@article {Sandberg:2020:0736-2935:4863,
title = "Evaluation of Noise Reduction of Korean Low-Noise Pavements - Part 2: Issues regarding the application of the CPX method",
journal = "INTER-NOISE and NOISE-CON Congress and Conference Proceedings",
parent_itemid = "infobike://ince/incecp",
publishercode ="ince",
year = "2020",
volume = "261",
number = "2",
publication date ="2020-10-12T00:00:00",
pages = "4863-4874",
itemtype = "ARTICLE",
issn = "0736-2935",
url = "https://ince.publisher.ingentaconnect.com/content/ince/incecp/2020/00000261/00000002/art00094",
author = "Sandberg, Ulf and Kim, Hyunjin",
abstract = "In another paper at this conference, the noise reduction of a couple of double-layer porous asphalt pavements compared to a couple of dense pavements is reported. They used a special roadside LAeq-measuring method and the CPX method (ISO 11819-2). Noise reduction was then found to be
up to 14 dB(A) compared to tined cement concrete; a result hard to believe for noise and pavement experts. The study also seemed to indicate that the noise reducing effect measured as roadside equivalent level is most similar to the measurement results of the optional rear microphone location
in the CPX method, rather than to the mandatory side microphone location. Those observations have raised questions about the reason for such results. This paper attempts to identify the reasons by analyzing the geometries of the road surroundings vs microphone positions and discuss the effects
of multiple reflections over absorbing vs not absorbing pavements. It also looks at the differences in noise reduction obtained when comparing results measured as LAmax vs LAeq. Further, the different features of the side vs the rear microphones in the CPX method are discussed. The paper ends
with presenting the possible reasons for the results and suggests some recommendations.",
}