Qualitative Dimensions of Young Driver Driving Exposure as a Function of Time of Day

Federal Office of Road Safety - Contract Report 148

Abstract:

This report involves the exploration of the qualitative dimensions of young driver driving exposure, and how these differ during the day compared to night-time. Data was collected using two methods: a nationwide door-to-door survey of 3008 drivers, and direct sampling of almost 600 'active' drivers undertaking a trip. Descriptive results are presented for the driving attitudes and behaviours, type of car driven, and personality characteristics of young drivers and a comparison sample of older drivers.

Executive Summary

In the context of their high over-involvement in road crashes, there is relatively little of substance known about specific contributory factors to young driver crashes. One example of this is lack of explanatory information for the riskiness of night-time driving. With a traditional focus on describing the (quantitative) nature of the problem rather than exploring and understanding contributory processes, there has been little progress in specifically improving young driver safety.

There is evidence to indicate that the amount of night-time driving undertaken by young drivers cannot explain their elevated risk of crash involvement at night. When crash frequencies are adjusted for estimated distances travelled by time of day and driver age/experience, night-time driving is a riskier activity for all driver groups, but particularly for young/inexperienced drivers.

What are the contributory factors to this high level of crash risk? On first principles, night-time driving is an inherently more risky activity due to impoverished visual conditions. It seems reasonable to also suggest that qualitative exposure factors may also account for some of the differences in crash risk.

For example, there may be a different 'type' of young driver on the roads at night compared to those who are 'daytime' drivers, reflected by the fact that night-time drivers may do more recreational driving, with a greater number of passengers. Their trips may be more spontaneous than daytime drivers' trips and be in less familiar areas. It may also be that night-time young drivers have different attitudes towards their cars or to driving in general which make them more susceptible to exposure to risky driving situations.

The fundamental aim of the project, therefore was:

"To establish whether there are appreciable differences in the qualitative aspects of driving exposure between young drivers classified as night-time drivers and other young drivers and whether these differences are more marked than for older drivers."

Data on the qualitative dimensions of driving were collected via two methods: a nationwide door-to-door survey of 3008 drivers and a complementary interview survey, co-ordinated with Random Breath Testing activities in two States, of almost 600 'active' drivers interviewed during an actual trip.

As both between- and within-group comparisons were to be made, residential survey respondents in three age groups (<21 years, 21-25 years and 26-50 years) were divided into five independent groups on the basis of their reported exposure. These groups were:

Daytime (D) Group, - those who drove more than the daytime average and less than the night-time average.
Night-time (N, d>n) Group 1, - those who drove less than the daytime average and more than the night-time average, but did more of their driving during the day.
Night-time (N, n>d) Group 2, - those who drove less than the daytime average and more than the night-time average, but did less of their driving during the day.
High Exposure (HE) Group, - those who drove more than the daytime average and more than the night-time average.
Low Exposure (LE) Group, - those who drove less than the daytime average and less than the night-time average.

It is believed that this is the first time that such within-group (and between (age) groups) comparisons have been made and therefore results were presented in great detail. Results of this study have shown that the driving of a designated "night-time" young driver sub-group appears to be qualitatively different in a range of ways. Compared to their proportion of the young driver age group, this sub-group appear:

more likely to be full-time students
less likely to have an annual income over $21,000
less likely to be married
less likely to have children less likely to speak languages other than English at home
less likely to be paying a mortgage
more likely to wear glasses or contact lenses
more likely to drive cars more than 10 years old, display personalised number plates and drive a modified car
more likely to drive their own car
more likely to be under pressure to get to their destination
more likely to be carrying passengers who are friends
more likely to have received one or more warnings in the last 12 months.

When this "night-time driver" young driver sub-group is compared to its "daytime driver" peer group, many of the same differences remain. The differences in reported driving habits, driving assessments and "personality" scales between these sub-groups were generally small.

In addition to specific results, the study also raised some fundamental policy issues on the potential for within group targeting of young driver crash countermeasures. While the qualitative exposure differences are generally not sufficient (in their own right) to justify differential countermeasure attention, it is possible to partition the young driver population into independent groups using a wide range of criteria, of which driving exposure characteristics is but one.

Given this, and an "acceptable" link between these criteria and crash risk, there may be scope to apply different types of countermeasures to sub-groups or differential compliance requirements with the same countermeasure. This would introduce the concepts of countermeasure efficiency and equity into the young driver countermeasure design and evaluation process, in addition to the traditional criterion of effectiveness.