Criminal Defense in Orange County

The "Science" of Driving Behaviors

Officers usually stop a motorist for possibly driving under the influence of alcohol based on some driving behavior such as weaving, speeding, or slowing down for no apparent reason. The jury may, in fact, consider your driving behavior as the most important piece of evidence in your DUI case. Forget about that pothole or the fact that you only had an hour of sleep the night before.

Driving behavior has been deemed so important in signaling intoxication that the National Highway Traffic Safety Administration (NHTSA) conducted a study that ostensibly sets scientific standards. Officers use the criteria developed by this test in determining whether a suspect is likely to be a DUI. The NHTSA Detection Guide instructs officers to place questionable driving behaviors into four categories:

  1. Difficulty in maintaining proper lane position
  2. Speed and braking issues
  3. Judgment issues
  4. Problems with looking out for hazards

Each of these is labeled a "cue." These cues predict whether a driver is DUI. The more cues a driver exhibits on the road, the more likely that he is intoxicated. From this scientific "study" training, materials were developed for police officers to detect motorists who are driving under the influence. It also gave them a language for articulating the driving behavior in their reports and in court testimony.

Ironically, the cues that predict DUI drivers can work in favor of the defense. A driver with one "cue," for instance, has a 35% probability of being intoxicated. This suggests that the driver has a 65% probability of not being intoxicated. Different cues generate different percentages, but in no case does a cue or several together produce a 100% probability.

Your Orange County DUI lawyer can use the "scientific" evidence in your favor this way. Moreover, he may want to ask what constitutes "swerving" or "weaving" in the first place, for the study does not make this clear. If you need representation for your DUI case, call the experienced legal team at The Law Office of Barney B. Gibbs for a free evaluation.