Traffic Analysis Zone Updates

Changes to TAZ Geometry and Attributes

Major changes were made to the version 9 Traffic Analysis Zones (TAZ), including:

• Internal TAZ were split to increase the model’s geographic resolution.
• TAZ boundaries were modified to better align with underlying land uses and planning boundaries.
• The geographic coverage area was expanded to encompass the entire county for Davis, Salt Lake, and Utah counties. Weber County was expanded up to the ridgeline of the east canyon/mountain areas of the WFRC planning domain but does not include the Ogden Valley area. Box Elder was expanded to encompass up to the ridgeline of the east canyon/mountain areas of the WFRC planning domain.

Figure 1 and Figure 2 show the expanded geographic area and the difference in TAZ boundaries between version 9 and version 8.

Figure 1: Version 9 Expanded Geographic Area

Code

mapTaz = {

  let container = DOM.element('div', { style: `width:${width}px;height:${width/1.6}px` });
  yield container;
  
  let map = L.map(container).setView([40.7608, -111.8910], 8.25);

  let greyLayer = L.tileLayer('https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}{r}.png', {
    attribution: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
  }).addTo(map);

  let lcolors = ['#0000FF'    ,'red'   ]
  let llabels = ['v8.3.2 TAZ' ,'v9.0.0 TAZ'];

  let lyrTAZOld = L.geoJson(geojsonTazOld, { weight: 3.00, color: lcolors[0], fillOpacity: 0}).addTo(map);
  let lyrTAZNew = L.geoJson(geojsonTazNew, { weight: 1.50, color: lcolors[1], fillOpacity: 0}).addTo(map);

  var legend = L.control({position: 'bottomleft'});
    legend.onAdd = function (map) {
      var div = L.DomUtil.create('div', 'legend');
      div.innerHTML = '';
      for (var i = 0; i < llabels.length; i++) {
        div.innerHTML += '<i style="background:' + lcolors[i] + '">&nbsp;</i> ' + llabels[i] + '<br/>';
      }

      // Add CSS style for the background color
      div.style.backgroundColor = 'lightgray';
      div.style.padding = '10px';
      
      return div;
    };
    legend.addTo(map);
}

Figure 2: TAZ Geography Comparison Map

The changes resulted in the addition of 688 internal TAZ. The new internal TAZID range for each county was updated to account for the new zone configuration. A buffer of 54 zones was inserted after the last internal TAZ to allow for future internal TAZ expansion within the max used-zone value.

Table 1: Internal TAZ Comparison

County	v9 Count	v8 Count	Change	v9 TAZID Range	v8 TAZID Range
Box Elder	153	135	18	-152	-134
Weber	428	280	148	-427	-279
Davis	324	231	93	-323	-230
Salt Lake	1311	1127	184	-1310	-1126
Utah	1330	1085	245	-1329	-1084
Total	3546	2858	688	-3545	-2872
Unused Zones	54	0	54	-53	NA

The locations and numbering of the external TAZ gateways were revised to reflect the changes of the expanded internal TAZ coverage area and new internal numbering. The external TAZ numbering was grouped and placed after the internal TAZ and a unused zone buffer. For reference, version 8 external TAZ were ordered by county and shuffled in the internal TAZ range, (e.g. Box Elder externals TAZ following after the Box Elder internal TAZ, Weber external TAZ following the Weber internal TAZ, etc.). The external TAZ changes resulted in the addition of 6 external TAZ. (See Changes to External Location and Numbering for more information on external zones.)

