Using DUI-Drug Arrests to Enhance Drug Investigations

If you are a narcotics investigator, or just a patrol officer who enjoys working narcotics investigations, you are familiar with this scenario: You make a traffic stop on someone whom you know or suspect is involved in drug activity. You know you are onto something based on the suspect’s demeanor. But you lack probable cause for a search, the suspect denies you consent to search, and a K-9 unit is unavailable. With no other options, you have to let the suspect drive away. Or do you?

An additional option that I think is all too often forgotten is that the suspect is quite possibly driving under the influence of drugs. With additional training in the recognition of drug use, narcotics investigators and patrol officers alike have one more tool in their toolbox for making drug-related arrests. And with an arrest for DUI-drugs comes probable cause for a search and/or a vehicle inventory, depending on your agency’s policies and legal standards. Besides taking a dangerous driver off the streets, these additional arrests can also lead to additional intelligence, informants and possibly search warrants.

This does not mean that you have to be a fully-certified Drug Recognition Expert (DRE). Several training courses now exist nationwide to provide officers with additional training to help recognize drugged drivers. Two of those courses include Advanced Roadside Impaired Driving Enforcement (ARIDE) and Drug Abuse Recognition, offered by Graves and Associates. Completion of these courses will not replace the need for a DRE as part of your investigation, but it will give officers the training they need to better recognize drugged drivers and still proceed with a quality arrest if a DRE is not available.

After attending a drugged driving training course, I am now recognizing symptoms of drug use that I never would have recognized previously. Things that I previously would have either not recognized, or simply attributed to a suspect’s nervousness, I now recognize as a symptom of a particular drug category. This has led to arrests, drugs seized, corroborated information provided by an informant and has further enhanced ongoing drug investigations.

Furthermore, this type of training makes an officer’s testimony much stronger in the courtroom as he/she will be able to better articulate his/her observations and refer to a specific page in a training manual if questioned by a defense attorney. Without this type of training, an officer’s testimony will not be near as strong, and the overall investigation not as thorough.

Legal Issues

In my opinion, one of the keys to making more DUI-drugs arrests is bringing the driver back to your patrol unit during the enforcement period of the traffic stop. This tactic is upheld by Pennsylvania v. Mimm, and a host of other court cases, and increases officer safety. However, officers will want to check with their prosecuting attorney to make sure this practice is accepted. Bringing the driver back to the patrol unit also allows you more time to make many additional observations about a driver’s demeanor, and ask many more questions that you otherwise would not be able to. It is during this time that you can determine whether or not a driver may possibly be under the influence of drugs.

It is important to note some differences between DUI-drugs and DUI-alcohol. Whereas in a DUI-alcohol investigation, all you need to show is that a driver’s blood alcohol level was above .08, that is not necessarily the case with DUI-drugs investigations. Some states have a “Per se” law, which makes it illegal for drivers to have any amount of a prohibited substance in their system. But other states do not have such a law. In these states, DUI-drugs cases can be more difficult to win in court because the prosecutor has to prove impairment as opposed to just showing a certain amount of a prohibited substance. This means that a suspect needs to show numerous signs of impairment, both on field sobriety tests and in general observation. (If you have impaired driving behavior prior to the traffic stop, this makes your case even stronger.)

With an alcohol DUI, the suspect will likely have the odor of alcohol, which will give you more legal authority for further investigation. With DUI-drugs investigations you might have a couple of indicators of drug use without odor. So the sobriety tests should probably occur with the consent of the driver. Thus, if the driver refuses to consent to the sobriety tests, you will likely not have enough probable cause to make an arrest. On the other hand, if the driver is showing several obvious signs of impairment, then that alone can give you the authority to detain the person for further investigation.

Most drug-impaired drivers will not be impaired to the extent that they are stumbling, have slurred speech, etc. My experience has been this: I have stopped a suspect who I was either told was involved in drugs, or who had recently left a suspected drug hangout. During the enforcement portion of the traffic stop I brought the driver back to my patrol unit. During this time period, I observed 1–3 signs that the person was under the influence of drugs. (Also during this time period I ask them if they’ve ever been charged with any drug-related offenses; ever been to drug treatment; and if they have recently used alcohol, illegal street drugs or prescription drugs.)

Free to Leave?

Next comes the most critical point in the traffic stop. I have to make a decision about whether that person is free to leave or not. This determination will be based on the extent of the driver’s impairment and on each officer’s own individual training in drug recognition. If the officer is confident in thier training in drug recognition it is much easier to make the decision that the driver is under the influence of drugs and not free to leave.

On the other hand, if the person is not showing several obvious signs of impairment, and you don’t feel comfortable in your training and ability to recognize the more subtle signs of drug use, then you should probably complete the traffic stop, return all of the driver’s paperwork, and tell him/her they are free to leave. (The point at which a driver feels free to leave and how you ask consent are controversial topics and can vary among jurisdictions and states. Again, officers should check with their prosecutor to see how they want you to handle this.)

You can then ask if they will answer some additional questions and ultimately ask them if they will consent to performing field sobriety tests. After they consent, the impairment will become really noticeable when they start performing field sobriety tests. Their poor performance on the sobriety tests, along with observations of drug use, will establish probable cause to make an arrest, at which point they usually then make some admissions about their recent drug use.

With this in mind, I have had drivers who I could tell had recently been using drugs but did not show enough impairment that I felt confident in saying they were unsafe to operate a motor vehicle. I had no choice but to let them drive away.

Note: Officers must be cautious about becoming greedy and should never arrest a person who is borderline impaired in order to justify a search of the person or vehicle. If the impairment is not extensive, and you think you might have a hard time proving impairment in court, then do not arrest.

Drugged Driving Increasing

While drunk driving is decreasing, drugged driving is increasing. The latest survey conducted by the National Highway Traffic Safety Administration found that drugged driving has increased 16% since 2007, with approximately one in five drivers testing positive for at least one drug in their system. In fact, the number of drivers who tested positive for marijuana has increased by 8.6% since 2007. With the current trend towards marijuana legalization, we can expect that percantage to keep increasing.

With marijuana users about 25% more likely to be involved in a crash, it is more important now than ever before that officers get the necessary training that is required to arrest drugged drivers and successfully prosecute them. And in the process, arresting drugged drivers can further enhance longer-term drug investigations.

MATT ERNST is a Deputy Sheriff who can be reached at

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