DUI Field Sobriety Tests: Show me the randomized double blind placebo control studies with significant N-values published in reputable journals showing that DUI field tests are reliable…hands, hands, hands…there aren’t any.
The National Highway Traffic Safety Administration (NHTSA) developed standardized field sobriety testing (SFST) for DUIs in the 1970s. The goal of the SFST was to create a set of standardized tests that could be used by law enforcement officers in the field to assess whether a driver should be arrested for DUI.
The SFST consists of three tests: the Horizontal Gaze Nystagmus (HGN) test, the Walk and Turn (WAT) test, and the One Leg Stand (OLS) test. The HGN test looks for nystagmus, which is involuntary eye movement that can be a sign of the presence of alcohol. The WAT and OLS are divided attention tests which measure the ability to perform a physical task and the ability to follow instructions just like driving where you have to drive and read road signs, traffic markings and signals.The WAT test assesses a driver’s ability to walk, balance, and follow instructions (without being told that following instructions was being measured) and the OLS test assesses a driver’s ability to stand on one leg and follow instructions.
The SFST was developed through a series of research studies conducted by NHTSA. There was only laboratory study with only 15 participants and two field studies conducted late at night when there are more drunk drivers out. No field studies were performed randomly on sober drivers. These studies looked at the relationship between the results of the SFST and whether a correction arrest decision was being made based on a probability of a subsequent blood alcohol concentration (BAC).
Types of research studies:
- Case studies are observational studies that focus on a single individual or small group of individuals. They are often used to generate hypotheses for further research. For example, a case study might be used to investigate the effects of a particular DUI standard field sobriety test on a driver’s ability to drive.
- Correlation studies look for a relationship between two variables. For example, a correlation study might look for a relationship between alcohol consumption and driving performance. However, correlation does not equal causation. Just because two things are correlated does not mean that one causes the other.
- Longitudinal studies follow a group of individuals over time. This type of study can be used to track changes in driving behavior over time, or to see how the accuracy of DUI standard field sobriety tests changes over time.
- Experimental studies are the most rigorous type of research study. They involve randomly assigning participants to different groups and then exposing the groups to different treatments. This type of study can be used to determine the effectiveness of different DUI standard field sobriety tests, alcohol blood tests, and alcohol breath tests.
- Clinical trials are a type of experimental study that is conducted in a medical setting. They are often used to test the safety and efficacy of new drugs or medical devices. Clinical trials can also be used to evaluate the effectiveness of different DUI standard field sobriety tests, alcohol blood tests, and alcohol breath tests.
- Randomized double-blind placebo controlled trials (RDBPC) are the gold standard for clinical research. In an RDBPC, participants are randomly assigned to either a treatment group or a control group. The treatment group receives the intervention being studied, while the control group receives a placebo. The placebo is a fake treatment that looks and tastes like the real treatment, but it does not contain any active ingredients. This helps to ensure that the results of the study are not due to the placebo effect. RDBPC studies are considered the “gold standard” of research studies
The Florida laboratory study, Colorado Field Study and San Diego Field study conducted by NHTSA are all correlation studies. In these studies, the researchers looked for a relationship between the results of DUI standard field sobriety tests and the participants’ blood alcohol concentration (BAC). The researchers did not randomly assign participants to different groups or expose them to different treatments.
The results of these studies showed that there is a mere correlation between the results of DUI standard field sobriety tests and correct arrest decisions but do not show causation or impairment. However, the correlation is not perfect. This means that there are false positives and false negatives. False positives occur when a driver who is not impaired by alcohol fails the DUI standard field sobriety test. False negatives occur when a driver who is impaired by alcohol passes the DUI standard field sobriety test.
The high number of false positives in the Florida laboratory study, Colorado Field Study and San Diego Field study suggests that the relationship between the results of DUI standard field sobriety tests and BAC is not perfect. This means that these tests should not be used as the significant basis for determining whether a driver is impaired by alcohol. Age, weight, physical ability and physical condition all play a role in the ability to stand on one leg and walk a line like a balance beam. Other evidence, such as appearance and demeanor, and chemical testing, should be used in conjunction with DUI standard field sobriety tests to make a more accurate determination of whether a driver is impaired by alcohol.
The results of these studies also suggest that the accuracy of DUI standard field sobriety tests can be affected by a number of factors, such as the stimulus speed and distance used in the tests. This means that the results of these tests should be interpreted with caution.
Discussion
The false positive rates of the Florida laboratory study, Colorado Field Study and San Diego Field study are all high. This means that a significant number of drivers who are not impaired by alcohol will fail these tests. This can lead to innocent drivers being arrested and charged with DUI.
The fact that field sobriety tests do not measure impairment but simply suggest to an officer whether or not a correct arrest decision is being made, i.e., probable cause and are not useful to determine if someone is guilty beyond a reasonable doubt of being less safe due to alcohol, means that they should not be used as a significant factor for determining whether a driver is impaired by alcohol. Other evidence, such as actual manner of driving, the person’s appearance and demeanor (do they look drunk), an alcohol breath test or an alcohol blood test, should be used in conjunction with field sobriety tests to make a more accurate determination of whether a driver is impaired by alcohol beyond a reasonable doubt.