DWI Attorney Houston, Texas
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With over fifty years of combined aggressive DWI defense experience our family operated, nationally recognized DWI criminal defense attorneys are dedicated to providing you with high-quality solutions using innovative DWI criminal defense.

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In order to successfully prosecute a person accused of DWI, the State must prove beyond a reasonable doubt each element of the DWI offense. In other words the State must prove:

  1. a person;
  2. operated;
  3. a motor vehicle;
  4. in a public place;
  5. while;
  6. intoxicated.

Each element of the offense has its own set of unique issues.  Below is an explanation of issues and holes that your DWI Houston Attorney will look to magnify in defending your DWI case.

“The Person”

The person element comes into play if identity is at issue. Typically, this involves evidence the accused was not the driver or insufficient proof the accused was the person who committed the offense of DWI.

It is the State’s burden to offer evidence and identify the accused as the driver. Courts have held the State failed to meet this burden where the accused was only seen exiting the driver’s side after a single car accident. On the other hand, courts have held the State met its burden where an officer testified he saw the accused switch seats with the passenger.

The “Operating” Element:

Most DWIs occur after an officer has observed a traffic violation.  This situation makes the element of operating relatively easy to for the State to prove.  However, there are situations where the vehicle was never observed driving on the road.  A single car accident is such an example.  In these instances, the State still has to prove operating and getting there isn’t as ‘cut and dry’ as your routine traffic violation.

How have the Courts defined operating?

Courts have defined operating as “functioning the vehicle in a manner that would enable the vehicle’s use.”  Operating, in a DWI context, can exist if the vehicle never moves.

Examples of operating:

  • driver asleep in driver’s seat + engine running + vehicle in gear + only thing keeping the vehicle from moving was curb.
  • driver asleep in driver’s seat + engine running + vehicle in drive + foot on brake
  • witnesses observed person rev the engine + spin tires + car never moved.

What if no one observed you operating or driving?

This is typically the case regarding single vehicle accidents.  In such an instance the State must provide independent evidence regarding when the vehicle was operated or driven (e.g. how recently the vehicle had been driven; or how much time had elapsed between the accident and the arrival of the police officers).

If the State is unable to pin down the time of the accident or the time the accused drove in a public place, the evidence is insufficient to prove the operating while intoxicated element.  Your DWI Attorney will move the court for an instructed verdict of acquittal.

What if no one observed you driving, but you confess that you drove?

Your confession alone is not sufficient to prove you were DWI.   The State must bring corroborating evidence that you did in fact drive.  Corroborating evidence includes such things as title and ownership of vehicle, proof of registration, warmth of hood upon police arrival, etc.

The operating element, depending on the facts of the case, can provide a “pit-fall” for the State.  If they are unable to prove the necessary elements, the case should be dismissed.

“Public Place”

Under the law a public place is essentially any place to which the public has access to (i.e. streets, highways, office buildings, apartment houses, etc.).

Areas determined to be a public place include:

a parking lot;
a gated community;
a closed city park;
a military base;
a marina;
a college campus.

Areas Determined NOT to be a public place include:

an unpaved driveway or a rural residence;
yard of a private residence.

“Motor Vehicle”

Pretty self-explanatory, but a motor vehicle includes:

watercraft (Boating While Intoxicated).

The “Intoxicated” Element

Intoxication is defined as either:

1) Not having the normal use of mental or physical faculties by reason of the introduction of alcohol or drugs (also known as the impairment theory); or
2) having an alcohol concentration of 0.08 or more (also known as the per se theory).

Under the impairment theory the State must prove beyond a reasonable doubt that the accused has loss the normal use of mental or physical faculties. The State does not have to prove the accused lost the use of his/her specific normal/physical faculties. In other words, the State need not prove what is normal for the accused. However, your DWI criminal defense lawyer may present evidence the accused could not use his/her mental/physical faculties in a normal manner due to some reason other than intoxication (i.e. illness, injury, fatigue, weight, etc.).

The “While” Element

The majority of DWIs today include either a breath or blood test.

The test result measures the blood alcohol content (BAC) at the time of test. In order to obtain a conviction the State must prove the BAC was 0.08 or higher at the time of driving (under the per se definition of DWI).

Back to the Future – Retrograde Extrapolation

To accomplish this difficult feat, the State uses an expert to testify about Retrograde Extrapolation. Retrograde Extrapolation is, simply, going back in time. However, there is nothing simple about taking a single known BAC and connecting it to a previous known time. The State, in a manual published by the Department of Public Safety, acknowledges this problem admitting the alcohol concentration at the time of arrest could be the same, higher, or lower than the time of test. This is in large part because absorption and eliminate rates vary in persons and can be affected by a number of factors (e.g. if and when you ate food).

When is Retrograde Extrapolation Admissible in Court?

Courts have held retrograde extrapolation is scientific evidence, despite much criticism from the leaders in the scientific community. As scientific evidence in order for it to be relevant, reliable, and admissible the State must show: the underlying scientific theory to be valid; the technique applying the theory to be valid; and the technique properly applied on the occasion in question.

The State’s Expert should be able to: apply and explain the theory with clarity; explain the difficulties associated with the theory; demonstrate awareness of the risks associated with the theory; and clearly and consistently apply the theory. Additional factors, at a minimum, should also be considered, such as: the length of time between the offense (driving) and the test; number of tests given; known characteristics of the accused (e.g. person’s weight; gender; typical drinking patterns; tolerance; how much the person had to drink; what the person drank; what time the person began drinking; what time the person stopped drinking; how much and what the person had to eat).

If the State cannot meet the requirements above, testimony regarding what the BAC may have been at the time of driving, your DWI defense attorney should argue the results are inadmissible. While the State may still pursue the DWI under the impairment theory (i.e. loss of normal and mental faculties), their ability to prosecute under the per se theory (0.08+) may be significantly limited.

So when the officer is asking you questions about what you drank, how long you drank, time you drank, what you ate, time you ate, etc. he or she is gathering evidence against you. Evidence to be used by the State in the form of retrograde extrapolation.