What is the primary focus during the vehicle in motion phase of DWI?

The primary focus during the vehicle in motion phase of DWI (Driving While Intoxicated) assessments is on vehicle performance. This involves observing how the vehicle operates in relation to traffic laws and roadway conditions. By monitoring the vehicle's movements, one can identify signs of impaired driving, such as erratic swerving, drifting from lanes, or significant changes in speed that do not correspond with traffic conditions.

Assessing vehicle performance allows law enforcement officers to gather critical evidence needed to determine whether a driver may be under the influence. By focusing on the way the vehicle is being handled, officers can spot behaviors that deviate from safe driving practices, which is a direct indication of possible impairment. Understanding vehicle performance during this phase is vital, as it sets the stage for further evaluations and tests that may be conducted once the vehicle is stopped.