How Motions to Suppress Work in Texas DWI Cases

Driving While Intoxicated (DWI) cases often depend on the evidence that was gathered during a traffic stop and arrest. Police officers often rely on observations, field sobriety tests, breathalyzer tests, or blood tests to support a DWI charge. However, not all of the evidence that is collected during a DWI investigation is admissible in court.

When a law enforcement officer violates a driver's constitutional rights or fails to follow the proper procedures, the defense can ask the court to exclude incriminating evidence from the case. This is done through a specific type of legal tool known as a "motion to suppress."

In many Texas DWI cases, motions to suppress play an important role in determining if key evidence can be used by prosecutors. If important evidence is excluded, it can significantly weaken the case or even lead to the charges being dismissed.

Understanding how motions to suppress work in Texas DWI cases is important, especially for those who are facing these charges. The Texas DWI deferred adjudication guide can be helpful.

What Is a Motion to Suppress in a DWI Charge and Criminal Case

A motion to suppress is a formal legal request made by experienced criminal defense attorneys asking a judge to prevent specific evidence from being used in a criminal trial. The motion argues that the evidence was obtained in violation of the constitutional rights of the defendant or through improper procedures.

Motions to suppress are common in criminal cases that involve search, seizures, or statements made to police.

In DWI cases, suppression motions might focus on evidence that was obtained during the following:

• The initial traffic stop

• The roadside investigation

• The arrest itself

• Chemical testing procedures

If the judge looks at the situation and agrees that the evidence was improperly obtained, they can rule that it cannot be used in the court case.

The Constitutional Basis for Suppression Motions

Motions to suppress are often based on constitutional protections that limit how police officers conduct their investigations. One of the most important here is from the Fourth Amendment, which protects people from unreasonable search and seizure.

In a DWI arrest, this means that the police must have a valid reason for stopping the vehicle, detaining the driver, conducting a search, or making an arrest.

Another important part of the Constitution to consider is the Fifth Amendment. This protects people from being pushed to incriminate themselves during questioning.

If the defense counsel can prove that the officers violated these protections, they can ask the court to exclude the evidence from the prosecution's case.

The “Exclusionary Rule”

The legal doctrine behind motions to suppress is known as the exclusionary rule. This prevents prosecutors from using evidence that was obtained illegally.

The rule was established thanks to the Supreme Court, and the goal of the rule is to discourage unlawful conduct by police. Under this rule, courts can exclude the following:

• Physical evidence obtained through illegal searches

• Statements obtained in violation of constitutional rights

• Evidence derived from unlawful police actions

This idea is sometimes referred to as the "fruit of the poisonous tree" doctrine, meaning that evidence obtained from illegal search or other actions may also be excluded.

Common Reasons for Suppression Motions in Texas DWI Cases

In DWI cases, motions to suppress often challenge how the legality of the investigation. There are several types of issues that might arise:

Lack of Reasonable Suspicion for the Traffic Stop

Police officers must have reasonable suspicion that a traffic violation or criminal activity occurred before they stop the vehicle. The following is considered reasonable suspicion:

• Speeding or other traffic violations

• Swerving between lanes

• Driving without headlights at night

• Failing to obey traffic signals

If none of theses things happened, though, the officer may not have had a legal reason to stop the driver, and any evidence that was obtained could be suppressed.

Unlawful Detention

Even if a traffic stop is valid, the officer cannot detain an accused person for an extended amount of time without justification. For instance, once the officer completes the traffic stop, if they want to keep the suspect longer, they will require additional evidence. If they don't have that, it's very possible that the defense will file a motion to suppress.

Improper Administration of Field Sobriety Tests

Field sobriety tests are common in DWI cases, as they can assess a driver's level of coordination and cognitive function. These tests include:

• Horizontal Gaze Nystagmus (HGN)

• Walk-and-Turn

• One-Leg Stand

Police officers must give these tests in a certain way. If they are not done correctly, or they are done under unfavorable conditions, the results can be challenged and a motion to suppress may be filed.

