Hello
My colleagues and I are currently in the process of applying an
existing aggregate transport forecast model to a detailed spatial
model (several thousands origins and destinations). We are thus adding
a fourth step (traffic assigment to the network) to a model that
already forecasts origin-destination matrices and modal choice between
zones.
This existing model was written in GAMS, and we would like to keep it
that way.
In the GAMS model library, I have found some models that solve traffic
assigment problems, including Wardropian equilibria.
However, we have found no information how well these algoritms perform
in large-scale problems like the one we consider (quite to contrary,
it has been suggested to us that other algoritms would perform
better).
Does anyone have any experience with this? Does anyone know large
scale traffic assigment models that are in the public domain? If
there are public domain programs written in a different langauge, how
well does the interface with GAMS work?
Thank you in advance.
\
Laurent,
On Thu, Jan 6, 2011 at 5:36 AM, Laurent Franckx wrote:
Hello
My colleagues and I are currently in the process of applying an
existing aggregate transport forecast model to a detailed spatial
model (several thousands origins and destinations). We are thus adding
a fourth step (traffic assigment to the network) to a model that
already forecasts origin-destination matrices and modal choice between
zones.
This existing model was written in GAMS, and we would like to keep it
that way.
In the GAMS model library, I have found some models that solve traffic
assigment problems, including Wardropian equilibria.
However, we have found no information how well these algoritms perform
in large-scale problems like the one we consider (quite to contrary,
it has been suggested to us that other algoritms would perform
better).
It would help you to be a bit more specific. For example, what are
the model types (LP, NLP, MCP) for the various models? What solvers
are you using or do you want information about? The algorithms
mentioned in the previous paragraph are ambiguous.
Also, from your description it sounds like you might have models using
two different solution concepts (optimization and equilibrium) in
mind. Merging them into one model is not a trivial thing. I would
encourage you to start with the smallest case possible - create one if
you must - so you can think about and experiment with how it all fits
together without being burdened by lots of data.
Does anyone have any experience with this? Does anyone know large
scale traffic assigment models that are in the public domain? If
there are public domain programs written in a different langauge, how
well does the interface with GAMS work?
Thank you in advance.
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