| A DWI arrest is not a DWI conviction. The most effective DWI defense strategies attack the traffic stop, the field sobriety tests, the breath or blood evidence, and the procedures police are required to follow. If any one of those pieces falls apart, the state’s entire case can fall apart with it. |
Getting pulled over and arrested for driving under the influence feels like the end of the story, but we’re here to tell you it isn’t. Every DWI case is built on a chain of evidence, and every link in that chain can be tested, challenged, and broken. Officers make mistakes. Machines misfire. Tests get administered wrong. Rights get trampled. Our job is to find every weak link in the state’s case and pull until it snaps.
Below are the common DWI defense strategies we use to fight for our clients in Houston and across Texas, the same strategies that have helped us secure 160+ Not Guilty verdicts and thousands of dismissals. Explained the way we’d explain them to you in our office: no promises, just the truth about how these cases actually get won.
Keep reading to find out more about how DWI cases are won, or contact Thiessen Law Firm at (713) 864-9000 or contact us online to start building your defense.
What is the best defense against a DWI?
1. Challenging the legality of the traffic stop
Every DWI case starts the same way: a traffic stop. And every traffic stop has to be legal for anything that happens after it to count.
Officers need reasonable suspicion of a traffic violation or criminal activity before they can pull you over, and they need probable cause before they can arrest you. If an officer can’t point to a specific, articulable reason for that stop, everything collected afterward, including field sobriety tests and breath results, can be thrown out.
We pull the dashcam and bodycam footage on every case and compare it against the officer’s written report. It’s astonishing how often the two don’t match. Maybe the officer claimed you were weaving between lanes, but the video shows a straight line. Maybe the “broken taillight” that justified the stop was never actually broken. These details matter, because without a legal stop, there’s no legal case.
2. Attacking the results of field sobriety tests
Field sobriety tests were never designed to prove you were drunk. They were designed to give an officer a reason to book you. The horizontal gaze nystagmus test, the walk-and-turn, and the one-leg stand are subjective, easy to fail even stone sober, and rarely administered the way the National Highway Traffic Safety Administration actually requires.
These tests don’t account for:
- Uneven pavement, poor lighting, or bad weather conditions at the roadside
- Physical limitations like bad knees, inner ear issues, vertigo, or an old injury
- Age, weight, or footwear that make balance tests unfair from the start
- Nerves, which make almost anyone look shaky in front of a police officer with a flashlight
If the officer skipped instructions, demonstrated the test incorrectly, or graded it based on gut feeling instead of the actual protocol, that test result means nothing in court.
Continue reading: Can you refuse a field sobriety test?
3. Fighting blood test and breath test results
This is where cases are won or lost, and it’s also where we spend most of our time. A breath test or blood test might look like hard science to a jury, but the machines and the people running them are far from perfect.
Breath test results from machines like the Intoxilyzer can be thrown off by:
- Calibration and maintenance failures, which is why we request every machine’s service records
- Operator error during the observation period or the test itself
- “Mouth alcohol” caused by burping, vomiting, or reflux conditions like GERD
- Certain diets, including low-carb or keto eating patterns, which can produce false elevated readings
Blood test evidence has its own problems, including improper storage that causes fermentation, chain of custody gaps, and testing performed by someone who wasn’t properly qualified to draw or analyze the sample. As an ACS-CHAL Forensic Lawyer-Scientist, Mark Thiessen has spent his career learning the chemistry behind these tests so he can pick apart the results in front of a jury, not just argue around them.
He knows Texas blood alcohol content testing methods like the back of his hand. And he’ll tell you that Do Not Blow is some of the worst advice you’ll hear on the internet. In most cases (with very few exceptions), we actually recommend taking the breathalyzer test. Why? If you refuse, it’s likely immediately followed by a blood test, which comes with its own set of issues for your defense.
Wondering whether you had the right to say no in the first place? Continue reading: Can you refuse a breathalyzer?
4. Raising medical conditions that mimic intoxication
Sometimes the “signs of intoxication” an officer swears they saw were never about alcohol at all. Diabetes can cause slurred speech and unsteady balance. Acid reflux can spike a breath test reading without a single drink involved. Anxiety can make your hands shake and your voice crack in a way that looks a lot like nerves and a lot like guilt to an officer who’s already made up their mind.
Medical conditions are one of the most overlooked DWI defense strategies, mostly because clients don’t think to mention them. If you have a diagnosed condition that could explain your behavior, your speech, your balance, or your test results, that information belongs in your defense file from day one. It’s often the difference between a jury seeing a guilty defendant and a jury seeing a person having a medical episode.
