DUI Lawyer | Joel Brand, Esq.

Most Common Mistakes Police Make at a DUI Stop

Being arrested for a DUI (Driving Under the Influence) can be a life-altering event, but it is important to understand that not all DUI arrests lead to convictions. Police officers must adhere to strict procedures when conducting DUI stops and arrests. If they fail to follow these procedures, it can lead to evidence being deemed inadmissible in court, which can ultimately result in the dismissal of your case. As a California DUI attorney, I have seen many cases where procedural errors made by law enforcement officers have been pivotal in securing a dismissal for my clients. In this article, we will explore the most common mistakes police officers make during DUI stops that can lead to your case being dismissed.

1. Lack of Reasonable Suspicion for the Stop

Legal Background

Under the Fourth Amendment of the U.S. Constitution, individuals are protected against unreasonable searches and seizures. For a traffic stop to be lawful, an officer must have reasonable suspicion that a crime or traffic violation has occurred. This principle is supported by the landmark case Terry v. Ohio, 392 U.S. 1 (1968).

Common Mistakes

  • No Traffic Violation: Officers sometimes pull over drivers without observing any traffic violation. For example, stopping a driver merely because they were leaving a bar is not sufficient grounds for a stop.
  • Profiling: If the stop was based on racial or other forms of profiling rather than specific, articulable facts, it is unlawful.

Impact on Your Case

If it can be demonstrated that the officer did not have reasonable suspicion for the stop, any evidence gathered as a result of the stop, including breathalyzer results and field sobriety tests, can be suppressed. This suppression often leads to the dismissal of the DUI charge.

2. Improper Administration of Field Sobriety Tests (FSTs)

Legal Background

Field Sobriety Tests are standardized tests developed by the National Highway Traffic Safety Administration (NHTSA) to assess a driver’s impairment. The three standardized tests are the Horizontal Gaze Nystagmus (HGN), the Walk-and-Turn, and the One-Leg Stand.

Common Mistakes

  • Improper Instructions: Officers must give clear and correct instructions. Failure to do so can result in inaccurate results.
  • Non-Standardized Tests: Using non-standardized tests or modifying standardized tests can lead to unreliable results.
  • Medical Conditions: Failing to account for medical conditions or disabilities that could affect performance on the tests.

Impact on Your Case

Evidence from improperly administered FSTs can be challenged in court. If the court finds that the tests were not conducted according to NHTSA standards, the results may be excluded from evidence, weakening the prosecution’s case.

3. Inaccurate Breathalyzer Calibration and Maintenance

Legal Background

Breathalyzers must be properly calibrated and maintained to ensure accurate readings. The California Code of Regulations, Title 17, sets forth the requirements for breathalyzer calibration and maintenance.

Common Mistakes

  • Failure to Calibrate: Not calibrating the device according to the specified schedule.
  • Improper Maintenance: Failing to maintain the device according to manufacturer specifications.
  • Operator Error: Officers not following the correct procedures for administering the test.

Impact on Your Case

If it can be shown that the breathalyzer was not properly calibrated or maintained, the accuracy of the test results can be called into question. This can lead to the breathalyzer evidence being excluded, which is often critical to the prosecution’s case.

4. Violation of Miranda Rights

Legal Background

Under Miranda v. Arizona, 384 U.S. 436 (1966), individuals in custody must be informed of their rights before interrogation. This includes the right to remain silent and the right to an attorney.

Common Mistakes

  • Failure to Read Rights: Not reading the Miranda rights to the suspect before questioning.
  • Coercive Interrogation: Using coercive tactics to elicit statements after the suspect has requested an attorney.

Impact on Your Case

Statements made by the defendant during a custodial interrogation without being informed of their Miranda rights can be suppressed. If these statements are critical to the prosecution’s case, their exclusion can lead to a dismissal.

5. Lack of Probable Cause for Arrest

Legal Background

To make a lawful arrest, an officer must have probable cause to believe that the individual has committed a crime. This standard is higher than reasonable suspicion and requires a reasonable belief, based on facts, that the person is guilty of the offense.

Common Mistakes

  • Insufficient Evidence: Arresting a driver without sufficient evidence of impairment.
  • Misinterpretation of Evidence: Misinterpreting the results of field sobriety tests or breathalyzer tests.

Impact on Your Case

If it can be demonstrated that the officer lacked probable cause for the arrest, any evidence obtained as a result of the arrest can be suppressed. This can severely undermine the prosecution’s case and lead to dismissal.

6. Mishandling Blood Samples

Legal Background

Blood tests must be conducted in accordance with strict guidelines to ensure accuracy. Title 17 of the California Code of Regulations specifies the procedures for collecting, storing, and analyzing blood samples.

Common Mistakes

  • Improper Collection: Not following proper procedures for collecting the blood sample.
  • Storage Issues: Failing to store the blood sample correctly, leading to contamination or degradation.
  • Chain of Custody Errors: Breaking the chain of custody, making it difficult to verify the sample’s integrity.

Impact on Your Case

Improper handling of blood samples can lead to questions about the accuracy and reliability of the blood test results. If these results are critical to the prosecution’s case, their exclusion can lead to a dismissal.

Conclusion

Understanding the most common mistakes that police officers make during DUI stops can be crucial for defending against DUI charges in California. Procedural errors, improper administration of tests, and violations of rights can all lead to evidence being suppressed, which can result in the dismissal of charges. If you have been charged with a DUI, it is important to work with an experienced DUI attorney who can identify these mistakes and use them to build a strong defense. By doing so, you can significantly increase your chances of a favorable outcome in your case.

Citations

  1. Terry v. Ohio, 392 U.S. 1 (1968).
  2. California Code of Regulations, Title 17.
  3. Miranda v. Arizona, 384 U.S. 436 (1966).
  4. National Highway Traffic Safety Administration (NHTSA) guidelines.