Abstract:
Road networks are the vital arteries of societies. The need for roads to provide safe and comfortable access and thus contribute to the economic sustainability and environmental protection has been increasing with time. Over the years, engineers have become knowledgeable at optimising resources for maintaining unsealed roads. Numerous manuals and guidelines have been produced, mostly for developed countries with extensive unsealed networks. Some manuals adopt innovative construction and maintenance for the unsealed roads surface layer. The World Bank has commissioned the development of the "Guidelines for Surfacing Alternatives for Unsealed Rural Roads" to assist countries in making surface selections. The guidelines offer detailed discussion on the following: " Summary of current international experience based on literature survey; " Case studies and examples; and, " Development of a decision framework for selecting the most appropriate surfacing under given circumstances. The decision framework was developed to offer guidelines and at the same time to remain flexible enough to be applicable for most circumstances. The framework offers a methodology consisting of a three stage process: 1. Evaluate the need for upgrading on the basis of local environmental and geographic conditions; this step also makes allowance for overriding political or other aspects. 2. Select suitable surface types/ technologies from the presented list. As a result of this step, the user will have a short list of options. 3. Economic and financial analysis techniques are suggested to rank the technically feasible options developed during stage 2. The paper summarizes the guidelines and issues taken account during the decision process of surface technologies.