Contemporary societies impose non-stop operations, requiring road transport systems to operate around the clock. However, there is an element of the transport system that is not prepared to develop a continuous activity along the day: the human operator. Thus, the conflict between human abilities and the 24h society leads to drivers' fatigue, which is the cause of several road crashes. Driving long distances, alone, and often during the night, represent constraints that are recognised to increase drivers' workload and fatigue.
According to data from the National Sleep Foundation, driver's fatigue and drowsy driving have similar effects to alcohol consumption. Sources of fatigue are related to the task itself and the conditions for its performance in terms of working schedules, day and night shifts, driving distances, the road quality, and the drivers' age.
The road transport system is a very dynamic and complex system involving human-technology interaction and human-technology cooperation with in-vehicle driver assistive technologies, together with numerous social interactions in the traffic. Furthermore, it is totally open, in opposition to other transport modes (railway, maritime, aviation) in which highly trained professionals drive or pilot different vehicles. Within the road transport system, there is an enormous variety of road users.
Three studies about professional drivers' working conditions were developed to identify the individual workload perception, involving 73 bus drivers from urban public transport operators, 156 truck drivers from different operators of the freight industry, and the à priori opinion of a small group of truck drivers about a hypothetic transition from the traditional goods transport towards truck platooning systems.
The technological development brings important improvement to bus and truck drivers' safety: in-vehicle technology supporting the driver (ADAS) and truck platooning, supported by driver-assistive technology and Cooperative Adaptive Cruise Control (CACC), offering potential benefits for safe and efficient travel, together with economic advantages.