An investigation of characteristics associated with driving speed

Monash University Accident Research Centre – Report #140 - 1998

Authors: W.A. Harrison, E.S. Fitzgerald, N.J. Pronk & B. Fildes

Abstract

Previous research has shown that speed has a clear role in accident causation and injury severity. A model of speed choice, derived from the literature, is presented and explored using data collected from road-side surveys. A relationship was found between drivers' attitudes towards speeding, such as feeling comfortable at high speeds and perceived risk of detection, and their observed speed. Drivers' tolerance of illegal behaviours was also related to speed choice, where those who were tolerant of illegal behaviours drove faster than other drivers.

The characteristics associated with speeding, as defined in this report, can be used to model characters in public education campaigns, such as the Transport Accident Commission advertisements, or to target specific groups of the population as the recipients of education and enforcement campaigns. This report closely follows the methodology used by Fildes, Rumbold & Leening (1991).

Executive Summary

This project is concerned with investigating the factors related to speed choice. Substantial research has linked speed to crash causality and injury severity (Fildes & Lee, 1993; Zaal, 1994; Garber & Gadiraju, 1989), thus it is important to understand which factors influence speed choice in order to reduce the number and severity of crashes. This project aimed to:

collect data relevant to a model of speeding behaviour derived from the literature and to determine its potential validity;
to collect data concerning the general relationship between a number of variables and speed choice; and
to investigate the changes in speed behaviour since a similar project was conducted almost ten years ago (Fildes, Rumbold & Leening, 1991).

The data collection method was similar to that used by Fildes et al. (1991) with the view that comparisons could be made between the two studies. Three of the four sites used in the earlier study were used in this project. These were the Calder Highway, Woodend, Beach Road, Parkdale and Belmore Road, Balwyn. A total of 496 drivers were sampled and surveyed at the road side after covert measurement of their speed.

The key results of the study were:

A factor analysis was performed and observed speed loaded most strongly on the factor which included loadings from most of the speed-attitude related measures. Faster drivers felt more comfortable driving at relatively high speeds, had a history of speeding and believed other drivers were travelling relatively fast. These drivers were also less likely to rate travelling fast as dangerous, were more tolerant towards the range of illegal behaviours included in the survey and they believed themselves to be safer than other drivers.
Observed speed loaded less strongly on two other factors, one relating to age and the other to work-related use of the vehicle at the time of interview. Older drivers tended to drive more slowly, and faster speeds were associated with work-related trips, driving larger cars which were not their own, and relatively high driving exposure.
There was a positive correlation between tolerance of illegal behaviours and observed speed, suggesting that it would be beneficial to conduct further research into the role of moral development or social deviance in speeding behaviour.
Faster drivers considered themselves to be safer than other drivers and reported feeling comfortable at speeds above the speed limit.
No conclusions regarding the effect of increased automated speed enforcement or the Transport Accident Commission public education program could be made with regards to the differences found between the Fildes et al. (1991) study and the current study. A number of potential influences could not be controlled for, including changing economic and demographic factors and changing road conditions, which may have changed the nature of the sample interviewed in the sample.

It was recommended that:

The results could be used to guide character selection in advertising material and/or to define target groups towards which advertising should be directed. Key variables include self-calibration, enforcement attitudes, moral attitudes, speed estimates, personal characteristics and car use.
The potential value of targeting corporate bodies should be investigated as a road safety measure.

Sponsoring Organisation: Baseline Research Program - Department of Justice, Transport Accident Commission, Royal Automobile Club of Victoria (RACV) Ltd, VicRoads.