Environmental Engineering Reference
In-Depth Information
External scenarios
Policy instruments
Assessment
• User benefits
• Operator costs
• Investment costs
• Emissions
• Accidents
• etc.
Transport policy
instruments
Demographic transition
and growth
Landuse policy
instruments
Car ownership
Household and workplace location
Housing
evelopment model
Household
location model
Time of day model
Transport model
Employment
location model
Land use sub-model
Transport sub-model
Accessibility
Fig. 1
Basic structure of the MARS sub-models
[15]
The MARS model includes a transport model which simulates the travel behav-
ior of the population related to their housing and workplace locations, a housing
development model, a household location choice model, a workplace development
model, a workplace location choice model, as well as a fuel consumption and emis-
sion model. All these models are interconnected with each other and the major
interrelations are shown in Fig.
1
.
The technique of Causal Loop Diagrams (CLD) is used to explain the major
cause and effect relations employed in the model. In the case of car usage, for
example, Fig.
2
shows some of the Casual Loops (balancing and reinforcing casual
loops) that drive the behavior of commuting trips taken by car from one zone to
another. Similar CLDs could be drawn for other modes and for non-commute trips
[17]
. Changes of the fuel prices to the end users influences the attractiveness to use
the car, which will be equilibrated by others CLD as changes on the speed (time)
due to a different level of congestion. Changes on accessibility will modify, in a
long term, the residential and workplace location which may also impact the attrac-
tiveness to car use as well.
Problem Statement - Scenarios
The study was developed by seeking the appropriated CO2 fuel tax level in order
to achieve predefined CO2 emissions targets. Under a disparity duty structure
based on life-cycle emissions, fuels with higher emissions of pollutants and GHG
