A GUIDE TO TRANSPORTATION MODELING USING TRANPLAN FOR COMPUTER SIMULATION OF STRATEGIES FOR MANAGING THE RURAL ROAD INFRASTRUCTURE. FINAL REPORT

The objective of this research was to develop a methodology to compare the costs and benefits and energy implications of different strategies for managing low volume rural road systems. Both public costs such as construction costs, resurfacing costs and routine maintenance costs, and private costs such as variable vehicle operating costs and driver wages or driver opportunity costs as well as energy implications are considered. Management strategies considered included increasing the miles of hard surfaced roads, reducing maintenance on selected roads and/or road and bridge abandonment. A case study area of approximately 580 sq mi (1502 sq km) was selected in a predominantly agricultural region. Because of the importance of low volume roads to agriculture in the region, special attention was given to the costs of transporting agricultural products and farm inputs on the rural road network. Also considered were personal travel costs and school bus and postal service route costs and overhead traffic. A link-node baseline network was modeled to represent the existing rural road network of the region and all expected agricultural and personal travel. Other link-node networks with different numbers of miles of hard surface roads, reduced maintenance mileage and/or abandoned roads were modeled to represent alternative scenarios. These network models were then solved for the minimum travel cost for all the expected traffic to and from local origins and destinations using a version of the TRANPLAN/NEDS software provided by the Urban Analysis Group. Results show that total annual agricultural and personal travel costs in the study area were $6,704,000, and expected annual maintenance costs were $1,123,000. Paving 27 miles of highly used gravel would reduce farm and local travel costs by $100,000 and overhead travel cost by $75,000 while increasing annualized paving and maintenance costs $187,000. The results of another strategy (abandoning 31 miles of gravel and 135 miles of earth roads) increased farm and local travel costs only $14,000 while decreasing annual maintenance costs $47,000 before salvage. The scenario that combined the two strategies showed a travel costs savings of $166,000 and an increase in annualized paving and maintenance costs of $125,000 before salvage. Vehicle energy consumption declined marginally (less than 1% from the baseline in all scenarios). The application of this type of modeling will enable rural road managers to make rational decisions about expenditures and/or inform the public about the public and private costs and tradeoffs of the rural road network.