Breath and Blood

Breath and Blood Tests in Dallas DWI Cases

Breath tests and blood tests are different types of evidence in a DWI case, and both can be challenged. A breath test estimates alcohol concentration by analyzing a person's breath, while a blood test measures alcohol and, depending on the testing performed, other substances in a blood sample.

A chemical test result is only one part of the evidence prosecutors may use in a Dallas DWI case. The State may also rely on the circumstances of the traffic stop, an officer's observations, field sobriety testing, body-camera footage, dashcam video, and statements made before or after an arrest.

Challenging a Breath Test

Breath-test evidence can raise questions about the equipment, testing procedure, and circumstances surrounding the test. Depending on the case, a Dallas DWI attorney may examine:

Whether the breath-testing equipment was properly maintained and functioning

Whether the officer was properly trained or certified

Whether required observation procedures were followed

Whether the required observation period was completed

Whether mouth alcohol or other factors could have affected the result

The timing of the breath test in relation to the alleged driving

A potential problem with one aspect of a breath test does not automatically mean the result is inadmissible or inaccurate. The significance of an issue depends on the evidence and applicable Texas law.

Challenging Blood Test Evidence

Blood testing can involve a different set of legal and scientific issues. Depending on the circumstances, the defense may examine whether law enforcement had legal authority to obtain the blood sample, whether a warrant was properly issued and executed when required, and whether the collection and handling procedures complied with applicable requirements.

The defense may also review:

How and when the blood sample was collected

How the sample was labeled and preserved

Who handled the sample before testing

Whether proper chain-of-custody procedures were followed

The laboratory's testing methods and records

Whether the laboratory equipment and procedures were reliable

Whether the reported concentration accurately reflects the sample at the relevant time

Why Timing Matters in a DWI Test

The timing of a breath or blood test can be important. A chemical test performed after a person has stopped driving does not necessarily show exactly what the person's alcohol concentration was at the moment of driving.

Alcohol concentration can change over time, and the significance of a test result depends on the circumstances surrounding the test. For that reason, a Dallas DWI defense may consider the timing of the alleged driving, the arrest, the collection of the sample, and the administration of the test rather than examining the test result in isolation.

The Criminal Case and License Suspension

A Dallas DWI arrest can create two separate legal matters: the criminal DWI prosecution and the administrative driver's license suspension process.

The criminal case determines whether the State can prove the DWI charge. The administrative process can determine whether the driver's license should be suspended following the arrest. These proceedings have different rules, procedures, and deadlines.

One important deadline can arise shortly after the arrest. In many cases, a person has 15 days from receiving the applicable notice to request an Administrative License Revocation (ALR) hearing. Missing the applicable deadline can affect the person's ability to challenge the proposed suspension.

Why Early DWI Defense Matters

A DWI investigation can generate important evidence, including police reports, body-camera footage, dashcam video, field sobriety test information, breath-test records, blood-test documentation, laboratory data, and other records.

Early legal review can help identify what evidence exists, preserve potentially important records, and determine whether there are legal, procedural, scientific, or factual issues that could affect the case.

If you are facing a DWI charge in Dallas, the consequences can include potential jail time, fines, driver's license consequences, increased insurance costs, and other long-term effects. A Dallas DWI lawyer can review the chemical testing evidence alongside the traffic stop, arrest, officer observations, and other circumstances to develop a defense based on the specific facts of your case.

Dallas DWI Lawyers

325 North St Paul Street, Suite 3100, Dallas, TX, 75201

(945) 403-4331

https://www.DallasTXDWILawyers.com/