D.U.I. Investigations – Safety Considerations

[Ed. note – This is the final part of a six part DUI Training series. Prior articles covered One Leg StandHorizontal Gaze Nystagmus, Walk and TurnVehicle in Motion and Personal Contact.]

In my previous articles on D.U.I. investigations I tried to refresh and condense the basics of locating, contacting, and testing suspected impaired drivers. In no way should an officer read over my articles and feel like they’re trained up on NHTSA approved D.U.I. investigations. To get proper police training you need to attend a 24 to 40- hour course that specifically teaches the NHTSA approved principles and includes practical exercises.  Without the proper training, expect a specialist DUI attorney to rip you on the stand.

My hope is that the articles will encourage police officers who do not have that training to obtain it, and to renew the interest of cops who have been trained to once again go on the hunt for those careless drivers that wreak havoc on our roadways.

This article is meant to look outside of the standard training and refresher information and consider officer safety and other important considerations when conducting D.U.I. investigations.


It all starts with our first observations of a vehicle in motion (or not – think crash or the driver passed out behind the wheel at the green light) that begins our first suspicions that we may be dealing with an intoxicated driver. The decision to stop should be based upon observed violations, probable cause, or at a minimum reasonable suspicion that criminal activity is afoot. As I’ve said before, if you’re proficient with the administration of the SFST’s the defense attorney will attack the stop itself. If successful in attacking the reason for the stop, then anything after that will be fruit of the poisonous tree and will not be admitted.


Image courtesy of Jeffrey Smith

If you haven’t noticed in recent years there is a very common question that is coming out of the State and Federal courts around the country. That question is – were the officers reasonable in their actions?

By now you should be very familiar with the U.S. Supreme Court case Graham v. Connor (1989) and its implications on how law enforcement is viewed by the courts and the public. This case was a very important victory for law enforcement as it set the national standard that courts must view an officer’s actions based upon the objective reasonable test when viewed in the eyes of a reasonable officer faced with similar circumstances.

In essence the Supreme Court said that subjective (Monday-morning quarterbacking) by courts was not allowed. The decision of reasonableness is based on the totality of the circumstances, and it is viewed from the officer’s perspective at the time of action.

However, there is another “reasonable” test that has been around much longer than the Graham ruling. That test is called common sense. When officers take an objective and practical approach to everything they do, they can easily defend their actions using the common sense test. Sometimes common sense will cause officers to step outside of normal procedures because to stay within procedures would be considered unreasonable. A great example is handcuffing an elderly or injured person with their hands in front of their body instead of behind them.


In regards to DUI investigations the rule of common sense will come into play on a routine basis and should weigh heavily in an officer’s mind when making decisions. Throughout my training in DUI investigations a saying was repeated to help officers determine if conducting the tests were reasonable – “would I want my mother, sister, (etc.) tested under these circumstances”. Here are a few of the most common considerations and suggestions when conducting DUI investigations:

WEATHER – If the weather makes conducting the SFST’s roadside impractical or downright dangerous, than don’t do them roadside. An example is when its raining heavily, snowing, high wind gusts, extremely cold, etc. I have conducted SFST’s in a light rain, and can articulate why – if it’s lightly raining we all are going to get wet moving to and from our cars so it is not unreasonable to get a little wet doing the tests. I will document the conditions, including the fact that the surface of the test was wet but not overflowing in water.

NHTSA does recommend a hard, “dry” surface, so the amount of rain is a pivotal decision maker. In a moderate or heavy rain, performing the tests lacks common sense and an alternative location must be found. Same goes for other weather extremes. Where I’m from, winter temperatures can drop to below zero with wind chills in the negative temperatures. I don’t even want to be in that weather for long, so it is entirely unreasonable for me to expect my subject to. Richard and Randall live in sunny Florida, where hurricanes occasionally visit. I would not recommend administrating SFST’s in such conditions.

ROAD HAZARDS – I have the luxury of working in a medium size suburb of a large metropolitan area. As such, most of our roads provide ample and safe locations for testing DUI subjects. Many in law enforcement have to deal with rural roadways in less than ideal locations. As a general rule do not conduct SFST tests on hills (NHTSA says relatively flat surface), curves in roads, on bridges (creates a whole new meaning to “falling down drunk”), on dirt or gravel (NHTSA says relatively hard surface), or any other roadway condition that presents an obvious hazard to you and the subject.

Try to conduct the tests in a well lit area, but obviously in rural areas the lights from your patrol car and flashlight may be your only source of light. Another consideration about roadways is that most of them are not very level. There is an engineering feature of roads that causes them to be several inches higher in the center of the roadway than on the sides. This allows for greater water removal through the use of gravity. For some roads the rise is almost imperceivable, but others it is blatantly obvious. Consider using an adjacent sidewalk or parking lot.

TESTING LOCATION – There is a lot of debate about where we conduct the SFST’s when roadside. I always wanted to get the tests on video, which required the subject and I to be in front of my patrol vehicle, and usually behind their vehicle. For obvious reasons this becomes somewhat hazardous on highways due to the threat of rear-end collision.

To counter that threat I would always back my car 2-3 car lengths back, and have my backing officer do the same behind my patrol car. By doing so I provided two vehicles, and about 5-6 car lengths of distance between the testing site and a potential rear-end collision. On lower speed roadways the distances should not need to be so drastic. Highways are dangerous and officers need to consider what is reasonable when conducting SFST’s there.

