How Does An Officer Determine Intoxication?

There are three phases to a DUI arrest. These are the vehicle in motion phase, personal contact phase, and pre-arrest screening phase. During the first two phases, the officer is looking for indicators—called cues—of intoxication. The pre-arrest screening phase is where the SFSTs are administered. During the administration of the field sobriety tests, the officer will be checking to see if the suspect is exhibiting clues of intoxication.

Vehicle In Motion Phase

In this phase, the officer first observes the vehicle in operation to notes any initial cues of possible impaired driving. The officer must decide whether there is reasonable suspicion to stop the vehicle, either to conduct further investigation to determine if the driver may be impaired or for another traffic violation.

How Does An Officer Determine Intoxication

The officer’s second task during this phase is to observe the manner in which the driver responds to the signal to stop and note any additional evidence of impaired driving.

There are 24 cues that indicate DUI in the vehicle in motion phase. The officer will be observing the vehicle to see if any of the following occur:

  • Weaving
  • Weaving across the lane line
  • Drifting
  • Straddling a lane line
  • Swerving
  • Almost striking a vehicle
  • Turning with a wide radius
  • Stopping problems
  • Unnecessary acceleration or deceleration
  • Varying speed
  • Driving 10 mph or more under the speed limit
  • Driving without headlights at night
  • Failure to signal or signal inconsistent with the action
  • Driving in opposing lanes or wrong way on one way
  • Slow response to traffic signals
  • Slow or failure to respond to officer’s signals
  • Stopping in the lane for no apparent reason
  • Following too closely
  • Improper or unsafe lane change
  • Illegal or improper turn
  • Driving on other than designated roadway
  • Stopping inappropriately in response to the officer
  • Inappropriate or unusual behavior
  • Appearing to be impaired.

The officer will be trying to see if any of the following cues exist after the stop:

  • Difficulty with motor vehicle controls
  • Fumbling with driver license or registration
  • Difficulty exiting the vehicle
  • Repeating questions or comments
  • Swaying, unsteady, or balance problems
  • Leaning on the vehicle or other object
  • Slurred speech
  • Slow to respond to officer/officer must repeat
  • Provides incorrect information, changes answers
  • Odor of alcoholic beverage from the driver

The following cues are specific to motorcycles during the vehicle in motion phase:

  • Drifting during turn or curve
  • Trouble with dismount
  • Trouble with balance at a stop
  • Turning problems
  • Inattentive to surroundings
  • Inappropriate or unusual behavior
  • Weaving
  • Erratic movements while going straight
  • Operating without lights at night
  • Recklessness
  • Following too closely
  • Running stop light or sign
  • Evasion
  • Traveling wrong way

Personal Contact Phase

The officer’s first task is to approach, observe, and interview the driver while they are still in the vehicle to note any face to face evidence of impairment. During this face to face contact, the officer may administer some simple pre-exit sobriety tests to gain additional information to evaluate whether the driver is impaired. After this evaluation, the officer must decide whether to have the driver exit the vehicle for further field sobriety testing. Once the officer has requested the driver to exit the vehicle, their second task is to observe the way the driver exits and note any additional evidence of impairment.

The following are cues of intoxication that the officer will be looking for during the personal contact phase:

  • Bloodshot eyes
  • Soiled clothing
  • Fumbling fingers
  • Alcohol containers
  • Drugs or drug paraphernalia
  • Bruises, bumps, or scratches
  • Unusual actions
  • Slurred speech
  • Admission of drinking
  • Inconsistent responses
  • Unusual statements
  • Abusive language
  • The smell of alcohol
  • The smell of marijuana
  • The smell of cover up odors
  • The smell of other unusual odors

Pre-Arrest Screening Phase – Administration Standardized Field Sobriety Tests

The officer’s first task in this phase is to administer the SFSTs. If the officer’s agency uses preliminary breath tests (PBTs), their second task would be to administer a PBT to confirm the chemical basis of the suspect’s impairment. Based on these tests and on all other evidence from Phases One and Two, the officer must decide whether there is sufficient probable cause to arrest the subject for DUI or DWI. The entire detection process culminates in the arrest/no arrest decision.

Do I Have To Tell An Officer That I Drank Alcohol Or Took Drugs?

You don’t have to tell an officer that you consumed anything. Admitting to drinking alcohol is one of the cues of intoxication. If you don’t tell an officer that you’ve consumed alcohol, then that’s just one less piece of evidence they have against you.

Admitting to taking drugs can put you in jeopardy of being charged with DUI-drugs—even if the drug you took was legal. Oklahoma’s DUI-drugs law is harsh. If you have any detectable amount of a Schedule I substance, or its metabolites, in your blood, then you’re considered per se guilty of DUI-drugs. This means that you could have last smoked marijuana a month ago and still be found guilty of DUI-drugs if the officer wants to do a blood test on you. You can also be convicted of DUI-drugs if you only took a prescription or over-the-counter medication. If the officer connects impaired driving to your consumption of legal medicine, then you can be charged with DUI-drugs. There is no reason to tell a law enforcement officer what substance you took.

Do I Have To Consent To An Evaluation By A Drug Recognition Expert?

You absolutely do not have to consent to an evaluation by a Drug Recognition Expert (DRE). Officers will try to coerce you into being evaluated by a DRE, but there is no criminal or driver’s license penalty for refusing the DRE evaluation. The more you talk to someone in law enforcement, the more evidence you are giving them. DREs receive training on coercing a defendant to confess. The frequent way DREs “determine” the type of drug someone is on is by that person telling the DRE what they took. A statement by a suspect of what substance they consumed is not helpful in that suspect’s defense.

Source: NHTSA’s 2015 DWI Detection and Standardized Field Sobriety Testing student manual

For more information on How An Officer Determines Intoxication, call (405) 633-3420 to speak with an attorney.