What is the test for making a brief investigatory stop of a moving vehicle?

Law enforcement officers "may make a brief investigatory stop of a moving vehicle ... if under the totality of the circumstances, they are aware of articulable facts leading to a reasonable or founded suspicion that the person has been, is, or is about to be engaged in criminal activity." Fouche, 776 F.2d at 1402. Traffic violations constitute criminal conduct which provides founded suspicion for a brief investigatory stop. Id. at 1403; see also United States v. Gutierrez-Mederos, 965 F.2d 800, 803 (9th Cir.1992), cert. denied, 61 U.S.L.W. 3583 (U.S. Feb. 22, 1993) (No. 92-6924).