Noise Barriers are widely installed to control the propagation of vehicle noise from highway. However, the installation may result in a secondary noise caused by reflection, especially, if there exists a residential area on the opposite side. Hence, to effectively use noise barrier, it is mandatory to first predict the noise sources taking place on the roadsides and to apply the findings afterwards. In this study, by evaluating the reduction effects of reflection noise according to different panel shapes including wing, zigzag and curved type, the optimal soundproof panel shape and design factor that can minimize the reflection noise are suggested. The sound reduction was modeled by general linear model for the case of zigzag and curved shape with nominal variances. Read more..