Table 2: External TAZ Comparison

County	v9 Count	v8 Count	Change	v9 TAZID Range	v8 TAZID Range
Box Elder	6	5	1	3601-3606	136-140
Weber	3	3	0	3607-3609	421-423
Davis	0	0	0
Salt Lake	6	7	-1	3610-3615	1782-1788
Utah	14	8	6	3616-3629	2874-2881
Total	29	23	6	3601-3629	137-140, 421-423, 1782-1788, 2874-2881

In addition, the following changes were made to the TAZ shapefile:

• The TAZ UTM NAD83 projection was fixed to use the standard for Utah rather than the ArcGIS default.
• All TAZ boundaries were realigned to county boundaries from the most recent UGRC county dataset.
• All internal TAZ topology was checked and corrected to exclude slivers, gaps, and overlaps.
• External zone polygons (i.e. the arbitrary polygons representing the external zones) were removed in the TAZ shapefile.
• PRKCSTPERM and PRKCSTTEMP fields were updated (see Parking Costs for additional information)
• Large, medium, and small district definitions were updated. There are now 26 large districts, 73 medium districts, and 110 small districts. Medium districts still nest within large districts. Small districts were defined based on city area definitions and do not nest within medium districts. All districts were renamed and no longer include commas in the text string.
• CITY, COUNTY, and EXTERNAL fields were removed. All model scripts referencing CITY and COUNTY were updated to use CITY_FIPS and CO_FIPS.
• A REMM field was added to indicate which TAZs are included in the Real Estate Market Model (REMM), as shown in Figure 3. A value of 1 indicates that the TAZ is part of the REMM area.

Code

L = require('leaflet@1.2.0')
html`<link href='${resolve('leaflet@1.2.0/dist/leaflet.css')}' rel='stylesheet' />`

Code

geojsonTazOld    = FileAttachment("data/tazOld.geojson"   ).json()
geojsonTazNew    = FileAttachment("data/tazNew.geojson"   ).json()

Code

mapTazRemmSpace = {

  let container = DOM.element('div', { style: `width:${width}px;height:${width/1.6}px` });
  yield container;
  
  let map = L.map(container).setView([40.7608, -111.8910], 8.25);

  let greyLayer = L.tileLayer('https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}{r}.png', {
    attribution: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
  }).addTo(map);

  let remmColors = ['#00887F'   ,'#BD0026'       ]
  let remmLabels = ['REMM Space','Non-REMM Space'];
  
  let lyrTAZNew = L.geoJson(geojsonTazNew, {
                            style: function(feature) {
                              var d = feature.properties.REMM;
                              return d==1 ? {color:remmColors[0], weight:1, opacity:0.95} :
                                     d==0 ? {color:remmColors[1], weight:1, opacity:0.95} : 
                                            {color:    '#000000', weight:1, opacity:0.95} ;
                            }
  }).addTo(map);
  
  var legend = L.control({position: 'bottomleft'});
  legend.onAdd = function (map) {
    var div = L.DomUtil.create('div', 'legend');
    div.innerHTML = '';
    for (var i = 0; i < remmLabels.length; i++) {
      div.innerHTML += '<i style="background:' + remmColors[i] + '">&nbsp;</i> ' + remmLabels[i] + '<br/>';
    }

    // Add CSS style for the background color
    div.style.backgroundColor = 'lightgray';
    div.style.padding = '10px';
    
    return div;
  };
  legend.addTo(map);
}

Figure 3: TAZ REMM Space

Changes to TAZ Parameters

The following TAZ-related parameters, located in the0_GeneralParameters.block file, were changed to reflect the version 9 TAZ updates. For comparison purposes, version 8 parameters are also presented.

Used Zones

Table 3: Updated Used Zones

Parameter	v9 Value	v8 Value	Notes
UsedZones	3629	2881	Highest TAZ number used by model

TAZ Ranges

Table 4: Renumbered TAZ Ranges

Parameter	v9 Value	v8 Value	Notes
UsedZones	3629	2881	Highest TAZ number used by model
BoxElderRange	1-153	1-140	Box Elder County Range
WeberRange	154-581	141-423	Weber County Range
DavisRange	582-905	424-654	Davis County Range
SLRange	906-2216	655-1788	Salt Lake County Range
UtahRange	2217-3546	1789-2881	Utah County Range
Dummyzones	3547-3600	2882-3400 (note these are outside of UsedZones)	Placeholder for future TAZ splits
Externalzones	3601-3629	136-140, 421-423, 1782-1788, 2874-2881	External zones
NorthBC	3604-3606	138, 139, 140	North Brigham City external zones

College Zones

Where noted, several colleges were effectively removed from the model in version 9. References to these schools are still in the code base but enrollment was set to zero.

