Popis: |
The issue of congestion along key arteries to maritime terminals, although common around the world, poses a greater problem in Africa, where growth in freight traffic coupled with poor physical and institutional infrastructure affects logistical efficiency and may be detrimental to economic development. As maritime trade increases in such cities, the problem of congestion on arteries to the port becomes a growing issue and research that supports the effective implementation of congestion mitigation measures in the context of the developing countries become crucial. The use of an inland container terminal connected by rail to a port, termed a 'dry port', is one of the measures employed to reduce congestion in developed port cities such as New York/New Jersey, Los Angeles and Sydney. This solution is vital to developing cities as it, by alleviating congestion on roads, improves freight logistics which can help facilitate economic development. Dry port solutions have previously been classified under three main types - close, mid-range and distant - based on the distance of the inland terminal from the port. This thesis aims to quantify the potential road network benefits of diverting containers to a close dry port located at the rim of a developing port city. It does this by exploring the impact of a single close dry port with varying operational characteristics. These operational characteristics (variables) relate to the container allocation patterns employed and the provision of an Empty Depot Service (EDS) and a Freight Distribution Service (FDS) within the facility. The case of Lagos, Nigeria, is selected for study as it is a developing port city where an increase in freight volume, the location of ports within close proximity to major GDP generators, coupled with poor physical and institutional infrastructure affect logistical efficiency. The research involves developing a container freight traffic model for Nigeria to simulate the current patterns of containerised cargo traffic flows (the reference scenario) as well as that which arises from the introduction of the close dry port solutions (test scenarios). Within this model, the World Bank's HDM IV vehicle operation cost functions are integrated to capture factors that influence freight routing choice in developing countries like Nigeria. The network impact of the containerised cargo traffic patterns derived from the reference and test case scenarios is the output of this model and is measured as the total container-related freight vehicle-km and vehicle-hrs in the road network. This impact is measured for routes to and from the seaports, routes to and from zones in the port city and for the whole system. The output of the test scenario cases are compared to those from the reference case to obtain the relative network benefit of each test scenario. The relative benefits of the dry port with varying characteristics are then compared to obtain results from which the main conclusion are drawn. It is found that a dry port solution with an FDS can provide a container-related freight vehicle-km and vehicle-hrs savings of up to 52% more that a dry port solution without an FDS. On the other hand, the benefit of a dry port solution is found to be significantly less sensitive to the empty depot service variable. Furthermore, the network benefit of a dry port solution is found to be sensitive to the container allocation patterns employed. The close dry port is found to present up to 40% higher benefits by serving only zones closer to the dry port than the seaport. However, the results show that the benefit of the dry port varies depending on the part of the network being accessed. For example, the dry ports with an FDS are shown to provide savings of up to 20% to the system (routes to and from all zones in the country) and up to 39% on routes to and from the port city. However, much higher benefits of up to 78% are observed on routes to and from the seaport. In general, it is found that the network benefit of the close dry port increases almost linearly with increase in dry port usage by up to 80% depending on the services provided within the facility, the container allocation methods employed and the parts of the road network being accessed. The findings contribute to the literature on the impact of dry port characteristics on the efficiency of road networks in developing port cities and can be used to formulate transport policies that address issues of traffic congestion. They present policy makers with insight into the requirements for a dry port solution located at the rim of a port city to reduce congestion and improve the efficiency of the road network. Furthermore, the research highlights some factors which influence freight routing decisions in developing countries that are not normally taken into account in urban freight models and discusses ways of dealing with them. The modelling framework employed shows how it is possible to integrate freight supply chain modelling into urban transport models. The model developed in the thesis can form part of a cost-benefit analysis of individual dry port solutions centred on mitigating congestion in port cities. |