Laserfiche WebLink
LAND USE AND TRAVEL CHARACTERISTICS <br />The central point of each traffic analysis zone (T AZ), where trips begin and end on a <br />transportation planning model network, is called a zone centroid. Zone centroids are at <br />the center of a zone which consists of a variety of land uses bounded by either the <br />roadway network or other geographic or municipal boundaries. The TAZ system was <br />established from a TAZ system originally developed by Kittitas County staff. This T AZ <br />system was revised slightly to disaggregate into smaller zones in the Suncadia and <br />CleElum UGA area. A graphic of the TAZ boundaries is shown as Figure 1. <br />The Kittitas County model consists of two zone types: internal and external. Internal <br />zones were those zones within the model area. Internal zones have associated land use <br />data that is used to generate origins and destinations. External zones were placed along <br />roadways entering and leaving the Kittitas County model area. Land use is not <br />associated with external zones; rather the traffic volumes coming in and out of the area <br />are used to describe the origins and destinations for these zones. <br />During this model update, a number of zones were disaggregated to allow a finer <br />granularity of traffic assignment. The majority of the disaggregated zones were in the <br />areas surrounding Cle Elum. As a part of this zone reorganization, the zone numbering <br />scheme was modified throughout the network to a more intuitive numbering scheme. <br />In general, the zone numbers in each area increase from west to east and from north to <br />south. A record of the old zone numbers can be found within a user-defined attribute <br />of each zone called "OLDZONENO". The new numbering scheme is as follows: <br />~ <br />Zones Area <br />1 to 71 Internal Zones -representing the Ellensburg Area. <br />100 to 179 Internal Zones -representing the Cle Elum-Roslyn Area. <br />200 to 272 Internal Zones -representing the Upper Kittitas County Area <br />excluding zones from the Cle Elum-Roslyn Area. <br />300 to 313 Internal Zones -representing the Lower Kittitas County Area <br />excluding zones from the Ellensburg Area. <br />400 to 461 Internal Zones -representing the Range Area of Kittitas County. <br />1000 to 1004 External Zones -representing the entry/exit points from the model <br />area. <br />Kittitas County, Washington Transportation Model-May 2009 Page23