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What Are Common Mistakes Police Make in a DWI Arrest?

Common mistakes police make in a DWI arrest are the key to a strong DWI defense.  Police must follow a strict set of procedures when gathering evidence. However, police often break this protocol. In most cases, failure to meet protocol standards is unintentional. These common police mistakes can be your best chance at a dismissal.

If an arresting officer commits an error gathering evidence, it cannot be used in court. A criminal defense attorney will file a motion to suppress. After that,  the evidence will be thrown out of court if a judge approves. In other words, without any evidence you can avoid a DWI conviction.

Improper Traffic Stop

This is the most common mistake. Above all, police can not pull you over based on intuition. In order to stop you, police in Texas need to have “reasonable suspicion“. Reasonable suspicion requires the officer have specific and articulable facts of a crime. In other words, they need to observe driving behaviors consistent with an inebriated motorist.

Reasonable suspicion includes:

  • Weaving
  • Erratic or excessive speed
  • Stopping in a traffic lane
  • Failing to signal
  • Driving on something other than the roadway
  • Near collisions
  • Sleeping on the side of the road or parking lot
  • Unsafe behavior or vehicle code infraction

A stop without reasonable suspicion is improper. As a result, the judge will dismiss the case against you.

Improper Arrest

An officer can pull you over for DWI based on reasonable suspicion, but probable cause must exist for an arrest. This is a higher standard of proof. That is to say, they must be able to gather enough evidence that would lead a reasonable person would believe the driver was inebriated.

Probably cause includes:

  • Smell of alcohol
  • Slurred speech
  • Breathalyzer results
  • Standardized field sobriety test results

An arrest without probable cause is improper. As a result, the judge will dismiss the case against you.

Improper Standardized Field Sobriety Testing (SFST)

Standardized field sobriety tests exist as a way for police to determine probably cause for an arrest. These tests consist of:

  • One-leg stand (OLS)
  • Walk & turn (WAT)
  • Horizontal Gaze Nystagmus (HGN)

Failing these tests will lead to an arrest. However, the reliability of SFSTs is debatable. In addition, the results are invalid if the officer:

  • Fails to follow testing standards.
  • Provides inaccurate instructions.
  • Cannot provide accurate and detailed documentation about the performance of each test.

Incorrect field testing will render any evidence collected inadmissible in court.

Improper Breathalyzer Testing

Breathalyzer accuracy is questionable. Similarly, there are many outside factors that create false positives. In addition, results are inadmissible if protocol is not met:

  • Operator certification – The operator must be certified. In addition, that certification must be annually renewed .
  • Procedure – Protocol must be followed. For instance, a police officer must wait 15 minutes before a breath test is administered.
  • Machine maintenance & certification – The machine must be certified and periodic maintenance must be performed.
  • Machine calibration – An improperly calibrated machine will provide false or unverifiable readings.

Incorrect breath testing will render any evidence collected inadmissible in court.

Improperly Conducted Blood Tests

While blood tests are considered a higher level of proof, they are not admissible in court if procedures are not followed. These include:

  • The arrest must be valid. In other words, without reasonable suspicion or probable cause, results are inadmissible in court.
  • Police must have driver consent or a warrant, unless implied consent applies.
  • Blood must be drawn by a professional. For example, only a physician, qualified technician, chemist, registered professional nurse or licensed vocational nurse can withdraw the blood samples in the officer’s presence.
  • Blood samples must be properly stored to prevent fermentation. For instance, samples cannot be left in a trunk for a week.
  • All participants must follow and document chain of custody.

Incorrect blood testing will render any evidence collected inadmissible in court.

Call Houston DWI Lawyer Clyde W. Burleson, P.C.

In conclusion, hiring a lawyer who knows the mistakes police make in DWI arrests is essential for your DWI defense. Most importantly, call 713-628-1503 and get a free case consultation from Clyde Burleson.


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