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Transportation Analysis Zones (TAZ) for the COG/TPB Modeled Region. The TAZ dataset is used to join several types of zone-based transportation modeling data. This version of the new TAZ has been altered slightly to better accommodate the travel demand modeling processes. The transportation-specific version of TAZ3722 is called TPBTAZ3722 and the version applicable for Cooperative Forecasting purposes is called COGTAZ3722.Changes in regional development patterns in population, employment and households, as well as technical advancements in travel demand software warranted a refinement of the COG/TPB Transportation Analysis Zone (TAZ) system. As a result, staff recently completed an update of the TAZ structure. This dataset was updated during 2008-2009 and finalized in July 2009. The prior 2191 zone system was developed in 1995 with the (then) current development patterns, transportation network, and travel demand modeling software limitations all factors in zone configuration and number.Local-level data were the starting point for developing the new zone system. Where local level zones were not available for a jurisdiction, the current COG/TPB zones were used. Significant input from local transportation and planning staff aided in the final product. State-wide county boundary files were obtained from Maryland State Highway Administration (MDSHA) and Virginia Department of Transportation (VDOT); these files were used to create the jurisdictional boundaries for the TAZ layer so as to avoid any discrepancy or preference toward any individual jurisdiction's boundary file. A key objective used during the creation of this most recent TAZ version was to balance the needs of the TPB (with regard to network development/coding and travel demand modeling) and COG's Department of Community Planning and Services (DCPS), the department responsible for providing TPB with the Cooperative Forecasting data. The new TAZ system was developed to address both the present and the future-- what has occurred in the region since the last zone expansion, with respect to the increase and shifts in development, as well as what types of development patterns are being planned for the future. The new zone structure also pays special attention to existing and emerging activity centers, those both regional and local in scale, as well as the location of planned public transportation facilitiesThe new zone structure was designed to be usable and meaningful until the next TAZ update, which has historically been every 10-15 years. The new zone boundaries also align better with street centerlines and local-level TAZ. |