In Texas, if a police officer has reasonable suspicion for a DWI offense, they can ask you to do a field sobriety test. If you fail the field sobriety test, it will give them probable cause to arrest you for DWI.

Unfortunately, field sobriety tests are not always an accurate way of determining whether someone is impaired due to intoxication. In this article, we’ll cover what to expect from field sobriety tests in Texas.

What Is a Texas Field Sobriety Test?

Field sobriety tests in Texas, also known as Standardized Field Sobriety Testing (SFST), consist of a series of three performance tests that are used by police officers to determine if a driver is impaired. They are designed to test a person’s balance, coordination, ability to accurately listen and act on instructions, and their ability to divide their attention to multiple tasks or instructions during the test.

Types of Texas Sobriety Tests

There are three types of field sobriety tests in Texas, including the Horizontal Gaze Nystagmus (HGN) test, the Walk-and-Turn (WAT) test, and the One-Leg Stand (OLS) test, each designed to test whether a person has normal use of their mental and physical faculties.

Horizontal Gaze Nystagmus (HGN) Test

Designed to observe and assess your eye movements, nystagmus tests consist of the trained officer slowly moving an object such as a pen or small flashlight and requesting that you follow with your gaze only.

When conducted correctly, the following clues could indicate intoxication:

• Lack of smooth pursuit in one or both eyes
• Distinct and sustained nystagmus (jerky eye movements, side-to-side, up and down, or in circles) in one or both eyes

Before the test begins, the officer will probably also look for other signs of impairment, including red or bloodshot eyes, and dilated pupils.

Walk-and-Turn (WAT) Test

The Walk-and-Turn test is a divided attention test. Starting from a heel-to-toe position, the officer will ask you to take 9 steps, one step in front of the other, heel to toe, in a straight line. After the ninth step, you would need to turn, and take 9 steps to get back to where you were. The officer will ask you to keep your arms at your side, and to not start walking until they say so.

The officer will look out for the following clues that may point to intoxication:

• Poor balance during the instruction phase
• Beginning the test before being instructed to do so
• Not touching your heel to your toe
• Stepping off the line
• Pausing during the walk
• Lifting your arms (more than 6 inches) for balance
• Improper turn
• Incorrect number of steps in either direction

One-Leg Stand Test

This standardized test is designed to test your balance. You’ll be asked to lift one foot around 6 inches off the ground and count from one thousand up (1001, 1002, 1003, etc) until you are instructed to put your foot back down, usually after around 30 seconds.

The officer will watch out for the following signs of intoxication:

• Swaying
• Using arms for balance (by lifting them more than 6 inches)
• Hopping
• Putting your foot back down before instructed

Are Field Sobriety Tests Mandatory in Texas?

You have the right to refuse to participate in field sobriety tests in Texas—they are not mandatory.

Although refusing to participate in the test does not result in a penalty, you should know that it may result in other consequences, and likely your arrest. After refusing to do a field sobriety test, you will have your license revoked and instead be given a temporary driving permit. You will probably be asked to do a breathalyzer or blood test, too.

Furthermore, your refusal may be used against you as evidence by the prosecution in a DWI case. That said, if an officer is asking you to conduct field sobriety tests, it is likely that they’ve already determined you are impaired and are just trying to gather evidence to use against you. 

We always recommend that our clients refuse to comply with any and all field sobriety tests, including blowing into a breathalyser or voluntarily giving a blood sample. It is your constitutional right to refuse to comply with these tests, and a good criminal defense lawyer will be able to rebut any of the State’s attempts to use your refusal as evidence of guilt against you. The fact is that the fewer tests you agree to take, the less evidence the State will have to try and use against you, which makes your lawyer’s job easier, and the State’s job harder. 

What is the “No Refusal” Weekend in Texas?

“No refusal” weekends are set weekend dates, usually around holiday weekends, where police officers have a temporary warrant from a judge allowing them to take blood samples from DWI suspects—under force, if necessary—to provide evidence of intoxication.

Under normal circumstances, if you refuse field sobriety and chemical testing, the police officer will have to obtain a blood search warrant from the district judge, and it can take a while for it to go through. During “no refusal” weekends, the process runs much more smoothly for officers since they have one less roadblock.

Common “no refusal” weekend dates include, but are not limited to:

• St. Patrick’s Day
• Memorial Day Weekend
• Independence Day
• Halloween
• Christmas
• New Year’s Eve

Regardless of whether a “No Refusal” period is in effect, we always recommend that our clients refuse to comply with all field sobriety tests. 

Are Field Sobriety Tests Effective?

Although the State would like the public to believe that field sobriety tests can give a highly accurate indication of whether someone is intoxicated, in reality many variables can distort the results, because these tests are rarely taken under optimal circumstances. The results of field sobriety tests are mostly subjective.

Some of the factors that can give false positives include a person being overweight, a foot, ankle, or leg injury, uneven terrain, slippery conditions, wearing heels, or a particularly loud or windy environment.

It’s also important to consider any health issues that the suspect may have—some underlying health conditions can result in poor balance. Additionally, balance tends to deteriorate with age, declining from as early as 50 years.

Aside from all of the above factors, field sobriety tests can only be measured accurately if the test is conducted correctly by a properly trained officer. An experienced DWI lawyer will closely examine all the evidence and come up with a strategy to fight against field sobriety results.