ABSTRACT
In Victoria, Australia, flexible pavements founded on expansive soils (that exhibit Gilgai phenomenon) have suffered from excessive roughness and deterioration. This roughness (or loss of shape) typically presents as surface undulations between 5 and 20 m in wavelength, which can be detrimental to the ride quality for large commercial vehicles. It is believed that the presence of roadside vegetation exacerbates Gilgai development and associated roughness within these wavebands. However, at present, no studies have yet quantified the influence of roadside vegetation on the progression of roughness. This paper not only describes the collection of roadside vegetation data but also includes best practice techniques for extracting such data from current geographical information sources. More importantly, this paper analyses this roadside vegetation database against historical road roughness data within specific waveband intervals (over a 12 year period) and presents a model that quantifies the influence of roadside vegetation on such roughness.
