Road Sign Detection Distance and Reading Distance at an Uncontrolled Intersection

Abstract

A traffic sign needs to be located at a distance that allows drivers to read and understand the message prior to their decision in manoeuvring. The study is aimed at evaluating signs visibility at intersections without traffic lights using the drivers reading distance and detection distance. A total of 35 participants with valid driver's licences were asked to detect and read 6 advance guide signs at an intersection without traffic lights on an urban road. Factors that potentially determine signs readability and visibility such as vehicle's speed, vehicle's travelling time, signs vertical offset and signs letter height which affect signs detection distance and reading distance are analyzed using multivariate regression. The experiment was conducted during night time to present heavier driving and sign reading environment. The positions of the signs were evaluated based on the actual sign positions and the detection and reading distances. Some of the findings include that vehicle travel time, vehicle speed, sign letter height, and sign vertical offset all significantly have a relationship with the sign reading distance whilst sign letter height does not have a significant relationship with the detection distance. The study also evaluated the signs compliance with the applied standards.