Widmark Calculations in a California DUI Attorney's Jury Trial

In the previous San Diego California DUI Lawyer article, it was noted extrapolation of and from BACs or levels in the body has been around since Widmark developed equations in the 1930's.

California DUI lawyers face BAC calculations usually during the direct examination of the California DUI’s prosecution’s expert. Based upon Widmark BAC calculations, the California DUI prosecution’s expert will usually expediently claim that what the California DUI attorney’s client told the police officer he or she had to drink on the night in question cannot possibly be true. The California Prosecution’s Drunk Driving expert will maintain that Widmark’s formula proves the California DUI attorney’s client must have had much more alcohol to drink than the California DUI attorney’s client told the California DUI officer.

The California DUI Prosecution expert will finally opine that whatever the actual chemical test results were, the California DUI lawyer’s client’s actual blood alcohol level at the time of driving was higher than at the time of the California Drunk Driving chemical test.

During the attack on the prosecution expert’s Widmark calculations, the California DUI defense lawyer may usually count on obtaining information helpful in the California DUI attorney’s case. An opportunity for a California DUI arrestee to prevail in a California DUI trial comes out during the reasonable attack on Widmark calculations. Widmark calculations in California DUI breath testing cases sometimes results in evidence unfavorable to the advocating California Drunk Driving prosecutor.
A main reason Widmark calculations are offered in a California DUI trial is that California has a statute prohibiting a person from having a certain amount of alcohol in the blood at a proscribed time. The .08% BAC California law is known as the “per se” California DUI law.

The proscribed time in the California DUI per se law is the time when the person was driving a motor vehicle. But California Drunk Driving chemical tests are not performed at the actual time the vehicle was being driven by the California DUI attorney’s client. California DUI prosecutors believe it is necessary to try to establish a numerical blood alcohol value for the time covered by the California DUI per se law. This process of obtaining a numerical blood alcohol level for a time prior to the blood test is generally done by the use of Widmark calculations or a modified variation of Widmark’s formula.

California’s per se Vehicle Code section 23152(b)’s statute prohibits driving with .08 percent or more of alcohol in a person’s blood:
It is unlawful for any person who has 0 .08 percent or more, by weight, of alcohol in his or her blood to drive a vehicle.

The more a California DUI criminal defense lawyer can shake jurors loose from a general predisposition of guilt (the predominant problem in a California drunk driving trial), the more favorable the trial prospects of the California DUI defense attorney’s mission to accomplish justice through an acquittal.

Attacking Widmark calculations is an effective way to accomplish this mission because the Widmark formula uses averages to arrive at conclusions in California Drunk Driving cases. Most reasonable California jurors understand the problems inherent with using averages, and averages are the antithesis of proving something beyond a reasonable doubt. When California jurors hear that there is going to be a calculation using a long established formula, most jurors presume that the calculation is going to have some type of mathematical certainty. But when the jurors hear that in reality the Widmark calculations are actually nothing more than an educated guess, they will begin to question some of their initial assumptions.

After the California DUI defense lawyer’s cross-examination on Widmark calculations many jurors may not be as predisposed to convict as when they were first seated. Part of the California DUI defense from the start is to get jurors to think there is more to this than I first thought or the case is not so cut and dried. One way to remind jurors about the problems with averages that are used in Widmark calculations is to give them analogies that emphasize the problem with using averages. A premier California DUI attorney might tell jurors if one leg on a person’s slacks is too short, and one leg is too long - the California DUI prosecution’s tailor would have you believe that on average the slack’s fit just fine. Or, if when you first turn the shower on in the morning, the water is very cold, and then it turns to extremely hot, don’t worry - on average according to the California DUI prosecution’s plumber you are having a nice shower.

With the aid of a calculator, a paid California DUI Prosecution expert has determined that the accused had a high BAC. This opinion cements the jurors’ first impressions that the California DUI attorney’s client is in fact guilty. But the way that these Widmark computations are presented provides a unique opportunity for a California DUI defense attorney: simply ask the state’s expert if he or she discussed the case with the prosecutor before testifying. The answer is usually “yes.” The California DUI attorney then asks if the two of them discussed the calculations determining the number of drinks the California DUI attorney’s client consumed. The answer is usually “yes.”

