The Geography of Transport Systems
Jean-Paul Rodrigue (2017), New York: Routledge, 440 pages.
ISBN 978-1138669574
Maritime Routing Patterns
Authors: Dr. Alexander Kuznetsov and Dr. Jean-Paul Rodrigue
NOTE: This page is no longer updated.
1. Context
The main prevalent feature of contemporary global transportation systems is containerization. Intermodalism, being a logical consequence of containerization, also added to the substantial changes in the landscape of the transport industry, namely by favoring integration between different transport systems. New and ever developing transportation routes appear to be randomly structured. Still, there is a rationale behind this complex behavior.
The main objective of this section is to provide an overview to the interplaying factors shaping the transportation networks and affecting the logistical decision taken when designing a supply chain consisting of different modes. An Excel spreadsheet which contains the data used in this application is available. It contains the different port location patterns, ratios of constant and variable costs, distances and service patterns, vehicle’s capacity utilization.
2. Constraints
These are certain operational costs connected to every vehicle used for cargo transportation. Vehicles have also different cargo capacity, so the unit transportation cost is different for every transportation mode.
Economies of scale are expressed in the alternation of the vehicles’ economy: for short distances the truck is the most cost effective. For medium and long distances rail, then the feeder ship and eventually the ocean ship become more cost effective. All these considerations remain only for fully loaded vehicles. A partially loaded vehicle can substantially change the relative cost effectiveness of transportation modes.
Not only the concrete values, but even the relative levels of costs, capacities and distances can differ greatly. Fluctuations in fuel prices, wages, or financial policies (e.g. a company can increase the mobilization price over real cost), define real operation costs and, eventually, set the effective service range of a mode. Still, these general relationships remain in the real world and are taken into consideration when a transport mode is selected.
It should also be noted that the distance between an origin and a destination is not Euclidian, not even geographical: it is the transport or logistical distance needed to be taken into consideration.
3. Routing Patterns
With all these reservations, propensity to use larger vehicles triggers the rationalization of transportation routes selection. A simplified example helps illustrate how this process works which considers 10 ports of similar size that are located along two maritime facades, evenly spaced along the coastline.
A different pattern of services can be suggested, consolidating all cargo from the façade of departure at one port (hub), delivering it to the opposite hub and distributing to the feeders. This hub-and-spoke routing rationalization gives a better result as the port-to-port pattern.
Transportation costs by land (at the distances of 100 and 200) are lower than by water (see operational costs). This implies that consolidation to the hub port would be more cost effective if performed by trucks or rail. Indeed, this logic serves as a driving force for rationalization of inland transportation. As cargo flows merge into larger ones, the distance between these consolidation centers is set by the threshold of different transport modes. Obviously, the reality deviates from this theoretical framework, since the cargo usually is not evenly distributed, the distances are different, and vessel capacity varies.
In addition, there are alternatives to the hub-to-hub solution. Indeed, with a simple pendulum pattern an ocean ship can call every port of one façade, picking cargo in each port and dropping it in every port of destination facade. At the beginning and ending parts of the voyage (along coastlines) the ocean vessel would not be fully loaded, but these legs are only a small fraction of the whole distance. Using the same cost calculation framework, the costs for this case are almost half of the initial configuration which seems to be more cost effective than the previous solution.
Still, this solution is not correct, since it falls out from the limited reality of our sample. The error in this reasoning is quite clear; the additional costs for calling extra ports on the route as not been taken into account. In the calculation of operational costs it was assumed that the fixed costs components included costs only at two calling ports at each side of the route. Every additional port of call involves additional costs such as towage, pilotage, and dues, which should be taken into consideration. The consideration of additional costs for port calls significantly changes the outcome, but the total costs are still lower than the hub-and-spoke pattern.
Yet another solution can be found by combining pendulum and hub patterns. The loads, distances and coefficients in the examples used in this section were selected to provide that all solutions are equal. Those who wish to explore routing problems in more depth can use the attached Excel spreadsheet to develop different scenarios and their optimal solutions.