5. Exposing procedural errors and rights violations by law enforcement
The DWI process in Texas is governed by strict rules, and law enforcement doesn’t always follow them. When officers cut corners, it can unravel their entire case.
Some of the most common procedural errors we look for include:
- Failing to observe a suspect for the legally required 15 minutes before administering a breath test
- Skipping or delaying Miranda warnings before custodial questioning
- Mishandling or losing physical evidence, including dashcam footage
- Ignoring a suspect’s request to speak with an attorney
Your Fifth Amendment rights protect you from self-incrimination, and if officers questioned you after arrest without reading you your rights, anything you said in that window may never see the inside of a courtroom. These are constitutional protections, and when they’re violated, evidence gets suppressed and cases get dismissed.
6. The rising BAC defense
Alcohol doesn’t hit your bloodstream the second it hits your lips. It takes anywhere from 30 minutes to two hours to fully absorb, which means your blood alcohol level can still be climbing well after you’ve stopped driving.
If you had a drink shortly before getting behind the wheel, there’s a real possibility your BAC was under the legal limit while you were actually driving, even if it tested over the legal limit by the time you were tested at the station an hour later. This timing gap is a legitimate, science-backed defense, and it’s one prosecutors hate having to explain to a jury.
How these DWI defenses work together
Strong DWI defense comes from stacking these strategies together, then finding which one lands hardest with your specific facts.
| Strategy | What it challenges | Potential outcome |
| Traffic stop legality | Officer’s basis for pulling you over | Suppression of all subsequent evidence |
| Field sobriety tests | Administration, scoring, and conditions | Test results excluded or discredited |
| Breath/blood test accuracy | Machine calibration, operator error, lab handling | BAC results suppressed or challenged at trial |
| Medical conditions | Officer’s interpretation of “signs of intoxication” | Reasonable doubt on impairment |
| Procedural/rights violations | Constitutional protections during arrest | Statements or evidence suppressed |
| Rising BAC | Timing of alcohol absorption | Doubt on BAC at time of driving |
Every case is different, and the strategy that saves one client’s license and freedom might not even apply to the next case that walks through our door. That’s why we don’t run a script. We dig into the facts of your arrest, your video, your test results, and your medical history before we ever tell you how we plan to fight.
Common DWI defense strategies FAQ
Is it worth it to fight a DWI case or just accept it?
Almost always, yes. A DWI conviction follows you for years through higher insurance premiums, license suspensions, employment background checks, and in some cases, immigration consequences. Fighting the charge, even when a full dismissal isn’t guaranteed, can lead to reduced charges, suppressed evidence, or an outright win. Accepting a plea before you understand your options is almost never in your best interest.
Can you beat a DWI without a lawyer?
Technically, yes, but it’s an uphill climb no one should attempt alone. DWI cases involve constitutional law, the rules of evidence, and forensic science around breath and blood testing. Prosecutors and their expert witnesses do this every day. Walking in without an experienced DWI attorney in Houston means walking in outgunned.
What are the odds of getting DWI dropped?
It depends entirely on the facts of your arrest and the quality of your legal representation. Cases with a shaky traffic stop, sloppy testing procedures, or clear rights violations get dismissed or reduced far more often than cases built on a clean arrest and solid evidence. An attorney who knows how to spot those weaknesses gives you a real shot.
Facing DWI charges in Texas? Don’t wait to build your defense.
If you’re facing DWI charges anywhere in the Houston area, the clock is already working against you. Evidence gets stronger the longer it sits unchallenged, and deadlines like your Administrative License Revocation hearing (which you have just 15 days to schedule before you lose your license) don’t wait for you to feel ready.
Whether this is your first DWI in Texas or you’re facing repeat charges, the best thing you can do for your future is hire an experienced attorney who knows how to fight a DWI, and has a track record of winning complex cases.
Mark Thiessen and the team at Thiessen Law Firm have spent years dismantling DWI cases that other attorneys wrote off as unwinnable, using the exact strategies laid out above.
Contact Thiessen Law Firm at (713) 864-9000 or contact us online for a free consultation. We’re available 24 hours a day, 7 days a week. Let us take a look at your case before you make your next move.
More Helpful Articles by Thiessen Law Firm:
- How To Get a DWI off Your Record in Texas
- Step-by-Step Guide to the ALR Hearing Process in Texas
- How Long Does a DWI Stay on Your Record?
- How Much Is Bail for DWI in Texas?
- Can a Passenger Get a DWI in Texas?
