Worker fatigue from too much overtime has been a concern at transit agencies nationwide after major accidents. In 2004, when a Metro train operator crashed into a train at Woodley Park station, injuring 20 riders, safety investigators blamed a lack of sleep.

The operator was working an overtime shift at the time, his 10th out of the previous 19 work days. In response the National Transportation Safety Board called for requirements to ensure adequate time off between shifts of work.