70 pages??  It takes only one sentence to say zone boundaries need to be based on access to the network being modeled, period.

Sam Granato
Ohio DOT, Office of Technical Services
1980 W. Broad Street, Columbus, OH  43223
Phone:  614-644-6796, Fax:  614-752-8646
"You will be flogged for being right and flogged for being wrong, but it hurts less when you're right." - Hunter S. Thompson


The Florida DOT has just posted a 70 page report discussing TAZs and
their construction. While the information is for the model users
community in Florida there is a wealth of information in the report that
those who think about such things will find of interest.  The document
is well worth adding to any list of TAZs references that you may have.

The report can be found on the Florida Transportation Modeling web site
at http://www.fsutmsonline.net/index.php?/site/directory/model_docs

The direct link to the report is
http://www.fsutmsonline.net/images/uploads/reports/FDOT_TAZ_White_Paper.pdf