Mailing from coast-to-coast sounds like it would take a long time, but there are regular flights cross-country, and the sorting facilities bring mail to the middle of the coast, and then ship it straight across, east or west, depending. This means that the mail has to go first to a central sorting facility.
Truck and bus drivers must generally take a minimum of eight hours off between shifts, and their shift hours are often capped. Airline pilots are required to have 10 hours off between shifts to allow for transportation and rest time.
A worker must not work for more than six hours without a break. An individual who works between six and nine hours is entitled to a minimum rest break of 30 minutes. A 45 minute rest break must be given if an employee works for more than nine hours. The breaks can be split into breaks of at least 15 minutes.