Standardized Field Sobriety Test and Age: 40 is the new 65

Standardized Field Sobriety Test and Age: Why At Age 40 You Are Over the Hill

The Standardized Field Sobriety Tests have been used since the 1980’s to aid officers in the field in their decision-making to arrest motorists. But are they useful for all ages?

When I turned 35, I started to get direct mailing from the AARP wanting me to join and be a member. I really didn’t get it. The AARP is for retired folk. I’m still supposed to be in my prime for crying out loud.

Standardized Field Sobriety Tests and Age

Little did I know that the AARP is right. It seems as if according to the P.R. Dixon et al. in their 2009 published peer reviewed paper “Evaluation of a roadside impairment test device using alcoholAccident Analysis and Prevention 41 (2009) 412–418, once we turn 40, the science shows that we start to rapidly deteriorate in our non-ethanol induced performance on the Standardized Field Sobriety Tests.

As we can see in the below figure 4, the magic age where we start to disproportionately record false positives in the Standardized Field Sobriety Tests in terms of the decision clues is 40+ years old.


That’s quite a difference from the Standardized Field Sobriety Test student manual. In the Standardized Field Sobriety Test student manual we find the following in the text, for the Walk and Turn test: “the original research indicated that individuals over 65 years of age, back, leg or inner ear problems had difficulty performing the test.”
Remember the Standardized Field Sobriety Tests are not designed to determine or record impairment, just Probable Cause for arrest as part of the properly conducted 3 phase (Vehicle in Motion, Personal Contact, and Pre-Arrest Screening) DWI Detection as originated by the Southern California Research Institute and through the Department of Commerce and the National Highway Traffic Safety Administration.
According to SCRI/NHTSA:ALL 4 conditions must be present, if not then not a valid test1. Suitable environment
2. Suitable motorist (health, nervousness) who can preform the test
3. Instructed properly
4. Interpreted (graded) properlyAlso pharmacodynamically, the Standardized Field Sobriety Tests make some fatal assumptions:Everyone is physically capable of doing these tests
Everyone is emotionally capable of doing these tests
Everyone can do these tests in that roadside environmentAny deviation has to be due to ethanol and ethanol alone.

Infrequently do all of the conditions precedent present and all of the assumptions apply. If any of the conditions precedent and and if any of the assumptions are not proven to apply to the motorist accused, then there is a non-validated result.

Leave a Reply

Your email address will not be published. Required fields are marked *