ABSTRACT
The prime purpose of a pavement is to carry traffic and so its key performance indicator is how well it does that task. This chapter discusses methods for measuring and evaluating the performance of pavements. A pavement may fail to meet expectations in four main ways: by being too rough at a broad focus or locally, by being too slippery, noisy or dusty, or by failing structurally. The short-term negative consequences of any or all of these four factors will be an increase in pavement maintenance and vehicle operating costs and a reduction in road usage. To avoid these problems it will need a stable subgrade, be constructible, be able to carry its intended traffic and be resistant to surficial deterioration. To assess how a pavement performs, it is necessary to be able to measure whole-of-life costs, changes in transverse and longitudinal profiles, changes in surface condition and areas of gross deformation. Before the 20th century, a major traffic concern was that a solid wheel with iron “tyres” could exert very high local pressures on the pavement surface, particularly if that surface was uneven. An otherwise well-constructed pavement would rut in a matter of days. The problem was often exacerbated by the ruts then collecting water which would percolate into the pavement. The ruts also concentrated the vertical loads in a very narrow wheelpath. A single overloaded wheel could totally destroy a length of pavement.
