DEVELOPMENT OF SOFTWARE FOR ROUTE ASSIGNMENT BY MULTIPLE-PATH TECHNIQUE

Abstract

The object of transportation planning is to plan a transportation network for efficient, comfortable and safe traffic operation at minimal cost. For this at first a set of alternative transport plans for horizon year are generated. Then the operating characteristics of each alternative in the horizon year are estimated in the form of flows in the network and the best alternative is chosen. The transportation planning process relies on travel-demand forecasting, which involves predicting the impacts that various transportation policies and programs will have on travel in urban areas. The subject matter of this study report is the last phase of travel-demand forecasting i.e. route assignment. The choice of routes in the development of transportation network is based on certain parameters like journey time, distance, cost, comfort and safety. Traffic volume on each component of the network is estimated by simulating the volumes on the existing network. Nowadays, so many route assignment techniques are available. But, maximum of them suffer from some drawbacks. Multiple-path route assignment technique conforms to the real life traffic situation and also is accurate. For large road networks, route assignment manually is impossible. After the introduction of high-speed digital computers the task of performing highly iterative procedures can be done easily at a very short time. Keeping the above aspects in view, an user-friendly software for route assignment using multiple-path technique called 'RAMP-2003' has been developed. The source code of the software is written in C++ language. The output is in the form of graphical road network and text also with details like shortest distance from each node to destination, probability of traffic distribution in each link, volume in each link due to individual O-D pair and total volume due to all the O-D pairs. If after assigning traffic to all the links in any link volume exceeds capacity, it makes traffic volume in that link equal to its capacity and re-arranges the traffic in other links until in all the links volumes becomes less than or equal to their capacities. This technique is suitable until volumes in all the links of road network tend become equal to their capacities. After that, measures to increase capacity should be taken. In this software attempts have been done to overcome the drawbacks of `all-or-nothing assignment' and 'capacity restraint technique'.