Probst Law Office, Inc.

Experience You Can Trust

With 19 years of experience, Columbus criminal defense lawyer, and former assistant prosecuting attorney Michael Probst is prepared to defend adults and juveniles accused of a number of crimes. Michael is proud to defend the rights of clients facing charges in mayor’s, state, and federal courts.

OVI / DUI Police Procedure

Police Phases of DUI/OVI Suspicion

Police officers are trained to look for and investigate impaired driving pursuant to a manual published by the National Highway Traffic Safety Administration (“NHTSA”), called DWI Detection and Standardized Field Sobriety Testing (“NHTSA Manual”). The NHTSA manual contains three distinct sections which police officer use in determining whether to arrest an individual for an OVI / DUI offense.

The three NHTSA Manual Sections are:


In the first phase, police officers are trained to observe vehicles in motion in order to determine whether there are visible clues of a possible OVI / DUI violation. In doing so, police officers are trying to determine whether there is sufficient cause to stop a vehicle for suspicion of an OVI / DUI violation or for another traffic offense.

The NHTSA Manual instructs officers on four types of visible clues for a possible OVI / DUI violation:

A. Problems Maintaining Proper Lane Position

  • Weaving
  • Weaving Across Lane Lines
  • Straddling a Lane
  • Swerving
  • Turning With Wide Radius
  • Drifting
  • Almost Striking an Object or a Vehicle

B. Speed and Braking Problems

  • Stopping Problems (too far, too short, too jerky)
  • Accelerating or Decelerating Rapidly
  • Varying Speed
  • Slow Speed (10 mph + Under Limit)

C. Vigilance Problems

  • Driving in Opposing Lanes or Wrong Way on One Way Street
  • Slow Response to Traffic Signals
  • Slow or Failure to Respond to Officer’s Signals
  • Stopping in Lane for No Apparent Reason
  • Driving Without Headlights at Night
  • Failure to Signal or Signal Inconsistent With Action

D. Judgment Problems

  • Following Too Closely
  • Improper or Unsafe Lane Change
  • Illegal or Improper Turn (too fast, jerky, sharp, etc.)
  • Driving on Other Than Designated Roadway
  • Stopping Inappropriately in Response to Officer
  • Inappropriate or Unusual Behavior (throwing objects, arguing, etc.)
  • Appearing to be Impaired
  • Eye Fixation
  • Tightly Gripping the Steering Wheel
  • Slouching the Seat
  • Gesturing Erratically or Obscenely
  • Face Close to the Windshield
  • Driver’s Head Protruding From the Vehicle


In the second phase, police officers are trained to gather face-to-face evidence and determine whether there are sufficient grounds to request an individual to exit their vehicle for further investigation of impairment. In this phase, police officers will spend considerable time observing and interviewing the driver of the vehicle.

Typical investigation clues include:

A. Sight:

Police officers look for things during their observation and interview that are describable clues of alcohol
and/or drug influence, including:

  • Bloodshot Eyes
  • Soiled Clothing
  • Fumbling Fingers
  • Alcohol Containers
  • Drugs or Drug Paraphernalia
  • Bruises, Bumps or Scratches
  • Unusual Actions

B. Hearing:

Police officers listen for things during their observation and interview that are describable clues of alcohol
and/or drug influence, including:

  • Slurred Speech
  • Admission of Drinking
  • Inconsistent Responses
  • Abusive Language
  • Unusual Statements

C. Smell:

Police officers are trained to record evidence of smells that are describable clues of alcohol and/or drug
influence, including:

  • Alcoholic Beverages
  • Marijuana
  • “Cover Up” Odors (Breath Sprays, etc.)
  • Unusual Odors

During the same time that police officers are conducting their post-stop observation and investigation, they routinely ask questions of individuals stopped for an OVI / DUI charge. Police officers routinely administer divided attention tasks by asking for two things simultaneously, asking interrupting or distracting questions and asking unusual questions. In doing so, police officers are looking for a driver’s inability to do two relatively simple things at once, such as answer questions and look for documents requested by the police officers.


During this phase of the OVI / DUI traffic stop, police officers have removed an individual from their vehicle and are poised to administer three psycho-physical (field) sobriety tests:

  • Horizontal Gaze Nystagmus (HGN ) Test
  • Walk and Turn Test
  • One Leg Stand Test

These psycho-physical tests, which are discussed in further detail on this website, are used by police officers on OVI / DUI traffic stops to assess an individual’s mental and physical impairment.

Defense attorney Michael Probst has represented many clients arrested and charged with a Columbus OVI / DUI offense and OVI / DUI offenses throughout Ohio who have challenged police officers’ conduct and administration during the three phases in the NHTSA Manual used by police officers in determining whether to arrest an individual for a DUI / OVI charge. Many OVI / DUI traffic stops are recorded and preserved on police officer cruiser video systems. It is extremely important in every case to review all evidence, including video evidence of traffic stops, to determine whether police have acted appropriately and in substantial compliance with the criteria set forth in the NHTSA Manual. Give us a call to get in touch with a Columbus, Ohio OVI/DUI defense attorney for more information about the entire process.