The effects of information relevancy on driving behaviorA simulator study on professional bus drivers

Bus driving is a complex and cognitively challenging task that places high demands on bus drivers’ working memory. Increasing use of “In-Vehicle Information Systems” leads to driver distraction and is a contributing factor to many road accidents globally, and with systems for tickets, navigation, and timetables, bus drivers are more exposed to this additional workload than other actors in the traffic. This study provides insights into how bus drivers’ driving behavior is affected by auditory traffic information through a driving simulator study at the Swedish National Road and Transport Research Institute. A pre-study showed that many bus drivers in Gothenburg experience that a majority of the messages they receive are irrelevant to them. Difference in driving behavior was identified for conditions in which the drivers received messages irrelevant to their route, which might indicate that irrelevancy is an important factor for the workload imposed to the drivers. We hypothesize that irrelevant messages require processing in the visuospatial sketchpad, which might increase workload more than just auditory information processing. The results of this study implies that the routines for traffic communication between traffic controllers and bus drivers should be considerate, as to reduce the number of irrelevant messages that are cognitively loading the bus drivers.