3. Tactical planning problems
Tactical planning problems deal with optimally utilizing the given
infrastructure by choosing services and associated transportation
modes, allocating their capacities to orders, and planning their
itineraries and frequency. Table 2 and Fig. 3 provide an overview of
the literature discussed on tactical planning problems.
Deciding whether to send cargo direct or through a consolidation
system entails a tradeoff influenced by system costs, operation
times, network structure, and customer requirements. In the literature
on tactical planning problems, mostly hub-and-spoke structures
are regarded. Freight on hub-and-spoke networks is
transported by a single service, or a sequence of services where
the loads are transferred from one service to the next at intermediate
terminals. A service is characterized by its origin, destination,
and intermediate terminals, its transportation mode, route, and its
service capacity. Likewise, a mode is characterized by its loading
capacity, speed, and price. Usually, these services and modes have
fixed costs.