Effect of driving speed on target visibility under mesopic conditions using a driving simulator

Abstract

This article concerns driving after dark. Control of driving speed, being one aspect of the cognitive load of driving, is an important factor which influences visual performance when driving. However, it is not included as a parameter in the widely used models, such as small target visibility and relative visual performance. A driving simulation platform was established to enable investigation of the effect of driving speed on target detection performance. In addition, the effects of target contrast, position and the initial target appearance distance were also evaluated. The results show that increasing driving speed leads to a significant reduction in both the detection rate and the detection distance. The effect of speed was characterised using the Visibility Level model, by calculating two boundary values of Visibility Level for different speeds. The results show that driving speed has an impact on target visibility. A new model is proposed, the Simulator-based Visual Performance model, the metric for which is the product of detection rate and detection distance. It describes the effect on visual performance of driving speed, target contrast, distance and their interactions. The Simulator-based Visual Performance model predicts the experimental results well.