The streamlining of the NCHRP 117 model involved the consolidation of charts and tables, the development of a one-page worksheet and the development of tables for the commonly used parts of the charts thus eliminating the need for repeated visual interpolation. A change was made in the shielding chart of the manual predictions chart - a change that eliminated trial and error from the barrier design process. The 117 model has been programmed into a desk top Hewlett Packare calculator, one feature of which is the direct use of D sub e for computation of L sub 50. The use of the model to design a noise barrier is briefly described. Examples are outlined of the use of the model for designing an experiment noise barrier? use for measuring sound levels along a proposed route as a basis for assessing the environmental impact? and the assessment of noise impact on an urban arterial street. Aspects which have been shown by experience to require consideration are listed, and items which need to be researched, quantified and modeled are indicated. These items relate to low-volume traffic conditions, health benefits and noise abatement, the effect of barriers and roadway elements on noise statistics, shielding provided by various elements, the measuring of vehicle acoustical power, reflection and scattering of sound, the tire-pavement system, effect of winds, and the value of barriers.

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 48-59
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00131400
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: May 14 1976 12:00AM