How do you determine if you are subject to the Department of Transportation hours of service limits?

Per IRS Publication 463 the following individuals are subject to the Department of Transportation hours of service limits: 

• Certain air transportation workers (such as pilots, crew, dispatchers, mechanics, and control tower operators) who are under Federal Aviation Administration regulations.
• Interstate truck operators and bus drivers who are under Department of Transportation regulations.
• Certain railroad employees (such as engineers, conductors, train crews, dispatchers, and control operations personnel) who are under Federal Railroad Administration regulations.
• Certain merchant mariners who are under Coast Guard regulations.