2. Transportation
With respect to the environment, transportation is the most visible
aspect of supply chains. Transportation CO2 emissions amount
to some 14% of total emissions, both at global and EU level (Stern,
2006; EEA, 2011). Transportation is also a main source for NOx, SO2,
and PM (particulate matter or fine dust) emissions. McKinnon and
Woodburn (1996), Piecyk and McKinnon (2010) have done studies
of the most relevant factors for CO2 emissions in road transport.
They developed a framework with five types of factors, viz. structural
factors influencing modal split, commercial factors influencing
load factors, operational factors, functional factors and finally
external factors influencing carbon intensity of fuel. Since we also
address other modes of transport in this paper, we will change
their framework somewhat. We examine four choices with respect
to transportation which are supported by Operations Research
models, namely, mode choice (or modal split), use of intermodal
transport, equipment choice and fuel choice. The commercial factors
will be discussed in later sections.