The development, application, accuracy, and reliability is described of an empirical method based on 135 sound level measurements taken at 120 locations near rural and urban freeways, highways and along residential streets. The construction and the statistical evaluation of the mathematical models that form the basis of the Ontario method are outlined. This model enables prediction of L50 and L10 sound levels with a higher level of accuracy than the Delany method. The standard error of estimate for L10 levels by the Ontario method was about 2.2 dBA. This indicated that 3 predictions out of 4 will be within plus or minus 2.5 dBA. The standard of error estimate for L50 was about 2.8 dBA. A procedure for application is briefly outlined. The design guide or the BBN method and the Delany method developed in England were evaluated and compared, and the statistical parameters are tabulated. The studies led to the conclusions the the Ontario method was the most accurate. It was also found that the sound levels emitted by trucks with gross vehicle weight of 10,000 or more pounds, increase with speed; the rate of attenuation with distance depends on percentile of sound level; and the sound levels calcualted by the Ontario method utilizing traffic volumes based on comprehensive traffic counts may be more representative than field measurements during a selected 15-min. period.

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 59-69
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00131401
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: May 14 1976 12:00AM