STUDY OF TRAFFIC FLOW ON A RESTRICTED FACILITY. REPORT III-2. A METHODOLOGY TO MEASURE THE INFLUENCE OF TRUCKS ON THE FLOW OF TRAFFIC

As a means of describing the effect of trucks on the peak period traffic flow rate, the parameters of time headway and velocity were investigated. By analyzing and comparing time headways for vehicles, a factor, Truck Influence Ratio (TIR), was developed which expresses the number of passenger cars displaced by a truck. The factor was expanded to give an estimation of the percentage reduction in the flow rate due to the presence of trucks in the traffic lane. Analysis of the data collected showed that a truck displaces 1.5 passenger cars during periods of heavy traffic demand, that is, the TIR equals 1.5 passenger cars per truck. Therefore, the existence of trucks in the traffic stream results in a seven percent reduction in the flow rate.

  • Supplemental Notes:
    • Sponsored in part by Maryland State Highway Administration, Brooklandville. Bureau of Research. See also PB-282 512 and PB-282 514.
  • Corporate Authors:

    University of Maryland, College Park

    Transportation Studies Center, Department of Civil Engineering
    College Park, MD  USA  20742

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  USA  20590

    Maryland Department of Transportation

    Bureau of Research, 2323 West Joppa Road
    Brooklandville, MD  USA  21022
  • Authors:
    • Berman, W
    • Loutzenheiser, R C
  • Publication Date: 1976-10

Media Info

  • Pagination: 105 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00180867
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: FHWA-MD-R-77-7 Intrm Rpt., TSC-0019
  • Files: NTIS, TRIS, USDOT, STATEDOT
  • Created Date: Sep 14 1978 12:00AM