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.
- Sponsored in part by Maryland State Highway Administration, Brooklandville. Bureau of Research. See also PB-282 512 and PB-282 514.
University of Maryland, College ParkTransportation Studies Center, Department of Civil Engineering
College Park, MD USA 20742
Washington, DC USA 20590
Brooklandville, MD USA 21022
- Berman, W
- Loutzenheiser, R C
- Publication Date: 1976-10
- Pagination: 105 p.
- TRT Terms: Dislocation (Geology); Flow; Freeways; Highway capacity; Highway traffic; Markov processes; Passenger car equivalence; Passenger vehicles; Peak hour traffic; Time; Traffic control; Traffic engineering; Traffic flow; Traffic surveys; Trucks; Tunnels; Vehicular tunnels; Velocity
- Uncontrolled Terms: Flow rate
- Geographic Terms: Maryland
- Old TRIS Terms: Truck effect on highway capacity; Vehicular traffic
- Subject Areas: Bridges and other structures; Highways; Motor Carriers; Operations and Traffic Management;
- 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