This report describes a study jointly conducted by the University of Wyoming and the Wyoming Department of Transportation to examine the effect of construction Profilograph Index (PI) values on long-term roughness measurements of concrete pavements. The objectives of this study were to determine if increased initial pavement smoothness had any lasting effects on the pavement smoothness. The study consisted of selecting 175 test sections in eight different interstate projects, obtaining construction and roughness data, compiling the data in a computerized data base, and conducting statistical analysis. The analysis resulted in the observation that when the initial roughness of concrete sections are less than 7 in. per mile, a slightly rougher section does not necessarily deteriorate faster than a slightly smoother section.

This synthesis will be of interest to administrators, including contract and specifications administrators; research, construction, materials, specification, and design engineers; agency project managers and staff; and highway construction contractors. It describes the state of the practice with respect to the development and present status of performance-related specifications (PRS) for highway materials and construction. This report of the Transportation Research Board summarizes the historical events that have prompted U.S. interest in PRS development and describes the underlying concepts. In addition, it describes current practice with regard to PRS implementation and refers to the principal PRS literature with emphasis on performance and cost models. It emphasizes the utility of PRS in providing objective/ rational measures that can be used for special contract conditions, such as incentive or disincentive adjustments.

Smoothness, the absence of bumps and dips in the riding surface of a pavement, improves the quality of the ride and is believed to prolong the life of the pavement. This research addressed the impact of potential pay adjustments for smoothness on maintenance contract prices for hot-mix asphalt. In addition to the construction costs associated with potential incentives/disincentives for smoothness, the research examined the financial value of the resulting product (presumably smoother pavements). The analysis included maintenance cost savings for the owner/agency, as well as any reduction in delay and operating costs for the motoring public. A detailed statistical analysis of 5 years of Virginia's plant mix resurfacing schedules found no statistically definitive impact on bid price as a result of the Virginia Department of Transportation's (VDOT) special provision for rideability for asphalt pavements. A similar analysis on a more focused data set, however, did document a lifetime reduction in the International Roughness Index (IRI) of almost 9 in/mi. This reduction in roughness (increase in smoothness) implies an increase in pavement service life, which translates into reduced annual maintenance costs. Although the analysis supports as much as 7 years in additional functional life, an example calculation demonstrates that just a 2-year life extension will supply approximately $1,295 (about 6% of material costs) in owner/agency savings for every lane-mile of highway that is resurfaced under the special provision for rideability. If VDOT continues to employ the special provision with the frequency it has averaged over the past 4 years (1,033 lane-miles per year), using the special provision will save on the order of $1.3 million per year. The lifetime decrease in roughness can lead to even more dramatic user cost savings. One real example provided in the report demonstrates a fuel cost savings (for trucks alone) of $160,000 over a 10-year period for each lane mile of highway that is resurfaced under the special provision for rideability.

This synthesis will be of interest to state DOT construction, materials, statistical, specification, and inspection engineers; DOT research staff; pavement construction material suppliers; highway construction contractors; and civil engineering consulting firms, including field and laboratory materials testing personnel. The synthesis describes the state of the practice for defining and measuring variability in highway pavement construction. Data obtained from a review of the literature, a survey of state departments of transportation (DOTs), and discussions with selected state DOT personnel and private materials producers are presented. This report of the Transportation Research Board defines several measures of variability but concentrates on the use of standard deviation as the usual measure of variability. The synthesis updates reported typical variabilities found in materials and construction specifications. Also included are discussions of current research activities as related to variability, how variability can be used in the development of specification limits, the use of incentives and disincentives in specifications, and the need for additional information on the variability of several materials and construction processes.

TRB's National Cooperative Highway Research Program (NCHRP) Report 704: A Performance-Related Specification for Hot-Mixed Asphalt provides a proposed performance-related specification (PRS) for hot-mix asphalt (HMA) in the form of the Microsoft Windows-based Quality-Related Specification Software (QRSS). The QRSS is a stand-alone program for Microsoft Windows (versions XP and 7) that employs a database of pre-solved solutions of the Mechanistic-Empirical Pavement Design Guide. The program is capable of (1) calculating the predicted rutting, fatigue cracking, and low-temperature (thermal) cracking of an HMA pavement from the mix volumetric and binder and aggregate properties of the as-designed HMA (typically the job mix formula) and (2) comparing them with predictions calculated from the contractor's lot or sub-lot quality assurance data for the same properties.

This report from the second Strategic Highway Research Program (SHRP 2), which is administered by the Transportation Research Board of the National Academies, describes suggested performance specifications for different application areas and delivery methods that users may tailor to address rapid highway renewal project-specific goals and conditions.