Road outer surface Maintenance Management System is tools for decisions made by managers and experts in order to best execution of repair and maintenance of roads outer surface and reducing costs related to keeping and repairing them. Outer surface Maintenance Management System is a part of united Maintenance Management System foundations of traortation. outer surface Maintenance Management System a conjoined collection from executive performances, data and information, software, techniques and decisions in the field of maintenance and outer surface repairs of roads. HDM system consists of models collection which were designed by global Bank and some world known research Institutes during 18 years research on ways net of some developing country in America, Asia and Africa continents. These models are used as a software with HDM-4. HDM-4 has been designed for comprising of calculating of costs and economical analysis of various selections of investment of Road dept. This software estimates costs for many selections annually during one course of analysis which is determined by a user and regarding fall rate for next costs. Profit rates, present net value and profits of 1 st . year by HDM-4 too. For doing these comparisons, details of investment programs , designing standards, keeping selections and prices of unit , traffic volumes are required for any project and environmental conditions. For any part of road, one model simulate annual, conditions and keeping costs for any selection, speed of automobiles and used sources regarding revenue of automobiles.