There are generally four phases to a DUI investigation: driving, the initial contact, the field sobriety tests, and finally the blood or breath test. In this first part of a four-part series, we will examine how your driving can help or hurt your chances in a DUI defense.
Driving is the first of many clues of intoxication that police officers are trained to look for. In most DUI cases, suspects are either pulled over because of something the officer claims they did wrong, or contacted as a the result of their involvement in an accident.
To prove DUI or Driving While Ability Impaired (DWAI), a prosecutor must persuade a judge or jury that the defendant was less able than ordinary to operate a motor vehicle safely. One of the best pieces of evidence for the fact-finder is the driving of the defendant before police contact.
Usually, DUI suspects are contacted for a traffic infraction, such as failure to remain in a single lane or failure to stop at a stop sign. To legally stop and contact a driver of a motor vehicle, a police officer must have a “reasonable suspicion” that the motorist committed an infraction. The reasonable suspicion can be for something as minor as speeding or a broken taillight. Once the police officer interacts with the driver and perceives signs of impairment, the encounter will quickly turn into a DUI investigation.
Most DUI officers are trained to investigate drunk driving cases founded on materials published by the National Highway Traffic Safety Administration (NHTSA). This federal agency offers “cues” of impaired driving in its training materials. Currently NHTSA recognizes twenty-four cues indicate impaired driving, such as:
• Weaving across lane lines
• Straddling a lane line
• Turning with a wide radius
• Almost striking a vehicle or other object
• Stopping problems (too far, too short, or too jerky)
• Accelerating or decelerating for no apparent reason
• Varying speed
• Slow speed (10+ miles per hour under limit)
• 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 lane for no apparent reason
• Driving without headlights at night
• Failure to signal or signal inconsistent with action
• Following too closely
• Improper or unsafe lane change
• Illegal or improper turn (too fast, jerky, sharp, etc.)
• Driving elsewhere other than the designated roadway
• Stopping inappropriately in response to the officer
• Inappropriate or unusual behavior (throwing, arguing, etc.)
• Appearing to be impaired
NHTSA, US Department of Transportation, DOT No. HS-178 R2/06, DWI (Driving While Intoxicated) Detection and Standardized Field Sobriety Testing VIII (2006).
It should be noted that good driving, or driving without any of these actions, does not mean that the state cannot prove its DUI case. If you have been charged with DUI in Colorado, an experienced defense attorney familiar with the NHTSA training materials can give you the best chance of success.