Direct Effects of City Logistics Measures and Urban Freight Demand Models - Sustainable Urban Logistics: Concepts, Methods and Information Systems - page 207

Several city logistics measures can be implemented with a view to reducing the
negative effects of freight transport. As freight flows are generated by restocking
and shopping trips (see the first part of the paper), both these two types of com-
ponents are to be considered.
Furthermore, since the characteristics of urban areas can differ substantially,
city logistics measures have to be specifically designed and assessed in order to
implement the most effective. The choice of a set of city logistics measures (i.e. a
new city logistics scenario) should be based on assessment methodology consisting
of several stages able to highlight different types of effects.
The effects can be classified as internal (i.e. cost variations incurred by the
users of the system, such as retailers, wholesalers, distributors, and carriers) or
external (i.e. incurred by members of the public not directly involved in using the
system; e.g. variations in pollutant emissions, noise, road accidents). Further,
within each of these two classes there may be:
• direct effects, i.e. variations in transportation system costs;
• indirect or second-order effects, mainly variations induced by transport cost
modifications in land use or in the economic system and in the social sphere.
This paper focuses on internal/external direct effects resulting from variations
in network transportation and environmental costs, which are those considered, for
example, in traditional cost-benefit analysis.
In forecasting direct effects, a key role is played by road network simulation
models and a general framework of these models is analyzed in the second part of
the paper. The subsequent section focuses on freight demand models used to
estimate the Origin-Destination (O-D) matrices of freight vehicles, which are used
in road network simulation models, and a review of current models is given, using
a proposed general advanced framework. Further, some upgrading in shopping
demand models is presented. Finally, some conclusions and considerations are
given.
2 Urban Freight Mobility Components
Analyses of urban freight transport traditionally focus only on restocking flows,
i.e. freight vehicle flows from warehouse/distribution centers to trade or service
establishments (e.g. shops, food-and-drink outlets, service activities), and usually
neglect shopping flows. However, some surveys show that purchasing activities
account for about twice or three times the veh-km of deliveries and pick-up
activities. For example, surveys carried out in some European cities on urban
freight mobility (Schoemaker et al. 2006 ; Gonzalez-Feliu et al. 2012 ) revealed that
about 69 % of urban distances (veh-km) covered each day by motorized vehicles
related to freight transport consists of shopping trips, 24 % of restocking trips and
the remaining 7 % results from urban management (e.g. building sites, waste