What is the primary decision in Phase 1 of a DWI stop?

The primary decision in Phase 1 of a DWI stop revolves around establishing whether there is probable cause to stop the vehicle. This phase typically begins as an officer observes driving behavior that raises suspicion of impairment, such as erratic movements or violations of traffic laws.

Probable cause is a higher standard than reasonable suspicion; it provides the legal basis for the officer to take action by stopping the vehicle. During Phase 1, officers assess observable cues and decide if further investigation into potential impairment is warranted. Once the stop is made, the focus can shift to observing the driver's behavior in more detail.

Other considerations come into play, such as safety when approaching the vehicle and evaluating the driver's level of intoxication, but they become more prominent in subsequent phases of the encounter. Therefore, determining whether there is probable cause to initiate the stop is the keystone decision in Phase 1.