Getting pulled over by a California police officer definitely would rank high on most lists of "things that can ruin someone's day." In fact, such situations have been known to escalate into situations that can threaten a person's career, marriage or life, in general. This is particularly true when a traffic stop results in drunk driving charges.
The more a person understands about state laws regarding such matters, in particular how an individual incident might relate to one's personal rights (or a possible violation thereof), the likelier it is that he or she may be able to avoid conviction if an arrest is made. For instance, many people do not understand the difference between a preliminary alcohol screening device and a Breathalyzer test. However, understanding the difference may impact the outcome of a particular situation.