Upgrading, maintenance and rehabilitation of road infrastructure is expensive, especially in view of the growing scarcity and cost of suitable road building materials. In areas with high mica content and secondary minerals such as smectite in the natural materials, stabilisation with cement is not viable. The Council for Scientific and Industrial Research of South Africa has embarked on a research programme to evaluate the performance of substandard materials improved with anionic nanosilane modified bitumen emulsions for use in base and subbase layers. This work comprises laboratory testing as well as Accelerated Pavement Testing using the Heavy Vehicle Simulator (HVS). The results of a full-scale HVS test on a light pavement as well as initial analysis on a medium traffic road are discussed. It has been shown that stabilisation of available substandard materials using an anionic nano-silane modified bitumen emulsion compared with the standard approach of importing high quality crushed aggregate can lead to savings as high as 40%-50% for equivalent performance. In addition, there was also a significant reduction in construction effort and time.

A cost–benefit analysis method for determining the economic benefits of heavy vehicle simulator testing was evaluated. The University of California and its research partners began conducting accelerated pavement testing in 1994 on behalf of the California Department of Transportation. The authors present the findings of a pilot project intended to define a method suitable for measuring the direct economic benefits of heavy vehicle simulator testing in California. The chosen method was based on a cost–benefit analysis initially developed in Australia and later enhanced and applied in South Africa to determine economic benefits of their respective accelerated pavement testing programs. Results of a case study applying the Australian–South African method to heavy vehicle simulator tests conducted in California are presented. The case study evaluated benefits (in cost savings) from heavy vehicle simulator tests performed to validate innovative pavement mixes and designs proposed for the rehabilitation of a high-traffic urban Interstate route in the Los Angeles, California, area. Although local conditions in these countries differed significantly, the method was successfully applied and consistently showed positive results, presented as discounted net present value and benefit–cost ratio. Sensitivity analysis is recommended to determine a range of savings instead of a single benefit–cost ratio.

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Road condition affects the operations and costs of vehicle using the infrastructure. Various Vehicle Operating Cost (VOC) models provide an indication of road roughness effects on fuel consumption, additional damage to vehicle and tire wear. These models do not include the effect of road conditions on the condition and potential damage of transported freight. These potential damages are mostly limited through the use of improved vehicle technologies or packaging. In the agricultural transportation situation, it is often found that packaging is not a solution to the problem as the use of older vehicle technology operated on mostly rural roads with lower riding quality levels is a main contributor to the problem. This paper evaluates the quantified effects of riding quality on low volume roads on selected damage levels of tomatoes in California. The paper is partly based on a study focusing on Vehicle-Pavement Interaction and its effects on the broader California economy. Vehicle responses to road conditions were measured during operations on a range of rural routes. Laboratory experiments were developed to replicate the dominant vibrations of the trucks, and to measure the stresses that tomatoes typically undergo at these vibration levels. The damage and failure levels for the tomatoes during transportation were determined, and these damage levels used to calculate typical costs to the agricultural suppliers due to road conditions. The problem could thus be quantified, and input data provided for a cost/benefit evaluation of the potential maintenance/improvement of the various routes typically used to transport the tomatoes.Steyn et al.

A pilot study was conducted to determine the direct economic benefits of accelerated pavement testing with heavy vehicle simulators in California. The study discusses the identification and comparison of methods used in various countries to determine the benefits from the research. The study highlights approaches in use since the 1990s, compares alternative methods in a global context, and describes the attributes of an economic evaluation methodology applied to benefits from accelerated pavement testing that was initially developed and used in Australia and subsequently enhanced in South Africa. Promising developments include a toolbox created recently in the United States, consisting of more than 30 measures, in which European and Asian transportation research agencies have expressed substantial interest. The pilot study identified a wide variety of methods at state, national, and international levels and found an emphasis on qualitative benefits. Case studies found that the Australian and South African methodology provided advantages such as quantitative, direct economic benefits (a benefit–cost ratio of around 10:1); an analysis of alternative outcomes; accounting for uncertainty; and validation interviews with implementers of research findings. Challenges identified in using this methodology included intensive cost, labor, and time requirements; sensitivity to assumptions; and subjective input.