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The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


Evaluation of Revised Incentive-Only Ride Specification for Asphalt Pavements
Affan Habib, P.E., Michael Wells, P.E., and Bipad Saha, P.E.
Kevin K. McGhee
Kevin K. McGhee
Harikrishnan Nair
Harikrishnan Nair
Year: 2018
VTRC No.: 18-R11
Abstract: In late 2011, the executive leadership of the Virginia Department of Transportation (VDOT) formed an Asphalt Quality Task Force to identify and recommend specific achievable measures to improve the quality of asphalt paving in Virginia. The task force recommended that VDOT assess the feasibility of making an incentive-only provision for ride quality the default for projects that do not qualify for VDOT’s regular specification for rideability, which includes both incentives and disincentives. A pilot application of the incentive-only provision was conducted during VDOT’s 2013 construction season. Although the results indicated no statistically reliable distinction in ride quality between the projects under the incentive-only provision and those with no rideability requirement, the number of sites, VDOT districts, contractors, etc., included in the assessment was limited.

The research summarized through this study addressed a concern that the criteria for the ride specification in the original (2013) incentive-only provision may have failed to reflect quality adequately beyond a limited 52.8 ft (0.01-mi) base length. The study documented the application of an incentive-only provision to a wider range of projects during VDOT’s 2015 construction season. The revised criteria addressed some of the concerns associated with the original criteria. The revised provision maintains the potential for incentives while reducing the likelihood for “accidental” bonuses when the final ride quality is marginal on average but highly variable. Overall, there remains little statistically reliable distinction between the achieved ride quality of projects under the incentive-only provision and of general resurfacing projects with no ride quality requirement. However, based on before and after determinations of the International Roughness Index, greater improvements in ride quality were achieved with the incentive-only pilots (at least in some cases) as compared to sites under no ride quality requirement. The revised incentive-only provision provides a mechanism through which a contractor has an opportunity to recover costs associated with improved practices and perhaps even earn incentives based on good ride quality. It does this while reducing the risk that VDOT will be subject to incentives for otherwise marginal quality work.

The study recommends that VDOT continue to promote and administer an incentive-only provision for qualifying resurfacing activities in accordance with the criteria recommended in this study. However, VDOT should continue to monitor the data from projects under the incentive-only provision and assess the effectiveness and benefit of the revised provision, provided in the Appendix, once it is applied on a larger basis.