The role of deflection beam surveys in the evaluation of flexible pavements is discussed. Deflection studies in Malaysia and Zambia are described from which a suitable survey method for use on tropical roads, for the purpose of designing strengthening overlays or pavement reconstruction, has been developed. Testing at 100m intervals in both wheel-tracks is recommended with provision for a higher density of testing if the road deflection is variable, if the road surface has areas of visible distress, or if there are occasional very high deflection values. Deflection values of roads tend to exhibit skewed distributions but it is concluded that this is not necessarily a significant factor from the point of view of survey analysis for practical overlay design.

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