It is becoming widely acknowledged that fatigue is a critical and pervasive problem in police personnel. This recognition has been driven largely by research on the topic that shows police officers tend to be chronically fatigued and are therefore at a high risk for accident, injury, and error. For example, more than 90 percent of officers report being fatigued a majority of the time, and over a quarter of officers report falling asleep at the wheel within the past month. Police fatigue is particularly concerning for night-shift officers, whose sleep is compromised by having to sleep during the day when their internal clock is pushing them to be awake, causing “circadian misalignment.”