Driving Seen By Police

Merced DUI arrest

In most cases, you were observed driving and the police justify your stop on the basis of the driving behavior. Your driving behavior can be the most critical factor in the eyes of the jury in deciding your Merced DUI case. The prosecution is sure to wail about your “weaving” or “speeding” or other bad driving behavior to prove the charges.

If they did occur, just how significant are these driving behaviors? Scientific studies conducted by the government demonstrate that these driving behaviors fall statistically well below the level anyone would be expected to equate to proof beyond a reasonable doubt. The National Highway Traffic Safety Administration produced a NHTSA study detection guide which describes a set of behaviors that can be used by officers to detect motorists who are likely to be driving while impaired. A comprehensive knowledge of this “science,” promulgated for the express purpose of DUI detection, is powerful ammunition for your Merced DUI lawyer to use in countering the negative significance of bad driving and may likely support a probability of sobriety.

Police are instructed by the NHTSA Detection Guide as follows:
The driving behaviors identified by the officers are presented in the following four categories:

1) Problems in maintaining proper lane position;
2) Speed and braking problems;
3) Vigilance problems; and
4) Judgment problems.

The cues presented in these categories predict that a driver is DUI at least 35 percent of the time. For example, if an officer observes a driver to be weaving or weaving across lane lines, the probability of DUI is more than 50 percent. However, if the officer observes either of the weaving cues and any other cue listed in this booklet, the probability of DUI jumps to at least 65 percent. Observing any two cues other than weaving indicates a probability of DUI of at least 50 percent, although some cues, such as swerving, accelerating for no reason, and driving on other than the designated roadway, have single-cue probabilities greater than 70 percent. Generally, the probability of DUI increases substantially when a driver exhibits more than one of the cues.

The research suggests that these training materials will be helpful to officers in:

I. Detecting impaired motorists;
II. Articulating observed behaviors on arrest reports; and
III. Supporting officers’ expert testimony.

Amazingly, NHTSA presents a scientific-sounding mathematical formula purporting to establish a calculation of probability that the driver will be DUI. Unwittingly it also establishes a calculation of probability that the driver will not be DUI.

Visit the following two NHTSA websites for detailed analysis on this subject:

https://www.nhtsa.gov/risky-driving/drunk-driving

https://one.nhtsa.gov/Driving-Safety/Impaired-Driving

It may be beneficial in your defense to contrast NHTSA’s calculations with the facts alleged against you. It can be particularly helpful to find out some specific definition as to just what constitutes “weaving,” “drifting,” “swerving,” or “turning with a wide radius.”