The two kinds of DUI tests are field sobriety tests and chemical tests. FSTs measure a defendant’s physical dexterity and mental acuity. Normally, these tests don’t prove intoxication, but they establish probable cause for a chemical test. This chemical test is nearly always a Breathalyzer breath test and, in a few cases, a blood test. If the defendant fails FSTs and fails a chemical test, the state’s trial winning percentage is over 80 percent.
That high figure is a bit deceptive. The combination of failed FSTs and failed chemical tests intimidates many defense lawyers. They surmise the case is hopeless and look for an easy way out or a quick settlement. But a good Marietta criminal defense lawyer doesn’t give up just because things look bad. FSTs and chemical tests have serious flaws, as outlined below. If a lawyer effectively leverages these flaws during pretrial negotiations, a successful resolution is likely, not just possible.
DUI Investigations
Before we explain DUI tests, we should touch on reasonable suspicion DUI investigations. Before officers ask suspects to step out of the car, they must establish reasonable suspicion (an evidence-based hunch) of intoxication. This evidence generally includes:
- Erratic driving, usually driving very slow or inability to control the vehicle,
- Physical symptoms, such as bloodshot eyes and an odor of alcohol, and
- Statements, such as “I only had one beer.”
Usually, this evidence alone is sufficient. If necessary, officers can supplement this evidence with a hunch. The hunch may be based on the time of day (or rather time of night in most cases) and the location’s physical proximity to a place that serves alcohol.
Field Sobriety Tests
After extensive study, the National Highway Traffic Safety Administration approved a three-test FST battery for use in Georgia. These three tests, along with some reliability issues that plague these tests, include:
- Horizontal Gaze Nystagmus: The “follow my finger” DUI eye test checks for nystagmus, which is an involuntary pupil movement at certain viewing angles. Controlled-condition indoor HGN tests are very reliable. Uncontrolled-condition outdoor HGN tests, especially nighttime tests, are much less reliable. Furthermore, nystagmus isn’t proof of intoxication. Many other things cause this condition which is also known as lazy eye.
- One-Leg Stand: We mentioned the intimidation factor above, and the one-leg stand test is a good example. Arresting officers invariably testify that suspects “failed” the OLS, often based on technicalities like lifting the wrong leg, a barely perceptible sway, or dropping the leg a millisecond too early. That’s like saying Mike failed the history test if he got a 90.
- Walk-and-Turn: Like the OLS, the WAT (walking a straight line) is a divided attention test. It measures physical dexterity and mental acuity. The suspect must walk a straight line heel to toe, which is almost impossible unless s/he’s wearing athletic shoes, and follow directions, like take a precise number of steps.
However, we’re getting a little ahead of ourselves. Frequently, officers administer unapproved FSTs, such as Romberg’s balance test (the finger-to-nose test).
Unapproved tests have no NHTSA backing and are therefore usually unreliable. But they sound good to jurors and wear suspects out, mentally and physically, so they do worse on the tests that really count. If a suspect does poorly on the three-test battery, a Marietta criminal defense lawyer can ask jurors to take that factor into account.
Sometimes, a Marietta criminal defense lawyer allows the state to introduce these test results as evidence, giving the state enough rope to hang itself. Romberg’s balance test is an excellent example.
This test deprives people of three things needed to maintain balance. Many officers don’t know what these three things are. Many other officers can’t explain advanced concepts like proprioception (the awareness of the body in space) to jurors. So, once again, the officer looks bad.
We’ve repeatedly stressed reliability in this section. Reliability is not synonymous with accuracy. A broken clock is accurate twice a day, but a broken clock is unreliable.
Chemical Tests
Georgia has a per se DUI law. Defendants with an AL (alcohol level) of .08 or higher are intoxicated as a matter of law. A different AL applies in some cases. For example, the commercial driver AL is .04. The AL could be breath alcohol or blood alcohol, a minor feature that makes chemical test reliability much easier to establish.
A Marietta criminal defense lawyer cannot use breath/blood conversion issues to undermine Breathalyzer tests. These issues include a failure to carefully watch the suspect to ensure that s/he doesn’t burp or belch before the test, as these acts skew the breath test results.
However, improper device calibration, the most effective weapon, is still available. Police Breathalyzer techs crow about this gadget’s advanced features. Commercial coffee makers make better cups than Sanka and boiled water, but commercial coffee makers are much harder to maintain.
Usually, the state has the burden of proof to show the Breathalyzer used in that case had an appropriate maintenance record and a 100 percent accuracy rate.
On a related note, the suspect’s body temperature affects Breathalyzer results. Officers cannot calibrate these gadgets on the fly, so a Breathalyzer never accounts for this variable.
Blood tests are almost 100 percent reliable and accurate. However, these tests often have non-scientific reliability issues.
Chain of custody is one example. If the state cannot account for every stop in the result’s journey from the defendant’s body to a lab to an evidence room to a courtroom, the sample’s integrity is questionable. Additionally, many Marietta criminal defense lawyers order re-tests. Degreed chemists and other highly qualified professionals often obtain different results, especially in .08. .09, and other borderline AL cases.
Understanding DUI tests explained is often the key to a successful outcome. For a free consultation with an experienced Marietta criminal defense lawyer, contact The Phillips Law Firm, LLC. The sooner you reach out to us, the sooner we start working for you.
