the Box-Behnken design and response surface method were applied to optimize the parameters of noise barriers. The height, length and initial stake of noise barrier were studied as arguments, while the insertion loss of three sound-sensitive points, construction cost as variables. Quadratic equation models were developed to express the functional relationship between arguments and variables. Optimization parameters of noise barrier were obtained by Minitab analysis, basing on the goals of acoustic environmental standard in sensitive area, as well as minimization of construction cost.

Based on investigation of built highway noise barriers in Jiangsu province, the effect of several factors, including equivalent frequency, traffic flow, etc, on insertion loss of highway noise barriers were analyzed, and the revision was carried out. The results show that the sound source model reflecting characteristic of traffic noise is the key to assess acoustic performance of noise barrier. Meanwhile, there were some construction defects on a few of noise barriers, leading to sound leakage and poor acoustic performance.