Scientific Research and Essays Vol. 7(50), pp. 4213-4229, 24 December, 2012 Available online at http://www.academicjournals.org/SRE DOI: 10.5897/SRE10.1134 ISSN 1992-2248 ©2012 Academic Journals Full Length Research Paper A case study on acoustic performance and construction costs of noise barriers Turgut Öztürk 1 , Zübeyde ÖZTÜRK 2 * and Metehan ÇALI 3 1 Structural Engineering Division, Faculty of Civil Engineering, İstanbul Technical University, 34469, Maslak, Sarıyer, İstanbul, Turkey. 2 Department of Civil Engineering, Faculty of Civil Engineering, İstanbul Technical University, 34469, Maslak, Sarıyer, İstanbul, Turkey. 3 Turkish Standards Institution, Construction Materials Laboratory, Gebze, Kocaeli, Turkey. Accepted 3 September, 2012 In the study, the barriers used for reducing traffic noise are being examined in means of performance and construction cost. First a noise prediction is made in the sample highway under certain traffic conditions in order to determine the noise barrier requirement and the results are confirmed by measurement. According to the noise prediction equations used in Turkey, Germany and Canada, the effects of heavy vehicle ratio, average traffic flow speed and hourly total vehicle quantity change on noise level and barrier requirement are examined, so assessment can be made for highways having different traffic specifications than the sample highway. In the continuation of the study, the working principle of noise barriers and effects of barrier position and height on reducing noise are researched in order to determine the construction costs of barriers in Turkey and Canada at different heights and made from different materials. Key words: Highway, noise barrier, noise prediction, performance, construction cost. INTRODUCTION Sound is a physical phenomenon that is caused by air pressure waves, emanated from a vibrating source, and alerts the hearing sense of human beings. While sound is an energy type that emits waves, noise is simply an unwanted sound. The magnitude of the highway traffic noise being analyzed in this study is drastically affected by the engine type of the vehicle, friction, velocity, road properties, and traffic volume. Discrete sources, caused by vehicles in a flowing traffic, turn into a linear source, which is the most stable source of all known random noise sources in the city, and causes a discomforting feeling at high levels (Beranek, 1971). Mitigation strategies are needed to be developed to eliminate the discomfort and bring down the noise level to proper *Corresponding author. E-mail: zozturk@itu.edu.tr. Tel: (+90212) 285 36 67 or 05327051011. values. People exposed to high traffic noise increases day by day. In Europe, the number of people exposed to noise levels leading to serious annoyance, speech interference and sleep disturbance is about 450 million (EEA, 2003). To protect people from hazard of traffic noise high levels, there are regulations and threshold values to control the noise even though they vary from country to country. The legislation in Turkey that concerns noise control is the 'Evaluation and Management of Environmental Noise Regulation’ issued by the Ministry of Environment and Forestry on 1 st of July, 2005. The objective of this regulation is “to create an environment that will not threaten the peace and tranquility, and physical and mental health of the public by unwanted noise” as defined in the regulation. According to this regulation, environmental traffic noise levels, L day and L night , should not exceed the threshold values given in Table 1 (Turkish Republic Regulation of