In this paper is presented a summary of the results of work carried out in Australia by the Australian Road Research Board (ARRB) and Melbourne University under ARRB sponsorship. The concept of conspicuity and how it forms part of the process of transferring information to the road user is addressed. The means by which conspicuity hasbeen measured are described together with their strengths and limitations. An experimental program that has advanced the understanding of conspicuity and its usefulness is summarized. The major findings of the experiments are discussed in terms of their practical implications for enhancing the daytime conspicuity of road traffic control devices. The review concludes that the important variables that determine the daytime conspicuity of traffic control devices are the complexity of the background, the size of the object, and its contrast with the immediate surroundings. It was also suggested that there are two distinct components of background complexity, clutter and distraction.(A).
Abstract