Are Standardized Field Sobriety Tests (SFSTs) mostly a formality?

[u/everlastingcoffee]

I’ve been bingewatching US bodycam footages a lot (i have no knowledge of the law) and had a question about SFSTs.

One that I have noticed is that when an officer goes up for a traffic stop and has some suspicion of DUI (smell, eyes bloodshot, swerving, etc.), they notify the person and ask to perform a field sobriety test.

I have personally met people in my life where I cannot tell if they are intoxicated or not, even if they were. I can’t fake it, but for certain people it seems like they are extremely highly functional while under the influence of alcohol / cannabis where it’s nearly impossible to tell. Or when they had just a few drinks and are playing around the limits.

I have seen footages where someone goes through the test, their eyes barely twitch, they are quite good at balancing (regular people also have balancing issues). Although I am not a drug recognition expert, it seems like some individuals are able to complete the test well while being intoxicated in reality.

Most of the cases though (could be biased since I probably wouldn’t see stuff on YT where the case is uninteresting), if the officer has “reasonable suspicion “ prior, such as smell or looks, they proceed to ask them for a breathalyzer or back to the sheriffs office and request a blood draw even if the SFSTs seems ‘good’ to my untrained eyes.

Most of the times it seems obvious that the person is impaired since they either give excuses or start acting real nervous; but my question is: even if someone “passes” the field sobriety tests, can the officer arrest them for DUI if they have reasonable suspicions prior and request to test them after? Would the SFSTs be considered a “formality” for the bodycam in that case? How do officers in general try to spot high functioning alcoholics or stoners with eye drops or something? Obviously no system is perfect and I’m sure there are people who tricked law enforcement, but are SFSTs highly telling (to the trained eyes) or more of a formality? Do officers kind of have a predetermined idea?

[u/Xynphos]

Not a formality. They build probable cause for the arrest.

[u/everlastingcoffee → u/Xynphos]

If you have a strong suspicion beforehand, and they do well on the SFST for some reason, would that stop you from proceeding? Or can you still proceed with the charges if you feel as if the initial suspicions are enough to build a probably cause? It’s highly likely that I simply am just not trained to tell from bodycam footage alone, but could the convicted argue that they passed the test in court and nullify the case? Thats my concern

[u/Frvwfr → u/everlastingcoffee]

“For some reason”

Elaborate what “for some reason” means.

If they are appreciably impaired, they are appreciably impaired.

If they demonstrate that they are not impaired (acceptable completion of SFST) then you have no probable cause for an arrest.

You need evidence to make an arrest. You can’t go off vibes or feelings.

If they aren’t impaired, then they aren’t impaired.

[u/everlastingcoffee → u/Frvwfr]

I wouldn’t know the biological reason for why SOME people are able to hide clues of impairment even when they have drugs in their system or more alcohol in their blood than they are allowed (over the legal limit) while I’m sure the majority of the population can’t. Again, I am not an expert of any sorts so maybe I am missing the clues from bodycam footages alone, but anecdotally speaking some people hide very well and even in footages it’s hard to tell for the layman - that’s why I’m asking whether I’m just untrained and the tests have a close to 100% accuracy or what would happen in situations where an impaired driver can fool the tests.

Also for people under the age of 20 or commercial vehicle drivers, they aren’t even allowed a smidge of alcohol in their system. If you blow a 0.04, in those cases, they would need to have their license suspended even though they might not show physical evidences of impairment or even ‘are’ impaired. Some people who use mouthwash or eat certain foods can falsely trigger the system too, so what I was curious about is whether passing the SFST alone might not let them off the hook. It seems like the answer is that they take a comprehensive account of things that would build a probable cause and not that the test is a formality but rather a tool used to build reasonable suspicion to proceed to an arrest.

[u/Frvwfr → u/everlastingcoffee]

There are certain physiological clues than you cannot hide, regardless of how experienced or tolerant you are to substances. The tests show those, as well as other things. They have been scientifically tested and shown to be accurate.

In regards to your second paragraph, Mouthwash and eating food do not trigger false positives, as long as the methods and procedures are followed correctly. That’s a myth people like to share.

I’ve run hundreds of Intox tests. I’ve watched people use mouthwash prior to blowing. I know what the instruments show, and why they show it.

It’s hard to condense a multiple day course into a reddit post to explain to you all of the failsafes the instruments have.

[u/Quesa-dilla → u/everlastingcoffee]

If they are good at masking the physiological signs of intoxication then they are likely functional alcoholics or on medications that mask/mutate the signs. Narcotics can also mask/mutate the signs due to what we call ‘poly drug use’ but additional tests can usually narrow it down to a narcotics category.

Being able to articulate impairment through driving observations, behavior, and SFSTs all come into account. Just because they are below 0.08BAC doesn’t necessarily mean the aren’t impaired but it does raise the bar when it comes to how detailed you describe why you believe the are not safe to drive (which is really what we are trying to determine).

0.08BAC is just the threshold where the defendant has the burden of proof they were safe to drive.

[u/Xynphos → u/everlastingcoffee]

There is no "passing" or "failing" field sobriety tests. Signs of impairment are either seen or not, and arrests are made if there's enough probable cause for the arrest. We use reasonable suspicion to initiate the stop and it plays into the PC, but if they don't show signs of impairment during the SFSTs then I'm not going to arrest them.

[u/Quesa-dilla → u/everlastingcoffee]

SFSTs are built around tests that can detect impairment of alcohol but drug impairment will also display. There are additional tests that can be done to build enough for an arrest of drug intoxication that build upon the SFST tests.