The thrust of the report report is the provision of guidelines for data collection techniques in evaluating traffic engineering improvements. Without uniformity in basic before-and-after data collection, an accurate evaluation of an improvement cannot be made, nor can estimates of financial and practical value be made. Accident reduction and savings in travel time are generally considered to be products of traffic improvement, but there is no standard method for measuring these improvements. The article describes the steps involved in proper data collection procedures. Condition diagrams present the physical layout of the location to be improved. Traffic volume counts, taken either manually or automatically, should be carried out twice both before and after, and should take into consideration vehicle classification or other special counts. Speed and delay studies are an essential feature of evaluation since they are an indication of the extent to which travel conditions have been improved. Spot speed studies may be taken at specified locations, or studies on longer routes are conducted by test cars. The equipment required for speed studies is unsophisticated, so the cost is minimal. The acquisition of accident data is integral in reducing the frequency of accidents. The time period used in collection of before-and-after data is very important, as well as use of standard accident forms and summaries, and development of accident costs. In recent years, photographic techniques have been added to the Considerations, and Analysis Techniques of data collection. more reliable information. Descriptions are given of three techniques; photologging, time-lapse closed circuit TV, and time-lapse photography. Part II of this report will furnish information on Socioeconomic Considerations, Environmental Considerations, and Analysis Techniques of data Collection.

  • Corporate Authors:

    Institute of Traffic Engineers

    2029 K Street, NW
    Washington, DC    20006
  • Publication Date: 1975-5

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 32-40
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00098545
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 13 1975 12:00AM