Table of Contents

2.1 The driving task

Consideration of the requirements of the driving task is fundamental to assessing a person’s medical fitness to drive.

Driving is a complex instrumental activity of daily living. It involves a complex and rapidly repeating cycle that requires a level of skill and the ability to interact with both the vehicle and the external environment at the same time (refer to Figure 1).

The demands of the driving task can vary considerably depending on a range of factors including those relating to the driver, the vehicle, the purpose of the driving task and the road environment (Box 1).

Information about the road environment is obtained via the visual and auditory senses. The information is operated on by many cognitive processes including short- and long-term memory and judgement, which leads to decisions being made about driving. Decisions are put into effect via the musculoskeletal system, which acts on the steering, gears and brakes to alter the vehicle in relation to the road. This repeating sequence depends on:

  • Sensory input
    • vision
    • visuospatial perception
    • hearing
  • Cognitive function
    • attention and concentration
    • comprehension
    • memory
    • insight
    • judgement
    • decision making
    • reaction time
    • sensation
  • Motor function
    • muscle power
    • coordination.

Given these requirements, it follows that many body systems need to be functional in order to ensure safe and timely execution of the skills required for driving. The driver’s sensory, motor and cognitive skills may require detailed assessment to determine the potential impact on driving.

Figure 1: The driving task

Box 1: Factors affecting driving

Driving tasks occur within a dynamic system influenced by complex driver, vehicle, task, organisational and external road environment factors including:

  • the driver’s experience, training and attitude
  • the driver’s physical, mental and emotional health, including fatigue and the effect of prescription and non-prescription drugs
  • the road system, for example, signs, other road users, traffic characteristics and road layout
  • legal requirements, for example, speed limits and blood alcohol concentration
  • the natural environment, for example, night, extremes of weather and glare
  • vehicle and equipment characteristics, for example, the type of vehicle, braking performance and maintenance
  • personal requirements, trip purpose, destination, appointments and time pressures
  • passengers and their potential to distract the driver.

For commercial or heavy vehicle drivers there are a range of additional factors including:

  • business requirements, for example, rosters (shifts), driver training and contractual demands
  • work-related multitasking, for example, interacting with in-vehicle technologies such as a GPS, job display screens or other communication systems
  • legal requirements, for example, work diaries and licensing procedures
  • vehicle issues including size, stability and load distribution
  • passenger requirements/issues, for example, duty of care, communication requirements and potential for occupational violence
  • risks associated with carriage of dangerous goods
  • additional skills required to manage the vehicle, for example, turning and braking
  • endurance/fatigue and vigilance demands associated with long periods spent on the road.