Table 5: Renumbered College Zones

Area	Parameter	v9 Value	v8 Value	Notes
WFRC Colleges	Ensign (was LDSBC)	1029	950	Ensign College
	Westmin	1263	1150	Westminster College
	UOFU_Main	1051	1075	University of Utah - Main
	UOFU_Med	(removed)	1076	University of Utah - Medical
	WSU_Main (was WSU_OGDEN)	437	383	Weber State University - Main
	WSU_Davis	693	525	Weber State University - Davis
	WSU_West	(removed)	290	Weber State University - West
	SLCC_Main (was SLCC_TL)	1580	897	Salt Lake Community College - Main
	SLCC_SC	1231	1126	Salt Lake Community College - South City
	SLCC_JD	1776	1493	Salt Lake Community College - Jordan
	SLCC_Mead	(removed)	1206	Salt Lake Community College - Meadbrook
	SLCC_ML	1886	1516	Salt Lake Community College - Miller
	SLCC_LB	(removed)	989	Salt Lake Community College - Library
	SLCC_HL	(removed)	1294	Salt Lake Community College - Highland
	SLCC_Airp	(removed)	746	Salt Lake Community College - Airport
	SLCC_West	(removed)	745	Salt Lake Community College - Westpointe
	SLCC_HM	(removed)	1607	Salt Lake Community College - Herriman
MAG Colleges	BYU	2939	2384	Brigham Young University - Main
	UVU_Main	2848	2326	Utah Valley University - Main
	UVU_Geneva	(removed)	2280	Utah Valley University - Geneva
	UVU_Lehi (was UVU_THANKP)	2606	2099	Utah Valley University - Lehi
	UVU_Vine	2809	2259	Utah Valley University - Vineyard
	UVU_Payson	3336	2690	Utah Valley University - Payson

Table 6: Updated Colleges (Range)

Parameter	v9 Value	v8 Value
colleges	437, 521, 693, 959, 979, 1007, 1029, 1051, 1085, 1231, 1263, 1491, 1525, 1580, 1776, 1886, 2031, 2606, 2809, 2848, 2882, 2939, 3336	290, 383, 525, 897, 950, 989, 1075, 1076, 1126, 1150, 1294, 1493, 1516, 1607, 2099, 2259, 2280, 2326, 2384, 2690

Zones with Off-line (Exogenous) Trip Tables

Table 7: Renumbered Off-line Trip Table Zones

Parameter	v9 Value	v8 Value
Lagoon	781	562
Airport	965	742

Special Generator Zones

Table 8: Renumbered Special Generator Zones

Parameter	v9 Value	v8 Value
TempleSquare	1035	966
SLC_Library	1147	1015

Removed Parameters

The following TAZ parameters were removed from the general parameters file as they were not being used in the WF TDM:

• RegionRange
• WFRCRange
• MAGRange

Changes to TAZ Input Folder

The following changes were made in the 1_Inputs\1_TAZ folder:

• Added _Source folder which includes the following shapefile datasets:
  • Cities shapefile
  • Counties shapefile
  • Environmental constraints shapefile (just the Wasatch Front model space)
  • Previous version 8.3.2 TAZ
• Added _ViewTAZDistricts folder containing an ArcGIS Pro project with predefined symbology for viewing TAZ and district shapefiles.
• In the Districts folder:
  • Updated the large, medium, and small district shapefiles based on the new TAZ delineations and district definitions.
  • Added new shapefiles representing the Wasatch Front subarea, the REMM area, and super districts.