Many heavy vehicle accidents occur ____.

Answer: A — between midnight and 6 am

Fatigue and reduced alertness drive a large portion of heavy-vehicle crashes, and these dangers peak during the late-night to early-morning hours. Between midnight and 6 a.m., drivers are more likely to be sleep-deprived, circadian lows make you feel sleepy, and reaction times drop. Darkness also lowers visibility, which makes it harder to notice hazards early and increases stopping distances for big vehicles. That combination—tired drivers, limited visibility, and slower responses—creates a higher crash risk than during other times of day. While accidents can happen at other times, this window shows the strongest link to fatigue-related crashes, making it the best answer.