What are the initial observations during the vehicle in motion phase (Phase 1)?

The initial observations during the vehicle in motion phase, often referred to as Phase 1, focus on critical behaviors and actions of both the vehicle and the driver. The correct choice emphasizes the importance of observing the vehicle's actions, including its decision to stop and the sequence in which it does so. These observations are crucial because they provide early indicators of potential impairment, such as erratic braking, failure to stop at signals, or a lack of attention to roadway conditions.

In this phase, law enforcement officers watch for specific signs that may suggest the driver is operating the vehicle under the influence of alcohol or drugs. This includes their ability to make proper stop decisions and execute them safely, which can be affected by impairment.

Other options involve relevant aspects of driving but do not capture the comprehensive focus on the actions taken by the vehicle in relation to traffic regulations, which is the essence of initial observations in this phase. Notably, while monitoring traffic signals or facial expressions can provide context, they are not direct indicators of driving behavior and decision-making specific to the vehicle in motion.