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Porous Elastic Road Surface as Urban Highway Noise Measure

Highway traffic noise is a serious problem in urban areas of Japan, not only for residents along highways but also for highway administrators. Only 13% of urban highways have met the environmental standard for noise. Noise barriers cannot be used as a noise countermeasure on most highways for which access is not controlled. This problem is impeding new highway construction in urban areas. Since 1993 the Public Works Research Institute (PWRI) has been developing a new low-noise pavement called porous elastic road surface (PERS). This new pavement has a porous structure composed of granulate rubber made from used tires as its aggregate and urethane resin as its binder. It is estimated that the potential noise reduction levels in the Leq sound level exceed 10 dB (A). More than 90% of highways in urban areas would meet the standard if this noise reduction level were achieved. The general performance of PERS obtained through past development at the PWRI is examined. Results of recent research done to improve the noise reduction levels of PERS further and the first test construction using PERS in Japan are summarized. The noise measurement result at the site indicates that PERS has enough potential to solve highway traffic noise problems in urban areas of Japan.