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With a 91% success rate on cases announced for trial since 2002, our attorneys are prepared to fight hard in your name.

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Field Sobriety Tests

Other than a chemical test to determine blood or breath alcohol concentration, a police officer in the field may opt to use or also use field sobriety testing to provide probable cause for arrest. These tests can be an accurate way to indicate intoxication under optimal conditions, but frequently such conditions do not exist.

An experienced DWI defense lawyer in the Dallas metroplex can use the variables present in field sobriety tests to fight admitting them as evidence and thereby weaken the prosecution's case against you.

Dallas DWI and Field Sobriety Tests Lawyer

When your DWI case in the Dallas area, including Fort Worth, Richardson, Addison, Garland, Irving, Grapevine, Grand Prairie, Denton, Plano, Frisco, McKinney, Arlington, Mesquite, Carrolton, and Lewisville, involves field sobriety testing, the experienced DWI defense attorneys of The Law Offices of Richard C. McConathy may be able use the lack of reliability in FST results as a defense mechanism for your case.

Richard McConathy and his team will work to get the sobriety test results dismissed, thereby weakening the prosecution's case against you. Your first consultation concerning your Dallas DWI with The Law Offices of Richard C. McConathy is free, so call (972) 233-5700 today and schedule yours.


DWI Field Sobriety Tests and How They're Used

Also known as FSTs, field sobriety tests are standardized performance tests designed to identify whether or not a driver reasonably suspected of DWI could actually be intoxicated. The tests usually involve observations by the law enforcement officer on the alleged intoxicated person's physical and cognitive performance. If the allegedly intoxicated person fails, the police officer has reasonable cause to arrest him or her for DWI. Additionally, video of the tests can be used as evidence at court.

An officer may have reasonable suspicion to conduct field sobriety tests in a number of circumstances. If he or she pulls you over for a standard traffic violation, for instance, the officer will be looking for evidence of impairment on sight including bloodshot eyes or slurred speech.

An officer may also pull you over due to allegedly erratic driving, swerving, or drifting which may indicate intoxication. Additionally, if there is a car accident, looking for signs of intoxication is pretty standard. In any of these scenarios, a law enforcement officer may have reasonable suspicion enough to request you perform an FST in order to obtain reasonable cause to arrest you for DWI.

These FSTs are standardized by the National Highway Traffic Safety Administration (NHTSA), and law enforcement officers in Texas are trained to follow these standards to determine intoxication. However, the variables present in the testing make the judgments made from the tests extremely subjective to the circumstances.

For instance, if the subject of the test has a medical condition or injury, is 65 or older, or more than 50 pounds overweight, the results of the tests may indicate a false positive. It is best not to submit to a FST as there is no Texas law requiring you to do so; however, an experienced Dallas DWI defense lawyer can help you fight the results if you do.


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Examples of Dallas DWI Field Sobriety Tests

The field sobriety tests standardized by the NHTSA test for intoxication based on physical factors alone, mental factors alone, or a combination of mental and physical factors known as a divided-attention test. Failure of the tests gives a Dallas area police officer probably cause to arrest the suspect for DWI. There are many types of FSTs, including the following:

  • Horizontal Gaze Nystagmus (HGN) Test – Nystagmus is an involuntary movement of the eye over which the person has no control, and can be an indicator of intoxication. The test involves the suspect following an object horizontally across their field of vision while the officer looks for lack of smooth pursuit, distinct bouncing or jerking at maximum deviation, or onset of nystagmus prior to the eye reaching 45 degrees.
  • Walk-and-Turn (WAT) Test – The walk-and-turn test is meant to show the suspect's ability to divide his or her attention between the physical element of the walking and the mental element of following instructions and/or counting. The test usually involves taking nine steps heel-to-toe on a straight line, turning on one foot, and then walking nine steps heel-to-toe back to the start. The officer is looking for things like lack of balance, false starts, an incorrect number of steps, and not touching the heel to the toe as signs of impairment.
  • One-Leg Stand (OLS) Test – The One-Leg Stand field sobriety test is another divided-attention test. The suspect is usually required to hold one foot six inches off the ground while counting aloud by the thousands for about 30 seconds. Actions by the suspect such as swaying, using arms to balance, and counting out of order may be indicators of impairment to the officer.

It is important to note that these tests are not 100 percent accurate, and that failure of the test does not necessarily indicate impairment. Perfectly sober individuals have been known to fail field sobriety tests.

An experienced DFW area DWI defense lawyer can work to have the results thrown out if you are shown to have a condition affecting the results, or due to other factors like an improperly trained officer, incorrect test administration, and inaccurate test result grading. Without the FST evidence, the prosecution may not have a case, or their case could be severely weakened.


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The Law Offices of Richard C. McConathy | Dallas-Fort Worth DWI Defense Lawyer

If you are facing a charge for DWI in Dallas County, Denton County, Collin County, Tarrant County, Rockwall County, Johnson County, Wise County, or Ellis County, and your case includes field sobriety test results as evidence, contact the experienced Dallas DWI attorneys of The Law Offices of Richard C. McConathy.

They will work to use the variables in field sobriety testing to the advantage of your defense. To schedule your free initial case consultation with The Law Offices of Richard C. McConathy, call (972) 233-5700 today.


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People ask every day how I'm not in prison, and my answer is to recommend this firm. Thank you again Richard, Brian, Amanda, Christina and Cynthia. God Bless. Nicholas D.
Tarrant County DWI
I can’t say enough great things about the attorneys at this law firm. Within a few months they had my case, which I thought I was going to lose, dismissed and put my life back on track. I would recommend their firm to anyone and everyone who is in need of legal help. Leslie L.
Denton County DWI
As a free man, I would highly recommend this law firm to anyone who is in serious trouble. They will do anything they can to save their clients. In my opinion they are the two best DWI lawyers in the state. Jeffrey F.
Dallas County DWI Intoxication Assault
I would highly recommend this law firm to anyone who has run into some trouble anywhere they might get a DWI. Stephanie C.
Denton County DWI
The Law Offices of Richard C. McConathy PLLC, Attorneys & Lawyers, Dallas, TX