European Regional Science Association ___________________________________________________ August, 2003
• The value of the continuity of transport services (against meteorological conditions,
strikes or any event that can impend the service).
• The value of information on the time attributes of transport services (real time
information on the likely arrival time).
There is also a case that their is a more generic value of time, which corresponds to
the value that economic operators associate to the possibility of having input factor
available at date t. This is a generic value of time with respect to the fact that it
somehow includes all others time dimensions of transportation. This also gives rise to a
conception of transportation services as a way to resolve differentials in the "value" of
goods with respect to space and to time. The existence of transportation arises from
differential in the profitability or marginal utility of a good from one place to another ;
the time dimensions of the transportation services result in turn from the differential of
the value of good at origin and destination from one period to another.
In the current article we will concentrate on the most immediate aspect of time
dimensions which is duration. We recognise that there is a case for studying other
dimension, and that their is a growing interest in reliability, but this goes beyond the
scope of this article.
However focusing on the duration dimension we also find that it is not an
homogeneous concept and that one should take into account different definitions of
transport time. The first one is the travel time, meaning the duration where the vehicle is
actually moving the good from one location to another. But in many instances, this may
represent only a part of the actual duration of transport operations. In many situations
there will be other "delays" between the time the good leaves the shippers' depot and the
time where the good is made available at destination. This will consist for instance in
other logistical operations like cross-docking, intermediate warehousing, grouping -
degrouping, or in other time consuming operations like border-crossing. This defines a
second duration that can be referred to as transportation time. Eventually one could
consider that the shipper and hauliers are also concerned with another duration of the
transportation service. This is the duration between the instant where an arrangement is
made about the transportation of a good and the moment where the good has to be
available for loading. This ordering time added to transportation time can be referred to
as delivery time. One should recognise that the term delivery time may be ambiguous,