Behavioral Modeling of Urban Freight Transport - Sustainable Urban Logistics: Concepts, Methods and Information Systems - page 225

when used to simulate UGM does not adequately consider the complexity char-
acterizing freight movements at different geographical scales. At the same time,
however, it is appropriate to note that not all researchers in the field univocally
share this view. For different positions one could refer to Sonntag ( 1985 ); Ogden
( 1992 ); Ambrosini et al. ( 2008 ) and the article by Gonzalez-Feliu et al. ( 2013 )in
this topic.
This explanatory deficit is particularly relevant since the M4SA is structurally
not capable of explaining potentially relevant preferences for current scenarios
and, even more important, the possible reactions to policy changes. On the con-
trary, models adopting a behavioral approach (BA) to UGM modeling, repre-
senting only part of the larger disaggregate models set, explicitly consider
stakeholders' utility maximization. 4 BA to UGM presume the researcher is capable
of univocally and correctly identifying key decision makers so to develop an
agent-based micro-simulation approach modeling framework that both describes
and forecasts the behavior of the actors considered (Liedtke and Schepperle 2004 ).
UGM is, according to a copious and qualified group of eminent researchers (Gray
1982 ; Wisetjindawat et al. 2006; de Jong and Ben-Akiva 2007 ; Russo and Comi
2011 ; Filippi et al. 2010 ; Comi et al. 2012 ; Sammi et al. 2009 ; Chow et al. 2010 ;
Roorda et al. 2010 ) an appropriate field of research where the development of
micro agent-based models is most likely going to produce policy relevant results.
In fact, since freight is not moved for its own sake and the underlying motivations
can always be traced back to the profit maximization intent of a given agent,
participating in the process, it appears appropriate to analyze the choices made
according to a well-known and robust theoretical framework that has successfully
been applied in many other fields (also outside transportation) whenever economic
agents' modeling is deemed appropriate.
Different UGM options are influenced, given the derived nature of freight
transport demand, in their relative convenience for each agent-type considered, by
changes in fuel prices, land use patterns and pricing strategies in the markets that
demand freight transport services. It has been suggested (Puckett and Greaves
2009 ) that in order to understand the impacts, measured in terms of the market
outcomes that a policy might produce, one should conjointly consider all the
instruments

policy makers could use and the relevant attributes capable of

affecting agents' freight choices.
Policy makers are intrinsically and structurally interested in knowing, before
implementing a given policy, what the most likely reactions will be in terms of
achievement of the desired objectives. As it will be apparent when discussing the
econometric results ( Sect. 4 ) the research proposed can quantify the WTP for the
possible policies implemented with respect to the reference scenario before
the policy is actually put into action in a real-life context. This paper focuses on

4 In fact, the success or failure of UGM initiatives mainly depends on the reaction of
stakeholders to the implementation characteristics' of policies (see, for instance, Marcucci and
Danielis 2008 ; Paglione and Gatta 2007 ; Danielis and Marcucci 2007 ; Marcucci et al. 2007 ).