Auditory signs to support traffic awareness

In-vehicle information systems (IVIS) may contribute to increased levels of cognitive workload, which in turn can lead to a more dangerous driving behaviour. An experiment was conducted to examine the use of auditory signs to support drivers´ traffic situation awareness. Eighteen experienced truck drivers identified traffic situations based on information conveyed by brief sounds. Aspects of learning, cognitive demand and pleasantness were monitored and rated by the drivers. Differences in cognitive effort was estimated using a dual-task set-up, in which drivers responded to auditory signs while simultaneously performing a simulated driving task. As expected, arbitrary sounds required significantly longer learning times compared to sounds that have a natural meaning in the driving context. The arbitrary sounds also resulted in a significant degradation in response performance, even after the drivers got a chance to learn the sounds. Finally, the results indicate that the use of arbitrary sounds can negatively impact driver satisfaction. These results have implications for a broad range of developing intelligent transport systems designed to assist drivers in absence of fundamental visual information or in visually demanding traffic situations.