1976•Unpublished venueRequires access
STUDY OF TRAFFIC FLOW ON A RESTRICTED FACILITY. REPORT III-2. A METHODOLOGY TO MEASURE THE INFLUENCE OF TRUCKS ON THE FLOW OF TRAFFIC
W Berman, R C Loutzenheiser
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Abstract
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.