Young Driver Research Program - A review of information on young driver performance characteristics and capacities

Federal Office of Road Safety - Contract Report 129

Abstract:

This report reviews literature on young drivers' behavioural and personal characteristics in relation to their crash risk. Information is discussed within the framework of a theoretical model in which the major determinants of risk are: drivers' personal characteristics (skill, motivation) and their exposure to crash risk (both quantitative and qualitative factors). The review found that young drivers' skills are less developed than those of older drivers; research is required to define the types and amounts of experience needed to become a 'fully skilled' driver; that young driver motivation differs in some important ways from that of older drivers; that decisions made prior to driving influence drivers' subsequent exposure to crash risk, independent of their actual driving performance ' and that there is insufficient evidence to reach any clear conclusion on the issue of the 'young problem driver'.

Executive Summary

This report reviews literature on young drivers' behavioural and personal characteristics in relation to their crash risk. Information is discussed within the framework of a theoretical model in which the major determinants of risk are the interacting effects of two broad categories of factors: drivers' personal characteristics (skill, motivation), and drivers' exposure to crash risk (both quantitative and qualitative factors).

A previous report (Macdonald, 1994a) reviewed literature on patterns of young drivers' crash involvement; such information is useful in understanding the role of distance driven, of some physical environmental factors, and of two basic driver characteristics: age and gender. However, the effects on crash risk of other driver characteristics, particularly driving skills, driving-related motives and associated social factors, are not able to be investigated by means of "crash" literature. These factors are the focus of the present review; findings are summarised below.

Skill-related behaviour

At present there is insufficient evidence to define the types and amounts of experience needed to become a "fully skilled" driver; many recent authors have identified the need for more research on the processes entailed in the development of driving skill.

Young drivers' less developed vehicle control skills are evident in a lower level of control performance; this is reflected in the quality of use of vehicle controls, including the amplitude, duration, velocity and acceleration of control movements. Drivers at earlier stages of development may need to allocate more attention to vehicle control sub-tasks. It appears that vehicle control skills improve rapidly with increasing experience but that their development is incomplete after periods of one to two years, and possibly after considerably longer periods. Evidence on the amount of experience required for the full development of such skills is unclear.

Less-skilled drivers have to devote a greater proportion of their available attentional resources to conscious decision-making and monitoring of their driving, and therefore have a lesser amount of "spare" attentional capacity available. This necessitates different strategies of attention allocation between different aspects of the task, and between task and non-task activities. With increasing driving skill, the development of better cognitive schemata directly reduces the demands on a driver's attentional capacity.

The development of more accurate and detailed schemata of traffic situations means that young drivers' expectancies of "what might happen next" gradually correspond better with reality. Inexperienced drivers show less awareness than older drivers of the actual realities of road system operation in which other road users cannot always be relied upon to follow road laws. Their over-reliance on formal rules or laws appears to reflect the poorer development of their cognitive schemata, on which are based their perceptions and expectations. Consequently, their direction and prioritisation of attentional resources is less well fitted to the contingencies of the driving task.

There are major, skill-related differences between drivers of different levels of experience in the way in which they perceive hazards and risks. "Risk perception" is based on learned experience from which have developed cognitive schemata representing both the external road-traffic environment and the driver's own perceived capacity to avoid potential hazards.

When young drivers underestimate risk, this can be attributed to their not noticing or underestimating the potential danger, and/or to their overestimating their own coping ability. According to one view, subjectively experienced risk reflects the driver's own perceived coping capacity more than it reflects objective risk levels. The driver's perception of his or her own capacity to cope with the expected nature of the driving task and its associated hazards has been shown to influence "risky" driving behaviour.

There is some evidence from the crash literature that young drivers' crash risk is highest during the intermediate phase of skill development. At this stage their imperfect driving skills tend to be combined, particularly in the case of young males, with over-inflated levels of confidence in their own driving skill relative to that of their peers.

Driving at night increases the crash risk of all drivers, but more so for inexperienced drivers because of their less detailed and less accurate expectancies and cognitive schemata. When visual information is degraded as it is at night, speed-related errors become more likely because drivers may inadequately adapt their information acquisition and attention-switching behaviour from that which is appropriate when a greater amount of visual information is available.

Motivational influences on young driver performance

Crash risk is affected by driver motivation as well as by driver skills, and it is clear that young driver motivation differs in some important ways from that of older drivers. The personal goals or motives of young drivers may sometimes conflict with safety-related goals. Young drivers are more likely to speed or drive in similarly "risky" ways, and this tendency has been associated with specifically youthful motives. Some researchers view risky driving by young people as an expression of their "developmental behavioural health syndrome".

Apart from their effects on deliberate risk-taking, some typically youthful motives and values may affect driving performance by altering the ways in which young drivers allocate attention while driving. Thus, young drivers may be less willing than older drivers to modify their driving, for example by driving more slowly, to compensate for other attentional demands.

Motivational factors have a greater influence on the driving performance of young males than females. For example, personal traits such as rebelliousness and "risk taking" have been associated with crash risk among young males but not among young females. Conversely, there is evidence of greater skill-related deficits in young females' driving performance.

However, it is recognised that behaviour such as excessive speeding or manoeuvres such as following too closely, which are objectively risky, might be due not so much to deliberate risk taking or risk acceptance, as to lack of skill in hazard perception and cognition. The higher crash risk of young, inexperienced drivers is seen to be a product of both motivational and skill-based factors.

Factors determining young driver exposure to risk

Decisions made prior to driving influence drivers' subsequent exposure to crash risk, independent of their actual driving performance. In spite of their conceptual

independence, there is evidence of correlations between motivation to drive in a risky fashion, and motivation which increases exposure to risk.

For example, the proportion of a driver's total exposure which occurs at night, when crash risk is higher, is determined by a combination of "lifestyle" and motivational factors which differ according to driver age. Young people drive more at night than older people, they drive less "crashworthy" vehicles, are less likely to be wearing seatbelts (particularly at night), and they carry more passengers.

The "young problem driver" issue

There is evidence of some correlation within the population of young drivers between level of exposure to risk (in terms of the above factors), the "riskiness" of driving performance itself, and personal characteristics such as level of academic achievement and socio-economic status. Some researchers have interpreted such correlations as evidence of a "risky behaviour syndrome", but the low magnitude of correlations casts doubt on their practical significance in the context of road safety.

A related issue is that of the so-called "young problem driver". In this case the main question is not primarily one about the nature of young drivers' characteristic skill deficits or risky behaviours; rather, it is about the distribution patterns of these characteristics within the group of young drivers. At the moment there is insufficient evidence to reach any clear conclusion on this matter.