How to Spot an Impaired Driver

Listed below are cues suggested by the National Highway Traffic Safety Administration as ways to discriminate between impaired and sober drivers.

  • Turning with a wide radius
  • Straddling the center of the road or lane marker
  • Swerving or weaving or abruptly turning away from a generally straight course
  • Driving more than 10 mph below the speed limit
  • Following others too closely
  • Drifting or moving in a straight-line at a slight angle to the roadway
  • The left-hand tires are consistently on the center line or lane marker
  • Erratic braking or stopping inappropriately
  • Signaling that is inconsistent with driving actions
  • Slow response to traffic signals (sudden stop, delayed start)
  • Turning abruptly or illegally
  • Accelerating or decelerating rapidly
  • Driving with headlights off


Contact a law enforcement agency and provide them with the following information:

  • Tell them you wish to report a suspected impaired driver.
  • Give the exact location (road and direction) of the vehicle being driven erratically.
  • Give a description of the vehicle such as model, color, license number.
  • Describe the manner in which the vehicle is being driven.


  • Do not attempt to stop the vehicle.
  • Do not attempt to follow if the vehicle is exceeding the speed limit or any other hazard may exist due to following the vehicle.
  • Do not follow the impaired driver too closely, because he or she may stop suddenly.
  • Do not attempt to detain the impaired driver if he or she should stop.

Do not attempt to act in the capacity of any police, fire or medical person unless you are properly trained and authorized to perform that function.