Technical developments during the last years have made the car as a sensor (or: floating car data) concept a feasible method for collecting data from road traffic. Once this technology is available, the possibility arises to provide the driver of equipped vehicles with accurate and detailed information or advice. This report describes a driving simulator experiment that was conducted to investigate the effects of such in-car information on driving behaviour, taking a queue warning system as a case. A comparison is made among driving with in-car information, with roadside information by means of variable message signs (VMS), and without additional information. In a simulated motorway environment, participants of the experiment were every now and then confronted with a stationary traffic queue. The results show that the queue warning systems all result in the intended changes in driving behaviour when approaching stationary traffic queues. With a queue warning system, the process of speed reduction starts at a larger distance with respect to the tail of the traffic queue, and the occurring maximum decelerations are smaller than without a system. The system results in a increase of the minimum time-to-collision (TTC) in the phase up to the final approach part of the manoeuvre. The behaviour found in the condition with in-car information was closest to the control condition without any pre-warning information. This shows that replacing roadside information with what seems optimised in-car information will not always lead to the same (or better) results in terms of driving behaviour. (A)
Abstract