Network Development

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Network Development
Kentucky Model Users Group Meeting
May 27, 2004
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Topics

• Recent Projects
• Approach
• Network Components
• Issues
• Lessons Learned

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Recent TDMs

• County Level Models
• Simpson County (KY)
• Oldham County (KY)
• Hopkins County (KY)
• MPO
• Radcliff / Elizabethtown, KY (Hardin / Meade
  Counties)
• Kingsport, TN (Multiple Counties)
• Nashville, TN (3 Counties)
• Statewide
• Kentucky

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Approach

• Traditional WSA approach in Kentucky
• Download latest ArcINFO file from Kentucky Office
  of Geographic Information (KY OGI)
• http//ogi.ky.gov/data/trans/transdwnld.htm
• (original file has an .e00 extension)

Import the .e00 file into ArcView IMPORT71
Utility

• Export new file into a dynamically segmented
  geographic file

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HIS Data

• Download the latest Highway Information System
  (HIS) Data from the KYTC Division of Planning
  website (concurrent)
• http//transportation.ky.gov/planning/data/his_ex
  tracts/his_extracts.shtm

• (The original data contains an ESRI shapefile,
  BUT only .DBF component is important for this
  process)
• Extract data from each .DBF for the
  county/counties for which model is being
  developed
• Typical data file includes
• RSE_UNIQ
• BEGIN_MP
• END_MP
• Attribute

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Using HIS Data

• Manually combine the data into one spreadsheet
• The mileposts are split as data is added
• Doesnt take as long as you might think!!

• Import the resulting spreadsheet (now a .DBF)
  into ArcView
• Attach the data to the dynamically segmented
  centerline file using ArcView Add Event Theme
  Utility

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Import to TransCAD

• Export the new theme into an ESRI shapefile
• Import new shapefile into TransCAD and convert
  into a standard geographic file (includes node
  layer)
• The file is then cleaned
• False Intersections
• Connectivity Checks
• Extra Nodes / Node Density

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Flowchart (Typical Approach)
Download Line Data
Dynamically Segment
Add Data by Event Theme
Import to TransCAD
Export Shapefile
Download current HIS extracts
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Network Detail

• Philosophy MORE IS BETTER

• So, what does that include?

• All state-maintained (Interstates, Parkways, and
  KY routes)

• What about Locals?

• Yesbut dont always expect the best results when
  assigning!

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Network Detail Other Issues

• Double-Lines?

• Yes, but only Interstates and Parkways.

• Ramps?

• Why not? Great for future air quality analyses.

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HIS Attributes

• Most attributes come from HIS
• Extracts include
• Functional Classification
• Number of lanes / lane width
• ADT / Count Station
• Posted Speed
• ADT typically use current year estimate
• A good idea to review historic trends / last
  count year

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Speed / Capacity

• Speed / Capacity
• Recently have used equations from NCHRP 387
• The calculations are done in Microsoft Excel and
  then attached in TransCAD (join procedure)
• Done for each individual link to better customize
  / increase accuracy

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Other Attributes

• Other issues
• Assigning Direction (manual process)
• Non-HIS routes (general attributes)
• Field visits are recommended
• Differentiate urban / rural routes
• Others?

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Route Systems

• Often, the aforementioned approach does not work
  well
• Statewide Networks?
• Updating Attributes

• The solution Route Systems

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Flowchart (Route System)
Download Line Data
Import to TransCAD / Clean
Create Route System
Attach Data to LRS
Export to Geographic File
Download current HIS extracts
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Centroids

• Automatically generated based on TAZ geographic
  file (i.e., the original centroid is the true
  geographic center)
• Then, each centroid is modified as necessary to
  reflect the center of activity within a zone
• For instance, centroid can be moved based on
  neighborhoods, access roads, aerial photos, etc

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Centroid Connectors

• Automatically drawn at first using TransCAD
  built-in utility (one is added per zone)
• Check each zone individually
• Proper connection
• Good location (aerial? local roads?)
• Modify and Add (as necessary)
• Have developed GISDK tool to add them for the
  KYSTM

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Review Procedures

• Thematic maps (FC, speed, ADT, etc.)
• Internal Review
• Client

• Review Directional Links (one-way, doublelines,
  ramps, etc.)

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Lessons Learned

• Network Development can kill a budget!!

• Easier to subtract roads than add roads!

• Route systems can be a challenge!!

• Dont overuse double lines!