Field Sobriety Testing: Intro

Field sobriety testing for DWI is a crucial element in DWI prosecution and defense. Initially, field sobriety testing serves as the best method by which an investigating officer can ascertain whether the “reasonable cause” referred to in NJSA 39:4-50.4 exists, which in turn would require the suspect to submit to DWI breath testing. It is also the best way the State can establish the probable cause which must be established before a suspect can be arrested and then charged with DWI. Field sobriety testing for DWI can also be used by the Court to ultimately determine whether there are sufficient observations to determine intoxication in the absence of breath test results establishing a per se violation.

Keeping the importance of field sobriety testing for DWI in mind, it is surprising how many police officers, prosecutors, attorneys and Courts lack an understanding of field sobriety testing procedures. Many times, Courts make decisions of great importance in deciding issues of probable cause and ultimate guilt based upon misunderstandings with regard to these tests. The purpose of this article is to identify problems which exist with regard to field sobriety testing for DWI and then to rectify these problems by reviewing proper field sobriety test procedures and evaluation techniques.

The greatest problem with current field sobriety testing for DWI involves a failure to rely upon what are known as Standardized Field Sobriety Tests. The accompanying problem involves an unquestioning reliance upon what I refer to as “anecdotal” field sobriety tests. Standardized Field Sobriety Tests were developed as the result of research conducted in the mid 1970’s for the National Highway Traffic Safety Administration.

This agency is part of the United States Department of Transportation. Its purpose is to advance motor vehicle safety throughout the United States, with regard to DWI enforcement and other vehicle safety issues.

The purpose of this research was to develop standardized tests which would provide a reliable method of determining intoxication from field sobriety tests. The means through which the reliability of these tests was established, was through studies repeated over a number of years by the NHTSA. As a result of these repeated studies, levels of confidence or “reliability” has been established which helps in understanding and using SFST test results.

All too often, Courts are willing to accept anecdotal field sobriety tests simply because they “seem” to be reliable. Courts regularly and without question, accept sway tests (frequently with the suspect’s eyes closed), finger to nose tests (again with eyes closed), alphabet tests, finger counting tests and other similar tests, as reliable evidence of intoxication, simply because they “seem” to indicate intoxication. Frequently, Courts will rely on observations which result from these tests without having any testimony of Standardized Field Sobriety tests before them.

Anecdotal tests are unreliable because they are neither standardized nor tested to determine reliability. Since no procedure exists to administer these tests, there is no way to determine if tests are given the same way each time. Obviously, if the scientific method serves as the basis for establishing the reliability of a test, the test must be standardized. This is the case with Standardized Field Sobriety Tests which require adherence to established procedures in explaining, demonstrating and then administering tests.

In the case of Standardized Field Sobriety Testing, officers are trained to look for established “scoring factors” which must be evaluated in determining whether or not intoxication exists. A finding of intoxication can only arise once sufficient scoring factors are identified. Upon the identification of only a single scoring factor, an evaluation would be required of a high degree of probability of non-intoxication. When additional scoring factors are identified, probabilities of intoxication are assigned to evaluate test results.

With this in mind, the following information is provided with regard to the three Standardized Field Tests, which are the Walk And Turn Test, the One Leg Stand test and the Horizontal Gaze Nystagmus tests. It is hoped that this information will raise the awareness of the bar and bench in particular, as to the existence of these tests, the lack of scientific basis for anecdotal tests and the need to limit evidence at the time of trial to scientifically reliable field sobriety testing.