Pavement Asset Management (Aug 1995)

Pavement performance audits have also assisted engineers to analyse vast amounts of data relating to the performance of various traffickable roads in the municipality. Assessing different rehabilitation or reconstruction strategies requires an understanding of the costs and longevity of different pavement types and treatments. Since rigid pavements outlast flexible pavements, the evaluation of various options is based on net present worth. For instance, a flexible pavement life of 20 years and a rigid pavement life of 40 years can be compared on costs only if the appropriate maintenance costs and salvage values are considered on an equal pavement life, ie 40 years. In this economical analysis the discount rate is used to calculate maintenance expenditure at varying ages. In the latest Austroads Pavement Design Guide, the discount factor for public sector project analysis was noted at 10%. Recent analysis by economists The Allen Consulting Group recommended a rate of between 4 and 6%, and the National Road Transport Commission (NRTC) has issued a rate of 5% for road construction.