Which of the following is a sign of impaired driving?

Constant lane changing is indicative of impaired driving because it often reflects a lack of coordination and control that is frequently associated with intoxication or distraction. Drivers who are impaired may struggle to maintain a steady path, leading them to weave between lanes or make abrupt lane changes. This erratic behavior can stem from difficulties in judgment and depth perception, which are commonly compromised when a driver is under the influence of alcohol or drugs.

In contrast, maintaining a steady speed, properly using turn signals, and following the speed limit are all behaviors typically displayed by a driver who is attentive and operating their vehicle safely. These actions demonstrate good driving practices and awareness of the surrounding traffic conditions, indicating that the driver is likely sober and in control.