The key to successful rehabilitation is careful planning and programming. Evaluation of the road's condition is the first essential in planning the improvement. If the road is found adequate for present service it should be reevaluated periodically to determine the trend of changes affecting its future adequacy. Such a program provides a continuous inventory, and in this way developing problems can be detected and proper corrective action planned on the most effective basis. Evaluation, which should extend to all roads in the system, includes consideration of geometric adequacy, surface condition, and structural adequacy for current and future use.
Geometric adequacy is evaluated by studying the construction plans, by field inspection, or both.
However, surface condition must be evaluated by field inspection. Structural adequacy is evaluated by studying both surface condition and pavement components, or by measuring pavement deflection. Should the overlay thickness be based on the weakest condition in the section it would be over-designed for the rest of the section, and thus needlessly costly. The proper procedure, therefore, is to correct the weaker areas in advance to provide, as nearly as practicable, a uniform foundation for the overlay. Careful and correct preparation of the existing pavement, prior to the construction of smoothing or strengthening overlays, is essential for good construction and maximal overlay performance.