What is the legal standard that allows an officer to stop a vehicle when suspecting impaired driving?

The correct answer is the legal standard of reasonable articulable suspicion. This standard requires that an officer must possess specific and articulable facts that lead them to believe that a person is engaged in criminal activity, such as impaired driving. This standard is less demanding than probable cause, which is necessary for making an arrest. When an officer observes behavior indicative of impairment—such as erratic driving, swerving, or other unsafe maneuvers—they can make a stop based on reasonable articulable suspicion.

The other options represent different legal thresholds. Probable cause is the higher standard required to obtain a warrant or to make an arrest, meaning the officer must have enough evidence to lead a reasonable person to believe that a crime has been committed. Beyond a reasonable doubt is the highest standard of proof used in criminal trials, and Phase 3/Pre-Arrest Screening pertains to specific procedures following an initial stop rather than the legal justification for the stop itself. Thus, reasonable articulable suspicion is the appropriate standard that empowers officers to stop vehicles when suspecting impaired driving.