ZAVALA BECERRA & ASSOCIATES

CRIMINAL DEFENSE LAW FIRM

DRUNK DRIVING

  

COMMON DUI ARREST SCENARIO


 You go out with some friends, have a few drinks and decide you are sober and not under the influence of alcohol. You make the decision to drive home. Chances are, you are correct. The fact is that most people arrested for drunk driving are actually not impaired by alcohol.

 

Often, a dishonest police officer will pull someone over simply because they just came out of a bar. The dishonest cop will falsely write in his report that he saw the driver swerving in his lane, making unsafe lane changes or speeding.You know you are sober and you know you have done nothing wrong. But the cop has pulled you over for no reason and has asks if you had anything to drink. Regardless of your answer, he orders you to step out of the vehicle. Now you know that this cop has made up his mind you are guilty of drunk driving. He gives you a series of field sobriety tests and you pass them with flying colors. Regardless, he tells you to blow into a machine and when you ask him what the results where, he tells you to turn around and then places you under arrest.

 

CALCULATE YOUR ALCOHOL LEVEL HERE

 

 

MOST COMMON SOURCES OF ERROR 

 

Hand held instruments are known as "preliminary breath testers" (PBT), and their results.

Breath testers can be very sensitive to temperature, for example, and will give false readings if not adjusted or recalibrated to account for ambient or surrounding air temperatures. The temperature of the subject is also very important.

Breathing pattern can also significantly affect breath test results.  Holding one's breath for 30 seconds can increase the breath test result by about 28%.

Some breath analysis machines assume a hematocrit (cell volume of blood) of 47%. However, hematocrit values range from 42 to 52% in men and from 37 to 47% in women. A person with a lower hematocrit will have a falsely high BAC reading.

Research indicates that breath tests can vary at least 15% from actual blood alcohol concentration. An estimated 23% of individuals tested will have a BAC reading higher than their true BAC.

 

Calibration

 

Calibration is the process of checking and adjusting the internal settings of a breathalyzer by comparing and adjusting its test results to a known alcohol standard. Law enforcement breathalyzers are meticulously maintained and re-calibrated frequently to ensure accuracy.

There are two methods of calibrating a precision fuel cell breathalyzer, the Wet Bath and the Dry Gas method. Each method requires specialized equipment and factory trained technicians. It is not a procedure that can be conducted by untrained users or without the proper equipment.

The Dry-Gas Method utilizes a portable calibration standard which is a precise mixture of alcohol and inert nitrogen available in a pressurized canister. Initial equipment costs are less than alternative methods and the steps required are fewer. The equipment is also portable allowing calibrations to be done when and where required.

The Wet Bath Method utilizes an alcohol/water standard in a precise specialized alcohol concentration, contained and delivered in specialized simulator equipment. Wet bath apparatus has a higher initial cost and is not intended to be portable. The standard must be fresh and replaced regularly.

 

Interfering Compounds

 

Some natural and volatile interfering compounds do exist, however. For example, the National Highway Traffic Safety Administration (NHTSA) has found that dieters and diabetics may have acetone levels hundreds or even thousand of times higher than those in others. Acetone is one of the many substances that can be falsely identified as ethyl alcohol by some breath machines. However, fuel cell based systems are non-responsive to substances like acetone.

A study in Spain showed that metered-dose inhalers (MDIs) used in asthma treatment are also a cause of false positives in breath machines.

Substances in the environment can also lead to false BAC readings.  Any number of other products found in the environment or workplace can also cause erroneous BAC results. These include compounds found in lacquer, paint remover, celluloid, gasoline, and cleaning fluids, especially ethers, alcohols, and other volatile compounds.

 

Homeostatic Variables

 

Breathalyzers assume that the subject being tested has a 2100-to-1 partition ratio in converting alcohol measured in the breath to estimates of alcohol in the blood. If the instrument estimates the BAC, then it measures weight of alcohol to volume of breath, so it will effectively measure grams of alcohol per 2100 ml of breath given. This measure is in direct proportion to the amount of grams of alcohol to every 100 ml of blood. Therefore, there is a 2100-to-1 ratio of alcohol in blood to alcohol in breath. However, this assumed partition ratio varies from 1300:1 to 3100:1 or wider among individuals and within a given individual over time. Assuming a true (and US legal) blood-alcohol concentration of .07%, for example, a person with a partition ratio of 1500:1 would have a breath test reading of .10%—over the legal limit.

