The IRS may apply special per diem rates for Meals and Incidental Expenses (M&IE) to workers in the Transportation Industry if, during any single trip away from home, they travel to localities with differing federal M&IE rates.

A Transportation Industry worker is defined as an employee or self-employed individual whose work is of the type that directly involves moving people or goods by airplane, barge, bus, ship, train, or truck, and regularly requires travel away from home.

For 2020, the special transportation industry per diem rate for CONUS (Continental US) M&IE allowance is $66 and the OCONUS (Outside Continental US) rate is $71 as found in the IRS Publication 463.

Per IRS Publication 463 Travel, Gift, and Car Expenses, on page 6:

Using the special rate for transportation workers eliminates the need for you to determine the standard meal allowance for every area where you stop for sleep or rest. If you choose to use the special rate for any trip, you must use the special rate (and not use the regular standard meal allowance rates) for all trips you take that year.

On page 12:

Individuals subject to "hours of service" limits. You can deduct a higher percentage of your meal expenses while traveling away from your tax home if the meals take place during or incident to any period subject to the Department of Transportation's “hours of service” limits. The percentage is 80%.

Individuals subject to the Department of Transportation's “hours of service” limits include the following persons.

• 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.

Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.