Rural Road Delineation at Night: The Influence of Road-Side Post Location and Frequency on Curve Direction Estimates

Abstract

Previous research has demonstrated the efficacy of road-side posts in providing long term delineation information. In order to explore the role of this type of cue further, an experiment was conducted to evaluate the effect of different road-post configurations on the judgements of curve direction by subjects. Specifically, the effect of positioning posts on the inside only, outside only, or both sides of the curve and the influence of post frequency along the road were examined. A range of road contours and distances to the commencement of curves were included in the experimental stimuli. Static views of rural road scenes were presented to subjects in a laboratory situation, and on each trial they were required to make speeded judgements of whether a right-hand or left-hand curve was presented. The results showed that road-side posts provide significantly better information if they are presented on the outside rather than the inside of the curve. Overall, posts on both sides of the road did not result in faster judgements than posts only on the outside of the curve. Subjects performed better in the higher-frequency post condition than in the lower frequency condition, but there was no marked interaction between the post frequency and post location variables. The findings have implications for the cost-benefits of rural road delineation schemes.