An anonymous and uncorroborated tip regarding a possible drunk driver affords officers reasonable suspicion to conduct an investigatory stop. The Supreme Court granted review to consider whether an anonymous and uncorroborated tip regarding a possibly intoxicated highway driver provides a reasonable suspicion sufficient to justify a temporary detention of a driver in order to further investigate. The phoned-in tip here accurately described the vehicle and its location, and related that a possible intoxicated person was “weaving all over.” But, in the brief period the officer observed the vehicle, he saw nothing to indicate that the driver was intoxicated. The Supreme Court held a limited traffic stop was permitted under those circumstances, in order to confirm the officer’s suspicion. The grave risks posed by an intoxicated highway driver justify the minimal intrusion of a brief investigatory traffic stop.