Confirm the fact that the California DUI Prosecution expert knew the answer to the prosecutor’s drink calculation question before it was asked. The state’s expert witness and the California DUI prosecutor are exposed. Why is the California DUI prosecution lawyer going to such lengths to deceive California jurors? A predominant problem for the California DUI defense attorney begins to become solved.
Next ask what Erik Matteo Prochet Widmark’s formula is.
The formula is found in Widmark’s 1932 treatise, Die theoretischen Grundlagen und die praktische Verwendbarkeit der gerichtlich – medizinischen Alkoholbestimmung (Principles and Applications Medicolegal Alcohol Determination).

California DUI Prosecution experts often do not really have an expert understanding of Widmark’s work. They presume that they can get away with making Widmark calculations without discussing the limitations in the calculations, and usually they do. A California DUI lawyer can expose imposters posing as experts on Widmark. Ask the expert if there was some formula the expert used to calculate the amount of drinks the expert claims the California DUI attorney’s client drank. The expert will usually say there is such a formula. Ask if the formula used was the Widmark formula. The expert will say yes, or will say a modified version of the formula based on Widmark’s work was used.

When asked what the Widmark formula is, many California DUI Prosecution experts will testify to a formula that is not the actual formula. These experts, instead use a shorthand version of the formula in court. This shorthand version of the formula does not accommodate any of the variables that are in the actual formula. [See DUI Law History.] A California DUI defense lawyer may ask the expert what the actual Widmark equation is. The answer is often that the expert does not know. A California DUI defense attorney will then emphasize in closing that the state’s expert made calculations without knowing the actual formula.
There are a number of California DUI Prosecution experts who have not read Widmark’s work. When a California DUI attorney asks such an “expert” if he or she has read Widmark’s work, they often reply that they have not read it because the work is in German. But California DUI lawyers often point out there is an excellent English translation of the work by Randy C. Baselt, Ph.D. California DUI attorneys may ask an ultimate question: “Have you even read the book?” This maximizes the impact of their failure to read the definitive work. If the expert does not know the actual formula, and has not even read the book, the strength of the expert’s opinions and calculations will be diminished.

There are two key variables in the Widmark formula: the ß factor and the r factor. An important thing for lawyers to know about variables is that the numbers are not constant for all people. [See Assumptions ] But the shorthand formulas that the California DUI prosecution’s experts typically use assume constant variables for all people. [See Retrograde Extrapolation] These formulas assume that the California DUI attorney’s client has an average r factor, and an average ß factor [See DUI Law History] The California DUI prosecution criminalist ends up making an educated guess about the California DUI attorney’s client’s drinking. This would not be so wrong if the California DUI prosecution’s expert admitted to the California DUI attorney that his or her calculations were based on assumptions. But this is rarely done, and when it is done it is given only a passing reference. It is up to the California DUI defense attorney to explain to the jury the whole truth behind these tainted California DUI Prosection expert’s calculations.

In a California DUI breath test case, if the state’s expert states that the California DUI attorney’s client is not telling the truth based on Widmark calculations, the defense should consider arguing that the prosecution has opened the proverbial door to tell the jury the truth about breath machines and partition ratios. The California DUI attorney’s client has a constitutional right to cross-examine witnesses. The witness is calling the California DUI attorney’s client a liar, but it may be that it is really the machine that is lying. [See Scientific Variations, Blood Alcohol Content, Dr. Hlastalas Breath Test Case Analysis, Pointer v. Texas, 380 U.S. 400, 404 (1965) ]

A California DUI defense attorney should be able to show the right to tell the jury the truth that the California DUI attorney’s client was not lying when he told the officer what he or she had to drink on the night in question? [See Unfair]
A California DUI defense lawyer should argue that to protect the California DUI attorney’s client from false claims made by the prosecution’s expert about the California DUI attorney’s client’s veracity, the California DUI attorney’s client has a federal constitutional right to tell the jury the truth about breath machines, partition ratios and Widmark calculations. [See Breath Test Reliability ]
In a California DUI breath case, if the prosecution’s expert claims that based upon the expert’s calculations the California DUI attorney’s client must by lying, the door to partition ratios has been thrust open in California DUI cases. [See California DUI Criminal Defense]