San Antonio DWI Defense Lawyer

Challenging a DWI in Texas

The challenges to a DWI focus broadly on two areas—the legitimacy of administering the BAC level test to begin with, and the accuracy of the reading the test produces. That is, did the officer have the legal right to take the blood or breath specimen?  

The broader question is whether the laboratory analyst properly followed the Standard Operating Procedures, and if there were errors were they properly noted and corrected?  Erroneous laboratory procedures including hardware or software error must be identified and corrected or retest of the blood will be required.  The analyst tries his/her best not to retest, but in some instances it is mandatory.

All of the following are issues that our San Antonio DWI attorney can investigate:

• Did the police officer have reasonable suspicion to pull the car over? A police officer can’t randomly pull drivers over, they need a reason. Leaving a drinking establishment at a late hour is a possible reason, as is any traffic violation, however minor. But there has to be something that a reasonable person would consider valid for pulling a driver over. Weaving in or slightly over lane markers is NOT a reason to pull you over under the Hardin case.
• Did the police officer have probable cause to administer the BAC level test? Drivers are strongly advised to be quiet when being asked questions at the stop. Even the casual admission to having any alcohol at all is enough to qualify for probable cause. So is having alcohol on one’s breath or slurring one’s words. But again, the police officer must have a credible reason for thinking a person might be legally intoxicated and arrested for a DWI offense.
• Is there video footage of the stop and any roadside tests, like walking in a straight line? The answer better be yes, as officers should have their dashboard camera running during the stop. Our San Antonio DWI lawyer can review the video to see if roadside tests were conducted fairly, especially if these tests are used to establish probable cause for subsequent testing of blood or breath.
• Is the breathalyzer equipment being maintained properly? There are strict rules that police stations must following regarding the breathalyzer equipment. They must be maintained and recalibrated according to specific protocols. Officers need to have completed a training session in how to use them. Any deficiency in following protocol can be used as a basis to challenge the results. Did the officer observe the 15 minute period of time prior to the test.
• What was the driver eating prior to the stop? Did you know that eating bread or sugary foods can cause BAC levels to give off deceptively high readings? Maybe someone is driving home after a wedding where they had cake along with a drink or two. Or they were at Happy Hour and had some appetizers with bread in them over a drink with colleagues. They aren’t intoxicated. But the sugar or bread involved might make it appear so. An experienced attorney will know this.
• Was the driver taking any medication? There are common forms of medicine that can cause BAC levels to rise slightly. Cough syrup is one. Even mouthwash could be the culprit. This is another way where the person who has otherwise drank responsibly, and within the legal limit, can be unfairly charged with a DWI.
• Was the blood test done properly? A blood sample has its own set of protocols that must be observed. These protocols are called chain of custody, and it means the sample must be accounted for every step of the way. From the time the blood is drawn, to its storage, to its testing, to its return to storage. Failure to maintain chain of custody can render the test inadmissible in court. Failure to store the blood properly can cause it to give an inaccurate reading.