1. Minnesota Department of Transportation Mn/DOTs Gradual Shift from Profile Index to IRI

2. Chronology of Shift to IRI 1999: Participated in FHWAs Lightweight Profiler Study, hosting various vendors at MnRoad site Overall, LWP devices involved in study demonstrated moderate repeatability and poor reproducibility

3. Chronology of Shift to IRI 2001: Purchased Ames Lightweight Profiler and ARRB Walking Profiler Began performing random Quality Assurance on projects with ride incentive determined from 0.2 blanking band Profile Index

4. Mn/DOTs Lightweight Profiler

5. Chronology of Shift to IRI 2002: Initiated Profile Index Smoothness Measuring Device Program in spring During QA on job sites, experienced problems replicating contractors 0.2 blanking band Profile Index values

6. Empirical Data: Projects with 0.2 blanking band PI value of 0.0 possessed IRI values ranging from roughly 27 - 42 in/mi Projects with 0.2 blanking band PI value of 1.0 possessed IRI values ranging from roughly 29 - 46 in/mi 0.2 Blanking Band PI vs. IRI

7. Chronology of Shift to IRI 2002 - 2003: Analyzed extensive certification and construction data, finding a very weak correlation between 0.0 and 0.2 blanking band Profile Index results

8. Chronology of Shift to IRI 2005: Let 13 additional bituminous IRI pilot construction projects 2004: Let three bituminous IRI pilot construction projects

9. Chronology of Shift to IRI 2006: Let three concrete IRI pilot projects (results pending) Switched to IRI exclusively on bituminous construction projects Began using Pathways High Speed Profiler for Quality Assurance purposes

10. Mn/DOTs High Speed Profiler

11. Bituminous Ride Incentive Equations

12. Incentive per 528-Foot Segment Bituminous Ride Incentive Equations

13. Bituminous IRI % Improvement Table

14. Incentive/disincentive calculated for each 528-foot segment Payment is based on right wheel path IRI values (9 feet from left stripe) IRI data collected by contractor with certified profiler Bump/dips established with profilograph Ride Incentive Information

15. 2007: Will use IRI exclusively to determine ride incentive for all construction projects Chronology of Shift to IRI

16. Any Questions?