D5 Annex report WP 3: ETIS Database methodology ... - ETIS plus

D5 Annex WP 3: DATABASE METHODOLOGY AND DATABASE USER MANUAL –
FREIGHT TRANSPORT DEMAND
Solutions to these problems are outside the scope of this project and will therefore not be
considered.
The focus will be mainly on change of mode and where possible on entrepot. Transhipment as a
result of change of mode is the best known principle. It is also the easiest to include in transport
chain databases. Entrepot can also be seen as a transhipment action. The difference is the
duration of the transhipment. It would be an added value to include entrepot in a transport chain
structure to be able to preserve the relation between the real origin and the destination.
Including change of mode and entrepot will give a much clearer view on the routes that the
products follow.
How to include Simultaneous Mode Use in the Database?
In figure 5.1 it can be observed that a truck is transported from point C to point D by ship. The
problem that arises in this case is that in fact two modes are being used: road and sea. According
to the classical approach three possibilities exist:
1. Register as road from B to E
2. Register as road from B to C and as sea from C to D and in another record registration as sea
from C to D and as road from D to E
3. Independent registration of flow from B to C as road, C to D as sea and D to E as road
If 1. is used we loose the information that part of the trip was over sea. If 2. is used we loose the
information that the cargo was not transhipped but that the truck was also on the ship. In 3 like
in number 1, the information what type of transhipment takes place is lost. So none of the
possibilities can cope with this Ro ­ Ro situation and the chain structure. These problems can be
solved by using the transport chain concept. Another problem that is solved by using transport
chains is that no double countings can occur when analysing the data.
The same problems of course occur in case a train is transported by ship or a truck is transported
by train. All these possible combinations of modes transported by other modes as ‘simultaneous
mode use’ are defined.
The registration of simultaneous mode use can be solved in several ways:
1. Introduce another mode name for the combination of modes
2. Introduce another variable that indicates whether simultaneous mode use has taken place.
Possibility 1. has as disadvantage that in case we want to know what is actively transported by
ship we have to aggregate several modes.
With possibility 2. this problem is solved. Besides with possibility 2. a strict distinction can be
made between the active mode and the passive mode that is transported.
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27 May 2004