Understanding and improving temporary road sign stability

Abstract

Temporary road signage is used throughout road networks to regulate traffic and provide warnings to road users. Wind and other factors induce frequent falling of temporary road signage and are a major road safety concern that needs to be addressed. The main aim of this paper was to gain an understanding of temporary road sign stability in the presence of passing road trains and investigate the possibility of stabilising temporary road signage through appropriate design modifications. Simulations and experimental trials were carried out to assess the stability of current temporary road signs used in the industry. This analysis used Ansys Fluent to simulate fluid dynamics in order to infer road sign stability. A field experimental trial was performed in Western Australia’s Pilbara Region using a modified temporary road sign developed based on the outcome of the Ansys simulation. The findings from the simulations showed that the current design is unstable and highly prone to wind induced failure. The simulations suggest that road train transit at 100 km/h is capable of inducing approximately 8 m/s wind velocity in the proximity of the sign, which is greater than that permissible for a rigid sign with no leg mobility. Field trials showed that the modified sign remained stable at 1.2 m from the edge line although it was still prone to falling over at closer distances.