"We will reverse a trial court's disposition of a motion to suppress only if there is, after resolving conflicts in favor of affirmance, insufficient competent evidence fairly capable of supporting the trial court's determination." State v. Kettleson, 486 N.W.2d 227, 228 (N.D. 1992). As we have already observed, a driver's "request for an independent test must be clear and unambiguous."

Additionally, with regard to named and anonymous tips, we have held that the number of tips may increase the quality of the tips. State v. Kettleson, 486 N.W.2d 227, 228 (N.D. 1992) ["When many apparently unassociated people report the same fact, the probability that the fact is true is increased."]. The question arises whether the dispatcher's knowledge of the identity of the informant, not communicated to the investigating officer, may be imputed to the investigating officer for purposes of assessing the officer's grounds for making a stop. If it cannot, then the tip is anonymous for purposes of reasonable-suspicion analysis.

This standard of review acknowledges the significance of the trial court's opportunity to assess the credibility of witnesses and to weigh their testimony. State v. Kettleson, 486 N.W.2d 227 (N.D. 1992). Our recitation of the facts reflects this standard of review.