Lack of Probable Cause for Arrest

Before a person can be arrested for DWI, the officer must have probable cause to believe the driver is intoxicated. Examples of probably cause include:

• Poor performance on field sobriety tests

• The smell of alcohol

• Slurred speech or physical impairment

• Admissions of drinking

If a person was arrested for DWI without enough evidence to establish probably cause, it is considered an unlawful arrest and the defense can ask the court to suppress DWI evidence. Sparks Law Firm has information on open container vs DWI in Texas as well.

Improper Breath or Blood Testing Procedures

Chemical tests are also often part of a DWI case, and many times, defense attorneys can suppress evidence here, too. Oftentimes its because law enforcement didn't use the correct procedure to obtain the test. For instance, a defense lawyer may attempt to suppress evidence if the following occurred:

• The officer used improperly calibrated breath-testing equipment

• They failed to follow testing protocols

• There were problems with blood sample collection or storage

• There was a lack of proper warrants in blood draw cases

If the court determines that these procedures were not followed correctly, the test results may be excluded from evidence.

How the Motion to Suppress Process Works

The process of filing and arguing a motion to suppress generally occurs before trial.

Step 1: Filing the Motion

The defense attorney files a written motion explaining why certain evidence should be excluded. The motion outlines the legal arguments and identifies the specific evidence being challenged.

Step 2: Suppression Hearing

The court may schedule a suppression hearing to examine the arguments. During this hearing:

• The prosecution presents evidence supporting the legality of the investigation.

• The defense challenges the lawfulness of police conduct.

Police officers involved in the arrest may testify about their actions and observations.

Step 3: Judicial Decision

After hearing the arguments, the judge decides whether the evidence should be admitted or suppressed.

If the judge grants the motion, the challenged evidence cannot be used at trial. If the motion is denied, the evidence remains admissible.

Why Motions to Suppress Can Be Important in DWI Cases

Prosecutors often rely heavily on the evidence that was gathered by police officers during traffic stops and field sobriety tests. When that evidence cannot be used, oftentimes, the prosecution loses the key parts of its case.

For instance, a motion to suppress may remove evidence like:

• Breathalyzer test results

• Field sobriety test evidence

• Statements made by the driver

• Observations obtained during unlawful detention

Without this evidence, the prosecution may have difficulty proving intoxication beyond a reasonable doubt.

Video Evidence and Suppression Hearings

Many modern DWI cases involve video evidence. This might come in the form of dashboard camera footage for from a police officer's body camera. These videos often play a very important role during the process to suppress evidence in a DWI case.

Video evidence may show the following:

• Whether the traffic stop appeared justified

• How field sobriety tests were administered

• Whether the driver was properly informed of their rights

• How long the driver was detained

Judges often rely on the footage available when making a decision on the motion to suppress evidence.

The Strategic Role of Suppression Motions

Motions to suppress are not simply procedural filings. They are often a key strategic component of a criminal defense.

Even if a motion is ultimately denied, the suppression hearing can provide valuable insight into the prosecution’s evidence and the testimony of law enforcement officers.

In some situations, the hearing may reveal inconsistencies in police reports or weaknesses in the investigation that can affect how the case proceeds.

Why Evidence Issues Matter in Texas DWI Cases

DWI charges in Texas are serious, and they often lead to fines, the suspension of the driver's license, probation, and even jail time in some cases. Because these cases are very dependent on evidence, the legality of how that evidence was obtained is important.

An experienced attorney will use motions to suppress as a legal tool to take a close look at the procedures that were used to obtain the evidence being used against their client. If the evidence was obtained in an unlawful way, the courts can exclude it to ensure a fair trial.

Sparks Law Firm is a Fort Worth-based criminal defense firm that is always working hard to protect their clients' rights. If you are facing DWI charges and believe evidence was obtained illegally, contact the firm for a free consultation.