This analysis concludes that the use of rubberized asphalt on Alta Arden Expressway and Antelope Road resulted in a net decrease in traffic noise levels of approximately 4 dB over that provided by conventional asphalt. These conclusions hold for both the near and long-term conditions. The noise reduction provided by the rubberized paving was achieved predominately in the 500 to 4,000 Hertz frequency bands, which is consistent with the frequency character of tire noise.

These local test results, when considered with other studies conducted nationally and internationally, support the use of rubberized asphalt as a viable noise mitigation option. Its use could, in some cases, eliminate the need for noise barriers or reduce the heights of the barriers required to achieve satisfaction with local, state and federal noise standards.

It should be noted that the effectiveness of rubberized asphalt in reducing traffic noise levels would be highest on roadways with relatively low percentages of heavy duty trucks, as truck engine and exhaust stack noise is not believed to be substantially affected by rubberized paving.

Table of Contents | Executive Summary | Introduction | History of Noise Reducing Pavement | The Process of Producing Rubberized Asphalt | Current Uses of Rubberized Asphalt | Tables | Studies of Rubberized Asphalt Outside of Sacramento County | Sacramento County Rubberized Asphalt Noise Studies | Conclusions of the Studies Conducted in Sacramento County | Appendix A - Acoustical Terminology | Appendix B - Noise Standards Commonly Applied to Projects in Sacramento County