Most individuals do, in fact, have a 2100-to-1 partition ratio in accordance with William Henry's law, which states that when the water solution of a volatile compound is brought into equilibrium with air, there is a fixed ratio between the concentration of the compound in air and its concentration in water. This ratio is constant at a given temperature. The human body is 37 degrees Celsius on average. Breath leaves the mouth at a temperature of 34 degrees Celsius. Alcohol in the body obeys Henry's Law as it is a volatile compound and diffuses in body water. To ensure that variables such as fever and hypothermia could not be pointed out to influence the results in a way that was harmful to the accused, the instrument is calibrated at a ratio of 2100:1, underestimating by 9 percent. In order for a person running a fever to significantly overestimate, he would have to have a fever that would likely see the subject in the hospital rather than driving in the first place. Studies suggest that about 1.8% of the population have a partition ratio below 2100:1. Thus, a machine using a 2100-to-1 ratio could actually overestimate the BAC. As much as 14% of the population has a partition ratio above 2100, thus causing the machine to under-report the BAC.

Further, the assumption that the test subject's partition ratio will be average—that there will be 2100 parts in the blood for every part in the breath—means that accurate analysis of a given individual's blood alcohol by measuring breath alcohol is difficult, as the ratio varies considerably.

Variance in how much one breathes out can also give false readings, usually low. This is due to biological variance in breath alcohol concentration as a function of the volume of air in the lungs, an example of a factor which interferes with the liquid-gas equilibrium assumed by the devices. The presence of volatile components is another example of this; mixtures of volatile compounds can be more volatile than their components, which can create artificially high levels of ethanol (or other) vapors relative to the normal biological blood/breath alcohol equilibrium.

 

Mouth Alcohol

 

One of the most common causes of falsely high breathalyzer readings is the existence of mouth alcohol. In analyzing a subject's breath sample, the breathalyzer's internal computer is making the assumption that the alcohol in the breath sample came from alveolar air—that is, air exhaled from deep within the lungs. However, alcohol may have come from the mouth, throat or stomach for a number of reasons. To help guard against mouth-alcohol contamination, certified breath-test operators are trained to observe a test subject carefully for at least 15–20 minutes before administering the test.

The problem with mouth alcohol being analyzed by the breathalyzer is that it was not absorbed through the stomach and intestines and passed through the blood to the lungs. In other words, the machine's computer is mistakenly applying the partition ratio (see above) and multiplying the result. Consequently, a very tiny amount of alcohol from the mouth, throat or stomach can have a significant impact on the breath-alcohol reading.

Other than recent drinking, the most common source of mouth alcohol is from belching or burping. This causes the liquids and/or gases from the stomach—including any alcohol—to rise up into the soft tissue of the esophagus and oral cavity, where it will stay until it has dissipated. The American Medical Association concludes in its Manual for Chemical Tests for Intoxication (1959): "True reactions with alcohol in expired breath from sources other than the alveolar air (eructation, regurgitation, vomiting) will, of course, vitiate the breath alcohol results." For this reason, police officers are supposed to keep a DUI suspect under observation for at least 15 minutes prior to administering a breath test. Instruments such as the Intoxilyzer 5000 also feature a "slope" parameter. This parameter detects any decrease in alcohol concentration of 0.006 g per 210 L of breath in 0.6 second, a condition indicative of residual mouth alcohol, and will result in an "invalid sample" warning to the operator, notifying the operator of the presence of the residual mouth alcohol. PBT's, however, feature no such safeguard.

Acid reflux, or gastroesophageal reflux disease, can greatly exacerbate the mouth-alcohol problem. The stomach is normally separated from the throat by a valve, but when this valve becomes herniated, there is nothing to stop the liquid contents in the stomach from rising and permeating the esophagus and mouth. The contents—including any alcohol—are then later exhaled into the breathalyzer.

Mouth alcohol can also be created in other ways. Dentures, for example, will trap alcohol. Periodental disease can also create pockets in the gums which will contain the alcohol for longer periods. Also known to produce false results due to residual alcohol in the mouth is passionate kissing with an intoxicated person. Recent use of mouthwash or breath freshener—possibly to disguise the smell of alcohol when being pulled over by police—contain fairly high levels of alcohol.

 

Testing During Absorptive Phase

 

Absorption of alcohol continues for anywhere from 20 minutes (on an empty stomach) to two-and-one-half hours (on a full stomach) after the last consumption. Peak absorption generally occurs within an hour. During the initial absorptive phase, the distribution of alcohol throughout the body is not uniform. Uniformity of distribution, called equilibrium, occurs just as absorption completes. In other words, some parts of the body will have a higher blood alcohol content (BAC) than others. One aspect of the non-uniformity before absorption is complete is that the BAC in arterial blood will be higher than in venous blood. Laws generally require blood samples to be venous.

During the initial absorption phase, arterial blood alcohol concentrations are higher than venous. After absorption, venous blood is higher. This is especially true with bolus dosing. With additional doses of alcohol, the body can reach a sustained equilibrium when absorption and elimination are proportional, calculating a general absorption rate of 0.02/drink and a general elimination rate of 0.015/hour. (One drink is equal to 1.5 ounces of liquor, 12 ounces of beer, or 5 ounces of wine.)

