A Data-Driven Method for Prioritizing Projects in Central Idaho
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Transcript of A Data-Driven Method for Prioritizing Projects in Central Idaho
A Data-Driven Method for Prioritizing Projects in Central Idaho
Prepared for the
2012 ITE Western District Meeting Santa Barbara, California
Prepared by
Bob Schulte, DKS Associates
June 2012
Presentation Outline
1. Development of Corridor Needs Assessment Tool
2. Findings and Conclusions
3. Next Steps
Coverage Area – District 4
Need for Assessment Tool
District 4 Needs
Support was needed for pre-STIP project development process
Dist. 4 had no structured, systematic method for needs identification
Method had to be practical, efficient, and sustainable
ITD Headquarters Requirements
Headquarters grades each district on on-time, on-budget project delivery performance
Corridor Needs Assessment Tool
Corridor Health Tool
STIP Funding Categories
Minor Pavement Preservation (1R)
Pavement Maintenance
Pavement Restoration
Bridge Preservation
Bridge Restoration
Expansion
Highway Safety Improvement
Filtering Factors
Filtering factors are applied prior to calculating need scores
Factors reflect minimum eligibility requirements within each funding program
Example – Minor Pavement Preservation Program
Pavement has not structurally failed, but is not in good structural condition
This means: 2.5 < Cracking Index < 3.5
Identification of Need Score Factors and Weights
Factors needed to reflect:
Requirements from ITD Headquarters for project development
Factors considered by Dist. 4 in their project selection process
Weights:
Initial set of weights developed once factors defined
Weights revised based on Dist. 4 input
Need Score Formula -Pavement Preservation
Factor Weight Formula
HAL? 6.7% =1 if Yes; =0 if No Rutting Depth
13.3% =1/ ((2*Max. Allowable Rutting Depth)/ Rutting Depth) if Rutting Depth>Max. Allowable Rutting Depth; else 0
Pavement Condition
40.0% Interstates and Arterials:
=1 if 2.5<(CI or RI)<3.0; =.33 if 3.0<(CI or RI)<3.5; else 0
Collectors:
=1 if 2.0<(CI or RI)<3.0; =.33 if 3.0<(CI or RI)<3.5; else 0
Daily Truck Traffic
6.7% =Daily Truck Traffic/ Max. Daily Truck Traffic
Speed limit 6.7% =1 if speed limit>65, =.75 if speed limit>55, =.50 if speed limit>35, =.25 if speed limit<35
Interstate? 13.3% =1 if Yes; =0 if No
US Route? 6.7% =1 if Yes; =0 if No
AADT 6.7% =AADT/ Max. AADT for all Dist. 4 segments
Data Sources
Example data sources:
Highway Data Quest (on-line roadway database)
Dist. 4 High Accident Location (HAL) listing
Traffic volume data from ITD Road Section
Bridge data from ITD Bridge Section
WebCARS (on-line crash records database)
Only new data developed was LOS data
System Implementation
Corridor Needs Assessment Tool consists of two components:
Excel spreadsheets for calculating and reporting need scores
GIS shape files for graphically displaying levels of need for highway segments
Need Score Spreadsheet -Pavement Preservation
Need Score Summary
Need Score Map -Pavement Preservation
Segments are color-coded by percentile need category
Gray segments are segments that do not meet filters
Maps allow quick first assessment of highest-need segments
Additional information can be obtained by “drilling down” into spreadsheets
Findings and Conclusions
Corridor Needs Assessment Tool:
Valuable first-cut method for identifying needs by funding category
Provides a systematic, defensible process for establishing project needs
Identified issues:
Data collection more labor-intensive than anticipated
Needs data is static and reflects existing conditions only
Next Steps
Short-term improvements:
Integration of Tool with ITD Transportation Asset Management System (TAMS)
Development of capability to produce future need scores
Long-term improvements:
Variable segmentation of highways for analysis
Linkage of Tool with needs-related databases
Bob SchulteDKS AssociatesTRANSPORTATION SOLUTIONS720 SW Washington Street, Suite 500Portland, Oregon 97205Ph: 503.243.3500 |Cell: 503.504.9086 [email protected] | www.dksassociates.com