Citation

Hall FL, Gunter MA. Transp. Res. Rec. 1986; 1091: 1-9.

Copyright

(Copyright © 1986, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

On the basis of Inspection of time-traced plots of daily flow and concentration data for a freeway, additional support is provided for some tentative new ways of looking at the rela- tionship between these variables. Occupancy data are used to directly measure concentration, rather than converting to den- sity. The overlaid, daily time traces help to make clear the nature of operations and of transitions between congested and uncongested regimes. Four principal conclusions are sup- ported by these plots. First, the underlying inverted V-shape for the flow-occupancy relationship found earlier at a single lane and station on the same freeway has been confirmed at several locations for both of the nonshoulder lanes. Second, for the shoulder lane, it is not possible to determine from these data whether the Inverted V-shape correctly describes the relationship. Third, definite differences exist in the parameters of the flow-occupancy relationship that appear to be attributa- ble to lane and location. Fourth, there is additional support for the finding reported In an earlier paper of the authors (Trans- portation Research, Vol. 20A, 1986) that discontinuous relation- ships are not necessary to describe the data obtained from freeway operations. Better sense may be made by assuming continuous relationships and trying to explain sparseness of data by the nature of operations on the faclllty.

Language: en

Keywords

TRAFFIC SURVEYS; HIGHWAY TRAFFIC CONTROL; HIGHWAY SYSTEMS - Speed Control