Office of Traffic Safety

A Division of the Minnesota Department of Public Safety

Detection of Impaired Motorcycle Riders

A Resource for Law Enforcement Personnel

The National Highway Traffic Safety Administration has developed a set of fourteen behavioral cues that can be used by law enforcement personnel to accurately detect motorcyclists who are operating their vehicles while intoxicated.

The cues have been labeled as "excellent predictors" and "good predictors" based on study results. The excellent cues predicted impaired motorcycle operation 50 percent or more of the time. The good cues predicted impaired motorcycle operation 30-49 percent of the time.


Excellent Cues (50+ percent probability)

  • Drifting during a turn or in a curve

  • Trouble with dismount

  • Trouble with balance at a stop

  • Turning problems (unsteady, sudden corrections, late braking, improper lean angle)

  • Inattentive to surroundings

  • Inappropriate or unusual behavior

  • Weaving (note that riders will swerve to avoid hazards and often utilize various positions within a traffic lane to be seen by other drivers or to avoid hazards)


Good Cues (30-49 percent probability)

  • Erratic movements while going straight

  • Operating without lights at night

  • Recklessness

  • Following too closely

  • Running a stop light or stop sign

  • Evasion

  • Travelling the wrong way in a lane