HD13 - The Virginia Quiet Pavement Implementation Program Under Section 33.2-276 of the Code of Virginia - Final Report - June 2015


Executive Summary:
Introduction

Section 33.2-276 of the Code of Virginia directs the Virginia Department of Transportation (VDOT) to expedite the development of quiet pavement technology such that applicable contract solicitations for paving shall include specifications for quiet pavement and other sound mitigation alternatives in any case in which sound mitigation is a consideration. The statute requires VDOT to construct demonstration projects sufficient in number and scope to assess applicable technologies. The assessment shall include evaluation of functionality and public safety of these technologies in Virginia’s climate. Finally, § 33.2-276 requires VDOT to provide an initial interim report to the Governor and the General Assembly by June 30, 2012, a second interim report by June 30, 2013, and a final report by June 30, 2015 and provides that the report shall include results of demonstration projects in Virginia, results of the use of quiet pavement in other states, a plan for routine implementation of quiet pavement, and any safety, cost, or performance issues that have been identified by the demonstration projects.

It is noted that the original 2013 deadline for a final report was extended for 2 years, primarily to allow for two additional winters of experience with the demonstration projects. The extension also allowed for completion of an accelerated trafficking experiment with two of the technologies, as well as additional time for federal authorities to consider the viability of quiet pavement as a noise mitigation measure.

Purpose and Scope

The purpose of this study was to comply with the direction provided by Chapter 790 of the 2011 Virginia Acts of Assembly (Code of Virginia § 33.1-223.2:21, recodified as § 33.2-276). This statute directs VDOT to construct demonstration projects that incorporated quiet pavement technologies, assess their ability to reduce transportation noise, and evaluate the functionality and public safety ramifications of these technologies in Virginia’s climate. This document is the final in a series of reports that chronicled the selection of the lower-noise pavement technologies; the development and construction of demonstration projects; and the evaluation tools and analysis used to compare the performance of the alternative strategies. This report summarizes overall condition, functional performance (ride, noise, friction), winter maintenance and use characteristics, and other observations after as much as four winters under traffic. The report also summarizes results from accelerated trafficking of Virginia quiet pavement materials at the National Center for Asphalt Technology (NCAT) Test Track from fall 2012 to late fall 2014. Finally, the report reviews current federal policy on noise mitigation strategies, highlights relevant findings from important recent research, provides a status of national and international activities, and offers conclusions and recommendations as to Virginia’s way forward with respect to implementation of lower-noise pavement.

Methods

Much of the approach adopted to meet the objectives of this research was developed with the guidance of the Quiet Pavement Task Force (QPTF), an expert working group consisting of members from VDOT’s Materials, Maintenance, and Environmental Divisions; the Virginia Center for Transportation and Research (VCTIR); the Virginia Asphalt Association (VAA); the American Concrete Paving Association (ACPA); the Virginia asphalt contracting industry; and the Virginia General Assembly. The QPTF worked with researchers to select the lower-noise materials and treatments to demonstrate. The Task Force also established key requirements of the demonstration projects, helped identify locations, and worked with VDOT districts and contractors to install the projects. The QPTF was also instrumental in the accelerated trafficking experiment at NCAT.

Functional evaluation focused on tire-pavement noise, but also included early community wayside noise testing. Secondary testing to assess safety and comfort characteristics included tire-pavement friction and high-speed profiling (for ride quality). Winter maintenance experience was elicited from VDOT and contractor maintenance superintendents with direct responsibility for the demonstration projects.

Findings and Discussion

As of spring 2015, the difference in measured tire-pavement noise between the control surfaces and the most successful (lowest noise) quiet asphalt technology was no longer detectable with normal human hearing (<3 dB). The lowest noise concrete surface continues to have a noticeable (approximately 4dB) advantage over the standard concrete finish. All of the surfaces continue to have good resistance to skidding and excellent ride quality. The quiet asphalt surfaces also continue to provide good splash-spray characteristics with better wet-weather visibility. Unfortunately, the openness or porosity that enables the lower noise and better wet-weather performance of these asphalt surfaces also make them quicker to cool and more difficult to clear of frozen precipitation. Freezing precipitation contributed to vehicles “sliding into the ditches” along one demonstration project (Route 7 Leesburg) in early 2014 and led to “multiple accidents” and a brief facility closure on another (Fairfax County Parkway) in March 2015 . Local maintenance crews also report the need to apply deicing treatments earlier and more often on all of the quiet asphalt projects.

Pursuant to federal regulation (23 CFR, Part 772) the Commonwealth Transportation Board adopted Virginia’s State Noise Abatement Policy (SNAP) and pursuant to that policy, all transportation improvement projects developed in conformance with the Virginia Department of Transportation’s guidelines must be in conformance with those federal highway traffic noise impact analysis and abatement procedures and guidance mandated by FHWA. The federal regulations require that at least fifty percent of the impacted receptors receive a 5 dB(A) or more reduction in noise through the abatement strategy. VDOT must also achieve and maintain a design goal (for reasonableness) of 7 dB(A) of reduction for at least one impacted receptor. Based on the results of testing and demonstration projects conducted in response to § 33.2-276, QP technologies have not demonstrated the level of noise abatement required by federal regulations nor by VDOT guidelines developed in accord with the SNAP and federal regulations.

Federal regulations [23 CFR 772.15 (c)] also identify the abatement measures that are eligible for federal funding and QP technologies are not currently listed as eligible measures (19). Federal policy described in FHWA guidance memoranda ( http://www.fhwa.dot.gov/environment/noise/regulations_and_guidance/) specifically precludes the use of pavement type or surface texture as a noise abatement measure. It further states that provisional policy changes would require research that demonstrated the safety, durability, and noise-reducing capacity of each ‘quiet pavement,’ and these characteristics would need to be maintained in perpetuity.

Conclusions and Recommendations

All of the QP technologies examined through this research offer functional advantages over more conventional materials and finishes. They are initially quieter, have excellent resistance to skidding, and exhibit superior ride quality. The quiet asphalt (PFC) materials also provide beneficial spray reduction and improved wet-weather visibility. However, PFCs require close monitoring and aggressive application of deicing chemicals to avoid specific safety hazards during winter weather events.

None of the QP technologies provided sufficient noise reduction to singularly satisfy federal regulations for noise abatement, nor do federal regulations and policy currently recognize QP technology as an appropriate noise abatement measure. Furthermore, the noise reducing capability of the Virginia QP materials diminish with time. Over the course of this study, there has been a slight increase in the tire-pavement noise of the quiet concrete surfaces and a substantial increase in the tire-pavement noise for the quiet asphalt materials.

VDOT is nonetheless encouraged to continue monitoring federal policy for changes that may incorporate pavement type as a tool for mitigating noise. VDOT should also continue to monitor (and trial as warranted) products of national and international research and development that show promise for reducing and/or eliminating the need for traditional sound barriers.