Comparing Driving Behaviour between 4WD and Sedan Vehicles:

Vehicle rollover is the most common characteristic of 4WD (4-Wheel-Drive) crashes. Among all fatal crashes in Australia, a significantly higher proportion of 4WD vehicles were involved in rollover crashes compared with passenger cars (35 per cent and 13 per cent respectively) (ATSB, 2001). 4WDs are particularly over-represented in rollover crashes in both high- and low-speed zones (ATSB, 2001). While 4WD vehicles have (on average) different physical characteristics to passenger cars, it is also asserted that driver behaviour plays a role in the differential crash patterns of these vehicles. To our knowledge, no systematic empirical research has been undertaken to examine behavioural factors that contribute to 4WD crashes. The effects of vehicular type on driving behaviour are relatively unexplored. This paper presents the preliminary results of a larger pilot project investigating the behaviour of 4WD vehicle drivers in terms of driving performance on the road as measured with Intelligent Transport Systems (ITS). We compared the vehicle dynamics between 4WD and sedan driving. The study involved experienced drivers (N=16) who drove a 4WD and a sedan on a selected route (24 km) for 30 minutes in Brisbane suburban areas. Both vehicles were fitted with technology which passively measured driver performance characteristics such as following distance, direction of gaze, acceleration and deceleration, lateral forces and vehicle speed. The results showed a tendency for drivers to travel faster in the 4WD, and to decelerate and accelerate more rapidly at a 90 degree turn.