AVS. Arkitektúr verktækni skipulag - 01.12.2004, Side 37

How is it possible to
use the traffic model
differently?
In a given plan it is tested how dif-
ferent parts of the main road net-
work can handle the traffic volume.
The outcome of the traffic model is
then used to predict the traffic vol-
ume on individual roads or links, the
total driven distance, total time trav-
elled, total congestion, and perhaps
fuel usage and pollution from the
traffic. Then the traffic can also be
calculated if you change the plan.
In this way it should be possible to
calculate different possibilities of the
town fabric like increased densities
or other possibilities the planners
would like to investigate. It has
however been somewhat difficult to
carry out such studies as the calcu-
lations have taken much time and
the same applies to investigating
many different development possi-
bilities for all the areas of the district.
A new link
During the last spring semester a
course was held in the Engineering
Department of the University of
lceland on traffic models. A project
connected to this course was to
predict the consequences of add-
ing a new link to the road network
of the Capital Area without altering
anything else in the planning or the
road network of this area. This new
link was a road connection across
Skerjafjörður between Vatnsmýri in
Reykjavík and Vífilsstaðavegur by
Arnarnesvogur. It is however not
certain if it is possible to construct
this link for environmental reasons.
For this reason and with reference
to former studies of tunnelling costs
the construction cost was estimated
2.3 billion. The cost would be higher
if higher demands were made
because of environmental reasons.
Running costs and writeoff costs net
present value roughly equal each
other. The traffic model showed sav-
ings because of different distribution
of the traffic volume and shorter
travel distance and less time and
energy used in the region of 3,1 bil-
lion in net present value. This result-
ed in positive return on investment
of 8,6%. If in addition the reduced
cost, because of fewer accidents
is added, it was estimated that the
saving in net present value would
be 4,8 billion and return on invest-
ment 14,4%. Although this study
was a student project and many
premises taken as given, instead of
being specially researched, e.g. the
construction costs the conclusion
indicates that this undertaking can
result in considerable national eco-
nomic savings.
Conclusion
The traffic model is a powerful
instrument to calculate traffic vol-
umes on the future road network.
The model can also be used to
investigate many choices in the
development of the road system.
Calculating net present value in a
traditional way gives a figure that
can be used to estimate the ben-
efits of adding the link in question to
the traffic network. Of course such
a study does not answer all ques-
tions but none the less it indicates
that this link in the road network of
the Capital Area should be studied
more fully. ■
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