NOISE CONTROL EARTH BERMS : GUIDELINES FOR THE USE OF EARTH BERMS TO CONTROL HIGHWAY NOISE

Since 1989, the Ministry of Transportation & Highways of British Columbia (MoTH) has had a noise impact mitigation policy which applies to all new or upgraded freeway and expressway projects. This policy is intended to prevent excessive noise impacts at residences and educational facilities and requires that mitigation measures be considered wherever project-related noise increases are predicted to exceed certain limits. Where such mitigation measures are warranted, cost-effective and widely supported by the directly affected community, they are to be carried out. Mitigation measures generally take the form of noise barriers constructed within MoTH right-of-way. Three basic configurations are employed: walls, earth berms or berm/wall combinations. The MoTH policy limits the height of walls to 3 m, but no such limit exists for earth berms or berm/walls. Given their natural appearance and potentially lower costs, earth berms have often been the preferred form of mitigation where space is available. Since the MoTH noise policy requires that mitigation measures achieve average noise reductions of 5 dBA or more, it is crucial that the relative noise reduction capabilities of the three forms of noise barriers be well understood. While experimental assessments to date have yielded mixed results, some highway noise prediction models assign a noise reduction bonus of 3 dBA to earth berms in recognition of their relatively broad and soft tops. To assess the validity of this "soft top correction" and to explore the effects of adding walls to the tops of earth berms, MoTH has funded research by the U.B.C. Mechanical Engineering Department (through the Professional Partnership Program) and Wakefield Accoustics Ltd. (A)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0772629641
• Corporate Authors:

  BRITISH COLUMBIA. MINISTRY OF TRANSPORTATION AND HIGHWAYS. HIGHWAY ENGINEERING BRANCH

  940 BLANSHARD STREET
  VICTORIA, BRITISH COLUMBIA  Canada  V8W 3E6
• Authors:
  • WAKEFIELD, C W
• Publication Date: 1997

Language

• English

Subject/Index Terms

• TRT Terms: Noise; Noise barriers; Specifications; Traffic
• ITRD Terms: 8018: Canada; 8525: Conference; 9009: Decrease; 2442: Emission; 9102: Method; 2492: Noise; 2886: Noise barrier; 177: Specifications; 755: Traffic; 1155: Transport; 313: Urban area
• Subject Areas: Environment; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00792916
• Record Type: Publication
• Source Agency: Transportation Association of Canada (TAC)
• ISBN: 0-7726-2964-1
• Files: ITRD
• Created Date: May 31 2000 12:00AM