumption rests on the proposition
that the average ratio across the population is 2100-to-1.
But studies reveal that the ratio of blood to breath
varies greatly among individuals.
A DUI suspect with a ratio lower than 2100-to-1 will
generate an inaccurately high reading from a breath
alcohol test. And there’s no way to determine
what a given person’s ratio is, or what it was
at the time of the DUI breath test.
20. The Breath Alcohol
Test Yields Unduly High Results During Absorption
Breath alcohol testing while alcohol is still absorbing
into your bloodstream often yields falsely high BAC
readings. During the absorption stage, which can last
as long as three hours after you finish drinking, the
BAC in arterial blood is significantly higher—as
much as 60% higher—than the BAC in venous blood.
Because the alveolar deep-lung air blown into the breath
machine is bathed in arterial blood, not venous blood,
a falsely high BAC is generated.
21. Police Have No "Special
Ability" To Judge Intoxication Levels
Police and DUI prosecutors like to suggest that trained
and experienced officers have a "special ability"
to discern when a DUI suspect is under the influence
(and therefore jurors should defer to the officer’s
opinion that the DUI defendant was, in fact, impaired).
But a controlled study by Rutgers University’s
Alcohol Behavior Research Laboratory found otherwise.
Police officers’ ability to judge intoxication
levels was no more accurate than that of bartenders
or social drinkers. Moreover, none of the three groups—experienced
police officers, bartenders or social drinkers—correctly
judged levels of intoxication more than 25 percent of
22. No Sign Of Mental
Being "under the influence" consists of two
types of impairment: mental and physical. Most police
will admit that upon being pulled over, the DUI suspect
was coherent, alert and responded appropriately to the
officer’s questions. Therefore no sign of "mental
But, as any DUI toxicologists will tell you, "mental
impairment" always precedes "physical impairment."
So if mental impairment was not present, then, presumably,
neither mental nor physical impairment was present.
23. Innocent Explanations
For The Symptoms Of Intoxication
Police officers almost always claim to have observed
certain "objective symptoms of intoxication"
in the DUI suspect. The standard list includes:
Bloodshot and watery eyes
A flushed face
An unsteady gait
DUI police reports feature pre-printed boxes for these
symptoms that officers merely check off. Of course,
the officers almost never photograph, videotape or audiotape
the DUI suspect so that jurors can later judge for themselves
whether and to what extent these symptoms were present.
In any event, non-alcohol causes often explain these
observations. For example, fatigue, allergies and eye
strain cause bloodshot eyes. Nervousness, embarrassment
and anger over the DUI traffic stop cause flushing.
Intimidation and fluster cause slurred speech.
The officer rarely takes these innocent explanations
into account. The DUI defense attorney must emphasize
to the jury that the evidence is just as consistent
with non-alcohol explanations as it with intoxication.
24. Speeding Is Not
Correlated With DUI
In many of our DUI cases, the officer pulled the client
over for speeding. And the officer alleges the client
to be under the influence based (at least in part) on
the fact the client was speeding. But national studies
demonstrate no correlation between speeding and intoxication.
A speeding driver is no more likely to be drunk than
sober. To be sure, speeding is often unsafe and a violation
of the law; but it is not evidence the driver is DUI.
25. Radio Frequency
Interference May Have Contaminated Your BAC Tests
Radio waves in the air—known as Radio Frequency
Interference (or RFI)—can alter the results of
almost any DUI blood or breath alcohol testing device.
Radio Frequency Interference can disturb the electronic
circuitry of Los Angeles County’s Datamaster,
San Bernardino County’s Draeger Alcotest 7110,
gas chromatographs and mass spectrometers, thereby resulting
in inaccurate high blood alcohol readings.
Radio Frequency Interference emits from almost any electronic
device, including police radios, police scanners, radar
devices and computers. Although studies have confirmed
the danger of Radio Frequency Interference or electromagnetic
interference to render false BAC readings, it is difficult
to determine whether or to what extent RFI altered the
result in a given DUI case. Yet it is one more reason
26. Breath Testing
Machines Mistake Other Chemicals for Alcohol
DUI Breath alcohol testing machines also detect non-alcohol
compounds, which they frequently mistake for alcohol.
Among the compounds most commonly mistaken for alcohol
are ethylene, toluene, nitrous oxide, diethyl ether,
acetonitrile and isopropanol.
The presence of any of these compounds in the DUI suspect’s
lung tissue will likely cause a false, or falsely high,
blood alcohol reading. We find that people frequently
ingest these compounds at work or in other environments
where the chemicals are present.
27. Low-Carb Diets
Can Cause Falsely High DUI Breath Test Readings
A DUI suspect on a low-carb diet may generate an erroneously
high blood alcohol reading from the DUI breath testing
machines. On a high-protein diet, the body produces
ketosis as it burns stored body fat for energy (a process
that has produced dramatic weight loss for many adherers
to Adkins-style diets).
Consumption of carbohydrates (such as alcoholic beverages)
during ketosis can cause the body itself to produce
a substance called "isopropyl alcohol." Most
DUI breath testing machines cannot distinguish "isopropyl
alcohol" from ethanol (the alcohol that we drink
and that causes impairment).
28. Breathing Techniques
May Alter Breath Test Results
Breathing techniques may produce falsely high breath
test results. A longer breath sample—more than
10 seconds—may generate a significantly higher
BAC reading because the machinery is calibrated to test
a 10 second sample. Additionally, a person who breaths
shallow or holds her breath may blow residual mouth
alcohol, again producing a higher reading than her true
BAC. Hyperventilation may also impair the test.
29. Breath Temperature
May Alter Breath Test Results
Most DUI breath devices calibrate to test breath at
34 degrees C. Simulator solutions use the same temperature.
But when a DUI suspect’s breath temperature varies—as
is often the case — this can produce a falsely
high BAC result. Even a variation only one degree higher
can produce a BAC reading 7% higher.
30. A "Disconnect"
May Exist Between Your BAC And Symptoms Of Intoxication
Certain symptoms of intoxication can predictably be
observed at each successively higher blood alcohol level.
Often we see DUI cases where the person’s BAC
reading comes back very high, two or three times the
However, the person’s driving, behavior and FSTs
are consistent with sobriety or only slight impairment.
We know the BAC reading is wrong. It doesn’t match
the other evidence. We call this a "disconnect
case." Any time the alleged blood alcohol level
does not match up with the symptoms we would expect
to see at that level, the prosecution’s whole
DUI case is called into question.
31. Blood Tests Have
One of the most important concepts to emphasize at a
DUI trial where a blood test must be contested is that
the alcohol concentration in blood can go up over time
because of fermentation. In the same way that the sugar
in grapes ferments into wine, the sugar in potatoes
ferment into vodka, and the sugar in grains ferments
into beer, the sugar in blood - "blood sugar"
- can ferment into alcohol. That is why we will have
the blood sample re-tested and our lab will test for
this phenomenon and check for whether there was an adequate
amount of preservatives and anti-coagulant in the test
As noted before, the defense will depend on the facts
in your case and not all of the above will apply. I
would like to meet with you to go over each of the above
issues to develop your personal defense strategy.