Conclusions
Based on the information provided by the agencies and the results of the analyses, the following conclusions are warranted:
1) For the scenarios evaluated, asphalt rubber is a cost effective alternate for many highway pavement applications.
2) When variability is considered in the inputs (cost, expected life, etc.), the asphalt rubber alternates would be the best choice in most of the applications considered.
3) Asphalt rubber was not cost effective in all applications. LCCA allows one to determine when and where AR will be cost effective.

The results of LCCA are highly dependent on the input variables. Many times these inputs are only best estimates. Every effort is needed to obtain accurate estimates of the average value and expected variability for each input variable. Further, the cost effectiveness of AR is dependent in many of the cases on the ability to reduce thickness when using AR. Without a reduction in thickness, or longer lives for equal thicknesses, the AR alternates would not be cost effective.

Recommendations
Agencies which intend to use asphalt rubber need to consider performing a life cycle cost analysis to determine whether a proposed application is cost effective. As demonstrated in this report, asphalt rubber may not be cost effective for all operations.

A limitation of this study is the lack of good long-term performance data for comparative sections of conventional, polymer modified, and asphalt rubber mixtures. The FHWA pooled fund study, designed to provide this sort of data, was stopped in 1997. This information is still needed if LCCA comparisons between alternates are to be made.