There are a lot of fatigued transportation workers. The U.S. National Sleep Foundation’s 2012 annual Sleep in America poll found that train operators and pilots are the most likely to report sleep related job performance problems.
According to the poll, this might be due to transportation workers not getting the needed 7 to 9 hours of sleep  per night. Many of these workers said their work schedules interfered with getting enough sleep , because they worked too many hours or their shifts occurred during their normal sleep times.
A National Sleep Foundation press release about their poll stated:
“The results of the poll are striking. About one-fourth of train operators (26%) and pilots (23%) admit that sleepiness has affected their job performance at least once a week, compared to about one in six non-transportation workers (17%).
Perhaps more disturbingly, a significant number say that sleepiness has caused safety problems on the job. One in five pilots (20%) admit that they have made a serious error and one in six train operators (18%) and truck drivers (14%) say that they have had a “near miss” due to sleepiness.” 
 Retrieved November 12, 2013, from http://www.sleepfoundation.org/article/how-sleep-works/how-much-sleep-do-we-really-need .
 Retrieved November 12, 2013 from https://www.sleepfoundation.org/wp-content/uploads/2018/10/Graphic-Press-Release-FINAL_0.pdf .