Most countries have rules restricting the amount of hours a truck or train driver can drive. Virtually all countries have similar restrictions on aeroplane and helicopter piloting hours. Ships have very few restrictions.
The reason for these limits on hours is to reduce the likelihood of driver or pilot fatigue in order to reduce mistakes and make accidents less likely. The only solution to fatigue is sleep. As it is impossible to order somebody to sleep, the crude restriction on vehicle operating hours has been adopted instead.
Restrictions on vehicle operating hours vary from one jurisdiction to another. A common approach is to limit hours within time blocks. For instance, the UK Road Transport (Working Time) Regulations state:
- weekly working time is normally limited to an average of 48 hours
- a maximum of 60 hours work can be performed in a single week, so long as the average 48 hour limit is maintained,
- night workers are restricted to 10 hours working time in any 24 hour period,
- rest breaks must be allowed