In People v. Bracken (2000) 83 Cal.App.4th Supp. 1, the defendant was stopped after the officer observed the vehicle weaving within its own lane for approximately one-half mile. The officer initiated a traffic stop and the defendant was charged with driving under the influence. "The officer had five and one-half years' experience and had previously qualified as an expert in cases involving driving under the influence." (Id. at p. Supp. 3.) The defendant appealed, claiming the traffic stop was unlawful and "the trial court erred in finding that reasonable suspicion can be based on a single factor weaving within a lane involving wholly lawful conduct." (Id. at p. Supp. 2.) The appellate division of the superior court disagreed with the defendant's argument. "The officer in this case was an expert in the area of driving under the influence cases. He observed appellant's vehicle weave within its lane for a considerable distance. These facts are sufficient to establish reasonable suspicion." (Id. at p. Supp. 4.)