Environmental Engineering Reference
In-Depth Information
its international commitments, such as the Kyoto targets and the proposals by the
EU Council for further emission reductions for developed countries beyond the
Kyoto Protocol period (2008-2012).
Despite the above mentioned importance of including GHG emissions as an
impact variable at strategic planning levels, there is a lot of research work still to
be done, in order to improve key methodological issues for their evaluation, as the
research community has not yet developed a unified assessment procedure. This
paper moves one step forward in this direction, with the proposal of a methodology
to assess climate change effects of transport infrastructure plans.
Methodology
The methodology is developed with the support of a Geographical Information
System (GIS), in the following four stages:
Stage 1: Definition of the study area
This stage includes the delimitation of the study area, which includes both the
national territory of the plan under consideration and the cross-border regions in
neighboring countries. The level of aggregation and the zonification is also defined
in this stage. This is needed to select centroids both for the origins (i) and destina-
tions (j) for the accessibility analysis.
Stage 2: Implementation of the transport and socio-economic system in the GIS
In this stage each of the centroids i of the study area defined above is characterized
in terms of its transport and socio-economic data. The transport system is modeled
in a vectorial GIS, resulting in an intermodal graph containing the road and rail
networks. For each arc on the road network, the length, estimated speed according
to type of road and resulting travel time are also recorded (for more details see
[7,
8]
). For the rail mode, each arc is given a commercial speed according to infrastruc-
ture and quality of service characteristics.
Stage 3: Calculation of travel time savings
The approach used to compute travel time savings is based on the calculation of
accessibility indicators, which have a wide potential for their application in strategic
planning processes
[7]
. The selected formulation is for this paper that of the location
accessibility indicator, which computes average travel time to the set of destina-
tions. This indicator was previously used in similar studies at the Spanish national
level
[9]
. The formulation chosen is included in Eq.
1
.
⋅
=
∑
∑
IP
ij
j
L
(1)
i
P
i
j
j
The location indicator (Li) is computed as the average travel time (in minutes) to
the set of destinations, using the population of each destination (Pj) as the weight-
ing variable.
