Application of HDM technology and international good practice in improving long term maintenance planning in Tanzania

TANROADS is in the final stages of implementing a new Road Maintenance Management System (RMMS). At the core of the system is a network information system which holds data on road ordinance, road inventory, road condition, works history and traffic. Following its completion the RMMS will provide a repository for the types of information required to enable TANROADS to be aware of the road assets under its command, and to use this information in developing medium and long term investment programmes using modern decision support tools. In order to address future investment needs and priorities, the HDM-4 planning tool and established appraisal techniques for very low volume roads have been introduced as the decision support elements of the system, and employed in the development of a National Road Maintenance Programme (NRMP). This new capability complements current maintenance planning practices and policies in Tanzania. The configuration and practical application of the RMMS needs therefore to be viewed in terms of supporting TANROADS Business rules. This paper describes the approach taken to configuring and adapting HDM-4, and describes examples of its application in determining appropriate standards, or intervention levels, for maintaining both paved and unpaved roads, and thereafter in applying these in estimating future budget needs and priorities. The approach takes due account of economic considerations in selecting optimum treatment standards, the issue of engineering risk, and road safety and other user considerations. The paper stresses the need for a balanced approach in standards development, and the consistent application of this in planning and subsequent delivery. The special needs of low volume roads have also been addressed through encouraging ‘basic’ accessibility as a fundamental objective. This has required the development and introduction of a number of ‘novel’ planning techniques drawing on practices in Tanzania and internationally.