City of Greater Sudbury Transportation Study Report

4.2. Traffic Zone Development
The Traffic Zone System developed for the 1992 Transportation Study was reviewed and
used as a starting point for the development of a new traffic zone system for use in the travel
demand-forecasting model. Many zones in the former system were split into two or three
additional zones, which resulted in 130 traffic zones, as shown in Figure 4.2.1.
General guidelines that were used to determine if the existing zones should be split are
detailed in the following sections:
1. Conformance With Census Tract Boundaries
It is important to be consistent with Census Tracts so that traffic zones can be aggregated to
Census Tracts. The rationale being:
It allows comparisons between the Place-of-Residence/ Place-of-Work linkages and the
household survey and assists in ensuring that the household survey data has been
properly expanded; and
It allows the use of POR-POW data in the development of the model.
2. Ability to Model Special Study Areas
The traffic zone system developed for the 1992 Transportation Study did not allow the
modeling of special areas that demonstrate unique trip generation characteristics. This is a
feature that the City wanted included in this transportation study.
3. To Account for Future Development
The new traffic zone system had to account for future development. Several documents
were reviewed to determine where future development could occur. These included active
subdivision plans, Secondary Plans, etc. In order to reflect the anticipated future
development patterns in Chelmsford, Val Caron, Hanmer and the former City of Sudbury,
traffic zones were split in the transportation model.
4. For Accurate Calibration of the Travel Demand Forecasting Model
In some areas, the previous traffic zone system was not detailed enough to properly calibrate
the model and produce reasonable forecasts. This was especially true in the downtown area
and in some of the former municipalities. Generally, the level of detail for the road network in
the model must be similar to the level of detail for the traffic zone system. The traffic zones
in a travel demand-forecasting model are used to load trips onto the road system. Having
too few zones and too many roads or visa-versa will make model calibration difficult and will
produce poor forecasts. To meet the requirements of this Study, the road network, which
has been developed for the model, is reasonably detailed; however further detailing of the
previous traffic zone system was required.
CITY OF GREATER SUDBURY
OFFICIAL PLAN BACKGROUND REPORT
September 2005 Page 39