I understand that some officers will not have a backing officer so they may need to go in front of the suspect’s vehicle to conduct tests. I would still back the patrol car up a bit to provide additional buffer. Losing video of the tests is better than losing a life. Be reasonable.

REMOVING SUSPECT FROM THE SCENE – This will probably be the most contentious of the safety considerations, but the topic must be discussed. I have heard many officers say that if any of the above safety issues arises that they will simply take the suspect to the station, or to a different location to conduct the tests. This is a very sticky legal consideration and I highly recommend officers consult their local prosecutors before making a final decision on this topic.

Constitutional law says that anytime a citizen reasonably feels that they are no longer free to leave because of an officer’s actions, than they are under arrest. The U.S. Supreme Court has said that brief detentions for car stops or investigations are legal under the 4th Amendment, so long as they do not exceed the necessary time to conduct the investigation for which the person was stopped.

It is hard to articulate that taking someone to the station or even down the road would not lead a reasonable person to believe that their freedom to leave has been taken away. As such, if the person is under arrest, many jurisdictions say that evidence obtained after the arrest cannot be used as justification for the arrest. There must be probable cause for the arrest to be valid.

This is completely different than making an arrest, reading Miranda, and obtaining a confession. It is also different than making an arrest and later obtaining fingerprints, DNA, or hair samples. The justification for arrest is probable cause, and in the previous examples there should have been probable cause to arrest prior to obtaining the additional evidence.

The difference is the SFST’s are directly linked to establishing probable cause for an arrest. Therefore, judges will most likely not allow SFST evidence that was obtained after a subject was “arrested” to be used as evidence of their intoxication. In those situations your documentation of the other stages of DUI investigation had better be sufficient to make your case.

I have consulted my local prosecutor and found a solution to this dilemma. If I have reasonable belief that the suspect is DUI based upon vehicle in motion, and personal contact (perhaps even pre-exit tests or an initial HGN in the car), and there are safety considerations that prohibit SFST’s in the field, then I will arrest the driver for the original traffic violation.

Once at the station I begin a “new” investigation into the driver’s potential DUI condition and I am allowed to conduct SFST’s and include their results in making a determination to arrest the driver for the “new” offense of DUI. This solution is ONLY used as a last resort when conditions do not allow SFST’s to be conducted in the field.

Because the driver was not originally arrested for DUI, then the “new” investigation allows me to collect evidence in the subsequent charging of DUI. This would be like arresting a guy for stealing, and once at the station asking him questions about a burglary. Since the burglary is separate, if incriminating evidence is obtained, than the suspect could be charged based on that information. The officer is not, however, asking questions about the stealing after the arrest has already been made, and then using that information as the basis for arrest. Again, consult your prosecutors for guidance.

[Ed. note:  Many jurisdictions do not allow the arrest of a driver for a traffic violation, while others do.  Definitely consult your state’s laws, department policies and local prosecutor’s office.]

Another possible solution is to ask the driver if they would be willing to go to a different location for testing. This opens a pandora’s box as many drunks will say “no” and you’re right back in your original dilemma. However, if the driver says “yes”, than you have obtained consent to take the driver away from the stop scene, and therefore there is no arrest. SFST’s that follow will be legally allowed in court because of the consensual situation you’ve created. Consult your prosecutor on this one too, as the wording of this consent may need to be refined to ensure legal acceptance to the court.

CONSIDERATIONS OF THE SUSPECT – In being reasonable we have to realize that our suspect may not be able to perform the tests due to physical limitations. When this occurs do not be the officer that is on video forcing the grandma holding a cane to do the One-Leg-Stand. Use alternative tests, and base your decision on the totality of the circumstances (vehicle in motion, personal contact, and SFST’s) not just one test.

The NHTSA approved tests were validated as tests that scientifically could show impairment in persons under the influence of alcohol or drugs. However, the test subjects did not include elderly or extremely overweight persons. Because of this the tests are not validated for such groups of people and officers should use common sense when conducting tests on such people. The tests are good, and HGN is not influenced by age or weight. It simply means that nobody in those groups of people were tested so they cannot say that the tests are validated for those groups.

Using the common sense approach avoid testing someone who has obvious physical impairments. Use HGN and perhaps some of the other tests I’ve mentioned and then make a sound judgement based upon all of your observations. However, just because they have a handicap does not necessarily exclude them from being tested.

One Halloween night I stopped a guy dressed like a pirate – peg leg and all. Come to find out, underneath the fake wood the guy had a fake leg. He’d had the fake leg for 10 years or more. Using common sense and reasonableness I decided that a guy who had been walking on a fake leg for 10 years should be able to perform the tests. In fact, I reasoned that because he had to compensate for a fake leg, this guy should actually be more balanced than an average person because he had to overcome his handicap to get around. Obviously I had him stand on his good leg for the One-Leg-Stand test. My reasoning was accepted in court, the tests were admitted, and he was convicted.

In the final thought it is all about what makes sense, and what is reasonable. If you can document your thought process and leave a clear mark about why and how you did things, the reasonable judge or jurist will accept those decisions and you’ll be well on your way to making your case.

Aaron is a sergeant with a midwestern police department, where he serves as a trainer, supervisor and SWAT sniper. In addition to his broad tactical knowledge, Aaron has experience in DUI, DRE and undercover narcotics investigations.

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Richard Johnson is a gun writer, police trainer and really bad joke teller. Check out his other writing on sites like Human Events, The Firearm Blog and Police & Security News.

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