UBC Theses and Dissertations
An evaluation of noise barriers designed for truck traffic Jenkins, Robert Andrew
Recently attention has been directed towards noise resulting from traffic on arterials, especially those arterials carrying high volumes of truck traffic. This thesis addresses the question, "Are there traffic noise barrier designs which reduce noise effectively when employed on arterials carrying high volumes of truck traffic?". Criteria for evaluating barriers are derived from existing research and are the following: 1) Noise attenuation effectiveness. 2) Aesthetic impact. 3) Circulation effectiveness (pedestrian and vehicular). 4) Cost. Noise attenuation effectiveness is dealt with more extensively than the other criteria. A noise prediction method is selected from three methods used in recent traffic noise research. The criteria for selection of the Ontario Noise Prediction Method are based on its comparative: 1) Accuracy; 2) Comprehensiveness (capability to deal with diverse traffic situations such as low traffic volumes, truck traffic and barrier configurations); 3) Simplicity of application. Target noise level standards are developed considering both ambient noise levels and speech interference criteria. Five design archetypes based on existing research are introduced. These designs involve lowered roadbeds, berms (earth mounds), and combinations of these structures. The archetypes are evaluated with respect to a case study situation involving the potential conflict between truck traffic from the Coquitlam River area and the proposed Coquitlam Town Centre located in the Lower Fraser Valley Region of British Columbia. Important in the case study is consideration of future truck and auto volumes which will generate the noise and consideration of the land use types bordering the route. Different target noise levels are suggested for different land use types. Each of the archetypes plus a control situation (no noise barrier) are evaluated with respect to the criteria of noise attenuation effectiveness, aesthetic impact, circulation effectiveness and cost. Conclusions and recommendations result regarding the effectiveness of the archetypes. Employing the Ontario Noise Prediction Method appears to be a successful means of evaluating barrier noise attenuation effectiveness. All barrier designs are considerably more desirable with respect to target noise levels than the control situation. However, desirable reductions in noise are only realized at elevations lower than 40 feet above ground as noise shadows created by the barrier configurations do not extend above this height. The designs which are most expensive from a construction standpoint entail the widest right of way width. If the purchase of land is considered in a total cost the extra land costs could override the cheaper construction costs. The designs are comparable from a circulation standpoint but the berm designs emerge as more aesthetically effective. Employing the methodology suggested in the thesis (and outlined here) constitutes an effective means of evaluating traffic noise barriers.