Citation

Easa SM. Transp. Res. Rec. 1982; 869: 25-36.

Copyright

(Copyright © 1982, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

A procedure for selecting two-regime macroscopic models for a given set of traffic-flow data is presented. The procedure is based principally on the theoretical characteristics among the various regions of macroscopic models, which includes the limiting case and the convexity and concavity properties. The input to the procedure is represented by the basic traffic-flow criteria (free-flow speed, optimum speed, jam density, and so on) as well as auxiliary criteria to account for the variability of the traffic-flow relations in the intermediate ranges of flow. With these criteria, which are established from the data, the procedure can directly output model parameters, through simplified graphical tools, for the non-congested and congested-flow regimes. Application of the procedure by using actual data was made to illustrate its use and to discuss some issues related to establishing the traffic-flow criteria from the data. This application also illustrates the flexibility of the procedure and the ease with which the specified criteria can be adjusted to further improve the data fitting. The procedure presented in this paper significantly reduces the need for using computer facilities in estimating traffic-flow relations and as such should prove useful in many transportation applications.

Language: en

Keywords

MATHEMATICAL MODELS; TRAFFIC SURVEYS