In order to explore the selective attention mechanism and the dual-task information-processing model, two experiments were carried out involving a visual search task and a visual detection task. The results showed that the early period of attention selection is controlled in a bottom-up manner. With respect to the dual-task information-processing model, the results showed that the central information-processing model would include a sequence model for tasks that use the same perception resource, causing a bottleneck in information processing. Our study suggests that a simple and prominent signal could be used to attract drivers' attention prior to the emergent events. Moreover, any human-machine interface design in driving-associated systems should consider this information-processing bottleneck. With respect to signal type, targeted and easy to categorize were two useful elements to consider. (c) 2008 Published by Elsevier Ltd.