Breath alcohol is a representation of the equilibrium of alcohol concentration as the blood gases (alcohol) pass from the (arterial) blood into the lungs to be expired in the breath. The venous blood picks up oxygen for distribution throughout the body. Breath alcohol concentrations are generally lower than blood alcohol concentrations, because a true representation of blood alcohol concentration is only possible if the lungs were able to completely deflate. Vitreous (eye) fluid provides the most accurate account of blood alcohol concentrations.

 

Retrograde Extrapolation

 

The breathalyzer test is usually administered at a police station, commonly an hour or more after the arrest. Although this gives the BrAC at the time of the test, it does not by itself answer the question of what it was at the time of driving. The prosecution typically provides an estimated alcohol concentration at the time of driving utilizing retrograde extrapolation, presented by expert opinion. This involves projecting back in time to estimate the BrAC level at the time of driving, by applying the physiological properties of absorption and elimination rates in the human body.

Extrapolation is calculated using five factors and a general elimination rate of 0.015/hour.

For example: Time of breath test-10:00pm...Result of breath test-0.080...Time of driving-9:00pm (stopped by officer)...Time of last drink-8:00pm...Last food-12:00pm

Using these facts, an expert can say the person's last drink was consumed on an empty stomach, which means absorption of the last drink (at 8:00) was complete within one hour-9:00. At the time of the stop, the driver is fully absorbed. The test result of 0.080 was at 10:00. So the one hour of elimination that has occurred since the stop is added in, making 0.080+0.015=0.095 the approximate breath alcohol concentration at the time of the stop.

 

BASIC DRUNK DRIVING OFFENSES

 

The breath alcohol content reading is used in criminal prosecutions in two ways. The operator of a vehicle whose reading indicates a BrAC over the legal limit for driving will be charged with having committed an illegal per se offense: that is, it is automatically illegal throughout the United States to drive a vehicle with a BrAC of 0.08 or higher. The breathalyzer reading will be offered as evidence of that crime, although the issue is what the BrAC was at the time of driving rather than at the time of the test.

The suspect will also be charged with driving under the influence of alcohol (sometimes referred to as driving or operating while intoxicated). While BrAC tests are not necessary to prove a defendant was under the influence, the law requires the jury to presume that he was under the influence if his BrAC is found and believed to be over 0.08 (grams of alcohol/210 liters breath) when driving. This is a rebuttable presumption, however: the jury can disregard the test if they find it unreliable or if other evidence establishes a reasonable doubt.

 

Vehicle Code Section 23152(a)

Per SeVeh. C.23152 is the non-injury drunk driving statute. Non-injury drunk driving is usually referred to as misdemeanor drunk driving.

Subdivision (a) of 23152 makes it illegal to drive, a vehicle, while under the influence of alcohol.

 

Vehicle Code Section 23152 (b): D.U.I. Alcohol; 0.08%

Subdivision (b), the so called; per se statute, makes it illegal to drive, a vehicle, with a blood or breath alcohol concentration (B.A.C.) of 0.08% or more. Subdivision (b) was first added to the Vehicle Code in 1982.

 

A Comparison of Subdivisions (a) and (b)

 

The difference between subdivisions (a) and (b) of 23152 is that evidence of alcohol is necessary for a conviction of violating subdivision (a), whereas under subdivision (b), only blood or breath alcohol concentration need be proved. In cases where there is no chemical test result, only (a) is charged because alcohol level is difficult to determine on the basis of impairment evidence alone. Since some people are under the influence at alcohol levels as low as 0.05%, chemical test evidence indicating a blood or breath alcohol level of 0.08% or more would probably be necessary for there to be legally sufficient evidence of violation of subdivision (b) (cf., Wheeler v. D.M.V. (1997) 34 CA4th 228, 28 CR2d 597 [fn 6 ).

In most cases with chemical test results both (a) and (b) will be charged, but judgment of conviction can only be entered on one of them (People v. Duarte (1984) 161 CA3d 438, 207 CR 615). Both of the drunk driving offense statutes (Veh. C. 23152 and 23153) require that the defendant drive a motor vehicle.

 

But what acts constitute driving?

 

Where the defendant was seen operating a moving automobile on a highway there is almost never any controversy about whether or not he was driving the vehicle. But occasionally the arresting officer hasn't seen any such acts which are indisputably driving. Instead he has perhaps found the defendant asleep on the front seat of a vehicle which is legally parked, with the transmission in neutral, the headlights and wipers on, and the engine running.

In Mercer v. D.M.V. (1991) 53 C3d 753, 280 CR 745, 49 CrL (BNA) 1191, the California Supreme Court held that mere actual physical control is not enough to constitute driving. Thus, for the purpose of the drunk driving statutes, requires volitional movement of the vehicle.

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