Ride Specification – IRI Update Prepared by Joe Thomas, P.E. 11/1/06 MAAPT 53 rd Annual Asphalt Conference December 6, 2006.
Presentation on theme: "Why is ride important?. Our customers - the driving public values pavement smoothness very high."— Presentation transcript:
Why is ride important?
Our customers - the driving public values pavement smoothness very high
MN/DOT Bituminous Specifications provide the contractor an opportunity to receive an incentive or disincentive payment. The payment is based on an International Roughness Index (IRI) value and whether that segment contains any bumps and/or dips.
During construction season 2006; the International Roughness Index (IRI) was used to evaluate ride.
Impact to Incentive/disincentive dollars? For 652, 0.1 mile segments –Equation A - $215,800 –Table A - $194,245
Impact to Incentive/disincentive dollars? For 195, 0.1 mile segments –Equation B - $19, 325 –Table B- $17,475
Incentive/disincentive dollars? For 635, 0.1 mile segments –Equation C - $58,075 –Table C - $69,650 IRI Equation C pays approximately $0.83 dollars for every $1.00 dollar of Profile Index
2007 Smoothness Device Certification will be held at MnRoad, Albertville, MN
We have found that some software programs were incorrectly calculating the IRI values.
2007 Certificates will be yellow!!
For the 2007 Construction Season Four IRI ride specifications –IRI Equation A – replaces Table A –IRI Equation B – replaces Table B –IRI Equation C – replaces Table C –IRI Percent Improvement – predominately for application on single lift overlays where the existing IRI is greater than 120 in/mile
IRI Equations A, B and C (graphed)
Possible changes for the 2008 Construction Season Speed limit change to less than 42 mph –Currently less than 50 mph IRI in both the right and left wheelpaths –Currently right wheelpath only Segments to be pro-rated on actual length –Currently segments greater than 250 feet treated the same
Possible changes for the 2008 Construction Season Specification written for km or 0.1 miles –now references to 100m or 0.1 miles Areas of localized roughness to replace bumps and dips Operator certification –Use of Proval xx.xx to determine areas of localized roughness
Smoother roads last longer. Any questions of us? Thank you