Worldwide Container Model
L Tavasszy, J van Meijeren, J-F Perrin, A Burgess, A Koike, TNO Mobility & Logistics, NL
1. Networks description
2. The loop between the logistics and assignment models
3. The cases we expect to simulate
The idea of a worldwide container model is to simulate the flows of containers on the maritime network in order to understand how Port choice is done. The maritime network will not be limited to the services provided by carriers, but will take into account plenty of others possible paths. So the model will need to be calibrated in order to conform to the nowadays situation and to identify the routes, where services are provided. For this stage, the hinterland networks will be described very rudely.
The idea is to have an iterative process between the chain choice and the assignment models. First an economical trade model (Atsushi KOIKE?s model) will determine a P/C matrix. Then the logistical model will create an O/D matrix based on chain choice (probit model?), ports costs and links costs. The ports costs are linked to different measures of port efficiency (time, quality, number of services provided by carriers,?) and rates. The links costs are related to the ship size, frequency, rates and other characteristics of the services. When the O/D matrix is created, a SUN assignment will be performed. It will determine the flows of TEU. After that, links costs will be recalculated based on the traffic observed between ports. We assume that if an important flow takes place between two harbors, several services will be provided and/or the ship size will be higher. And as a result, the links costs on this road will be lower. The ship size and frequency will be limited by ports physical characteristics. And finally with this new links costs, another chain choice can be performed. And so on
The loop will end, when the links costs do not vary more than a determined value.
We expect such a model to be able to simulate the effects of a creation of a new harbor or of a modification of one port?s characteristics. The network can also be changed. For example, a path on the polar cap can be created. The O/D matrix can be modified due to GDP evolutions. This will result in a change of flows and maybe of services provided.
Association for European Transport