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 rjs@dksassociates.com | www.dksassociates.com