In Australia and other developed countries, young drivers are more likely to be involved in crashes than older, more experienced drivers. However, not all young drivers are crash involved. There is increasing evidence within road safety literature suggesting the existence of a subgroup of young drivers with an elevated risk of crashing. The aim of this thesis was to examine characteristics of young drivers (aged 16 to 24 years) that identify those with an elevated risk of crash involvement and to validate high-risk driver subtypes among different young driver populations. Young driver interventions might be more effective if tailored to the needs and motivations of these specific subgroups of young drivers identified as being at a higher risk of crash involvement. The first of four studies examined the ability of previous driving behaviour, reflected in driver records, to identify high-risk drivers, that is, drivers deemed culpable for a fatal crash. The official driver records, both crashes and traffic offences, of drivers involved in a multiple vehicle fatal crash were tracked for five years prior to the fatal crash (N=388). This analysis was repeated for a subset of young drivers aged 16 to 24 years (n=82). Although driver records (i.e., prior drink driving offences) had some value in identifying high-risk drivers, they were not useful in identifying the subset of high-risk young drivers. The second study involved an examination of personality characteristics, motivations, driving related attitudes, and behaviours to ascertain whether they could differentiate young traffic offenders (N=336), drivers detected engaging in risky driving, from other young drivers (i.e., university students N=270). Based on a wide variety of questionnaire measures, the profile of characteristics for the offenders indicated that they were well adjusted and generally did not differ greatly from the students. However, there were notable differences on some measures related to aggression. In addition, offenders generally had less safety-oriented attitudes towards road safety issues than students. Considering that young drivers are not a homogenous group, the third and fourth studies examined whether personality characteristics and attitudes could identify different subtypes of young drivers, specifically subtypes with an elevated crash risk. The existence of subtypes was examined and validated among the two young driver populations: university students (N=270) and young traffic offenders (N=336). Based on questionnaire measures, cluster analysis identified four meaningful young driver subtypes in each of the young driver populations. High-risk young driver subtypes were more clearly differentiated among young drivers already identified by their driving record as high-risk (i.e., traffic offenders). Of significance, the high-risk young driver subtypes had a similar profile (i.e., "emotional, hostile" and "thrill-seeking") to those found in previous research. Interventions that matched the needs of these high-risk subtypes were discussed. A 12-month follow up of driver records showed that high-risk subtypes continued to be detected for more traffic offences than other subtypes, and there was a trend of greater crash involvement. It is recommended that further research follow these driver records for a number of years to allow comprehensive validation of these subtypes. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1280851 / Thesis (PhD)-- School of Psychology, 2007