VAA Virginia Asphalt Fall/Winter 2020

22 FALL/WINTER 2020 THE POWER OF THE CARROT scale calibration to asphalt pump settings. These efforts come with a cost. In a low-bid environment, bonuses allow contractors to incur more upfront costs, anticipating at least recouping those costs with incentives. Is the threshold set at the right value to reward contractors producing a consistent mix—the jury is still out! More evaluation of current and past production data is needed. A cursory review of the 2017–2019 data would suggest a threshold of 0.13, which is approximately the 50th percentile. The goal is to encourage contractors to produce a more consistent mix, understanding the challenges of asphalt plant production. Further evaluation of what is achievable is needed. Conclusion VDOT Senior Leadership has been a long-time proponent of bonuses related to paving. They have recognized the power of the carrot. Starting with rideability in the 1990s, VDOT has strived to reward excep- tional work. Most contractors have benefited through the ride spec incentives, and so has the traveling public with smoother, longer- lasting pavements. With the recent inclusion of density andmix consistency bonus payments, the benefits will be magnified. While the long-termpavement performance data does not yet exist, work by other agencies and researchers has pointed out the long-term benefits and reduced costs to agencies and users. References 2007 VDOT Ride Spec Report (Figure 1) VDOTMaterials Division Presentation to the Paving Leadership Group on August 12, 2020 (Figures 2 and 3) James Gillespie and Kevin K. McGhee, VTRC Report 06-R28 “Impact of Smoothness Incentive-Disincentive on Hot Mix Asphalt Maintenance Resurfacing Costs.” 2006 △ continued from page 21 Most contractors have benefited through the ride spec incentives, and so has the traveling public with smoother, longer-lasting pavements. Cumulative Frequency Standard Deviation 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 2016 excluding pilot 2017 2018 2019 0.00% 0.05% 0.10% 0.15% 0.20% 0.25% 0.30% FIGURE 3: AC Standard Deviation 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 0.05% 0.10% 0.15% 0.20% 0.25% 0.30% FIGURE 4: 2014 MITS PLAID Data