In search of better route guidance instructions.

Safety concerns have prompted designers of in-vehicle route guidance and information systems (IVRGIS) to make more use of an 'audible interface' to convey guidance instructions. Previous research has shown that, contrary to expectations, detailed guidance instructions can have a detrimental effect upon wayfinding performance, particularly for elderly individuals. In response to these findings a second series of experiments was carried out to try to improve the effectiveness of route guidance. Using the same procedure, 40 male and 40 female drivers aged 18-35 years watched video footage of journeys through an unfamiliar area, while hearing guidance that linked direction instructions to landmarks visible at the decision point. Results showed that those who heard these amended instructions performed significantly better than other groups at a wide range of tasks designed to measure the spatial knowledge that they had acquired. This group performed better than groups who heard nothing, and groups who heard full guidance. The results support the view that, whereas full guidance instructions can have a negative impact upon wayfinding performance, less complex instructions that link landmarks to directions have the capacity to enhance wayfinding performance. This is because instructions of this form strengthen the associations made between directions to be taken and the spatial location of these turns, resulting in the formation of a strong representation of the route. The results also showed that those who had been driving for 1 year or less were significantly less accurate at these tasks than those with more driving experience. This result has important implications for the widespread implementation and use of IVRGIS: suggesting that, for newly qualified drivers, who have not yet developed the ability to attend to and process information while controlling the vehicle, attending to route guidance instructions might have a detrimental effect upon driver safety.