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Sub-Saharan Africa Transport Policy Program (SSATP)
The majority of rural roads and a significant proportion of the main roads in Sub-Saharan Africa are currently unpaved and relatively lightly trafficked. These low-volume roads are important as they impact significantly on the livelihood of the rural population, and are central to sustained socio-economic growth and development. Unfortunately, the poor condition of these roads has acted as a brake on economic development and hindered poverty alleviation efforts.
Unpaved roads generate a continuous cycle of deterioration which requires substantial amounts of replacement gravel — a sacrificial "wasting" layer which is rapidly being depleted in a number of countries, in the process raising serious environmental concerns. Fortunately, there are a number of proven, low-cost bituminous surfacing options that offer economical and sustainable solutions to the gravel road option. In this regard, there is a need to depart from the conventional practice of 'fitting the materials to the specifications' which often renders potentially useful locally available materials unutilized. A new approach of 'fitting the specifications to the materials' will apply a more customized and tailored design corresponding to the local climate, natural materials available in the area, volume and load of the traffic and, in many cases, will economically justify sealing gravel at traffic thresholds of less than 100 vehicles per day as opposed to the conventional approaches that require levels in excess of 200 vehicles per day.
This is the philosophy behind SADC's Guideline for Low-Volume Sealed Roads, developed to capture best regional and international practices in all aspects of provision of Low-Volume Sealed Roads. We should move away from the rigidity of design manuals and specifications that apply to "ideal materials" and adopt and institutionalize guidelines that embrace the use of locally available materials.
Such roads also have a black surface like any bitumen surfaced road. Typically, life-cycle cost savings would be in the order of 30-50 percent over 20 years compared with traditional surface treatments. The reduced cost of construction is achieved through reduced earthworks, reduced haulage distances for construction materials, reduced need for material processing and reduced surfacing costs due to use of locally available materials. Pavement life is also increased due to reduced pavement deflection as pavement layers are compacted to refusal.
The Guideline was developed for SADC by a team of key professionals headed by TRL, and was funded by DFID, Sida and Norad. During SSATP's 2004 Annual meeting in Addis Ababa, member states requested that promotion of LVSR philosophy and dissemination of the Guideline should become a part of the RMF's future work programs. CDs with the Guideline in French, Portuguese and English were distributed in large numbers by the program, and were also made available at SSATP's website (French and Portuguese versions are currently under revision). Regional workshops targeting officials, consultants and contractors were being prepared for 2006, and particular emphasis has been given to expanding the documentation of experiences with such innovative and cost-effective designs.
In 2006, three LVSR workshops have been conducted by SSATP. You may access the reports and presentations from the workshops in the top-right corner of this page. LVSR Guideline links are immediately below. Some presentations in French are available from the French page.
LVSR Guides 1999-2007
LVSR Workshops 2006
SADC Guideline on LVSR