DC Field Sobriety Tests and Traffic Stops

In Washington, DC, you may be arrested for a DUI even if the officer only had reasonable suspicion to make a traffic stop for some other offense. Traffic violations that constitute reasonable suspicion, or just cause for a stop, can include making a rolling stop, having a broken tail light, or even having illegally tinted windows.

Upon making this “justified stop,” the officer then must identify clues that the driver might be under the influence of alcohol or drugs. If you have been the subject of a DC DUI traffic stop, you should immediately retain the services of a dedicated DUI defense attorney.

The visual clues that an officer might use in DC DUI traffic stops can include one or more of the following:

Police officers also use their sense of smell during a traffic stop to gauge whether a driver has been drinking. They might be able to detect a lingering odor of alcohol on the suspect or in the vehicle, cover-up odors, or the smell of excessive perfume or mints on the suspect.

Standardized Field Sobriety Tests

If an officer suspects that a driver may be impaired by alcohol or drugs, certain tests are administered to confirm the suspicion. First, they will ask for the driver’s license, vehicle registration, and proof of insurance. This simple sequence of tasks identifies the suspect’s ability to focus on the request and perform these simple tasks.

Often, as the suspect is producing the requested documents, the officer engages the suspect in off-topic conversation, which can distract the driver as the documentation is being located and produced. Proof of the driver’s impairment may become obvious if they struggle to focus on both the conversation and fulfilling the officer’s request. This gives the officer evidence of psychological impairment due to excessive alcohol consumption and points of reference for the following three Standardized Field Sobriety Tests (SFSTs) that are then administered.

• Horizontal Gaze Nystagmus Test (HGN)
• Walk-and-Turn Test (WAT)
• One-Leg Stand Test (OLS)

According to the National Highway Traffic Safety Administration (NHTSA), these are the most accurate ways to determine driver impairment. By the time the officer requests that a driver perform the field sobriety tests, they already suspect that the driver is under the influence of some form of intoxicant, and that can often bias them to misread clues that are produced by any or all of the field sobriety tests. This can lead to mistakes that produce a false arrest, especially if the driver might have a pre-existing physical limitation or affliction that may be mistaken for intoxication.

Horizontal Gaze Nystagmus (HGN)

The officer begins this test by passing a hand-held object such as a pen or flashlight in front of the driver’s face while telling the suspect to follow it with their eyes. Normally, a person’s eyes track a stimulus smoothly and equally, but when someone is under the influence of alcohol or drugs, the eyes lag behind the object and then jump or jerk to correct themselves. This is an involuntary reaction which is called “nystagmus.” If the nystagmus is extreme, the officer assumes that the suspect’s intoxication level is higher.

The officer will make several passes to observe “distinct and sustained” nystagmus. Then he or she might do several “vertical” nystagmus tests, which is the same process, but follows an up and down pattern. This will likely reinforce the observations of the HGN.

Certain prescription drugs that treat epilepsy or other seizures can cause nystagmic reactions during an HGN test. Those who are severely nearsighted, have astigmatism or inner ear problems, or who have suffered past damage or trauma to the brain might also suffer from nystagmus.

Walk-and-Turn Test (WAT)

The officer instructs the driver to place their hands firmly at their sides and walk heel-to-toe as many as nine times before then turning and walking back towards the officer in the same fashion. According to NHTSA, there are eight clues that indicate impairment as the driver performs the test:

• Losing balance while the officer explains how the test is performed;
• Beginning the test before being told;
• Abruptly stopping after starting the test;
• Stepping out of line;
• Breaking the heel-to-toe walk by more than half an inch;
• Raising arms more than six inches to regain balance;
• Turning improperly; and
• Taking an incorrect number of instructed steps.

In addition to footwear problems, such as drivers wearing high heels, other conditions such as back, leg, or inner-ear problems, fatigue, and old age may also pose challenges for someone performing a WAT test. This test also incorrectly assumes that all people, whether sober or intoxicated, have the same balance and physical abilities.

One-Leg Stand (OLS)

This is a “divided attention” test that requires the driver to perform a physical task after receiving instructions. The officer tells the driver to stand with both arms firmly at their sides, raise one foot approximately six inches off the ground, and count aloud until told to lower the foot. The officer times the subject for 30 seconds. The four clues of impairment the officer is looking for include two or more of the following:

• Raising arms to balance;
• Swaying while balancing;
• Hopping to maintain balance; and/or
• Putting the foot down before being told to by the officer.

Research indicates that failing the test equates to a 65 percent chance of having a BAC over .10 percent. However, as with the WAT test, the same “false positives” could be present in the OLS test and serve as a basis for defense, especially if subsequent BAC ratings might appear shaky. Results for an OLS are also not universally reliable for drivers who are 50+ pounds overweight, senior citizens, or bothered by back or leg issues. This test also presupposes a standard level of balance and physical condition for everyone, which is a flawed presumption.

Problems with Field Sobriety Tests

Law enforcement and courts rely on the standardized field sobriety test results in determining if a person was impaired while driving, choosing to take a DUI suspect into custody, and administering a BAC test. When properly administered, field sobriety tests have some validity, but they can also discriminate against innocent drivers who are nervous, physically disabled, fatigued, or senior citizens.

The officer giving the test can be prejudiced when the tests are administered, which means it is likely that the driver could be misidentified as under the influence when that is not necessarily the case. Considering that the officer is the sole judge of how the driver performs the tests, and the driver voluntarily submits to them, drivers should carefully consider whether or not to perform the SFSTs, especially if any mitigating circumstances might exist to give the police officer a false impression.

Defending DUI Cases

An experienced DC DUI attorney can argue issues of the officer’s “probable cause” to stop and field test you, and even the results, especially if you informed the officer of any physical limitations that might mistakenly influence the officer’s judgment.