Citation

Ringert J, Urbanik TII. Transp. Res. Rec. 1993; 1398: 31-41.

Copyright

(Copyright © 1993, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Observations of flow rates much higher than 2,000 passenger cars per hour per lane and the recent revision of the multilane highway chapter in the Highway Capacity Manual have led to questioning the current value of freeway capacity and the speed-flow relationship. An analysis of free-flow and queue discharge flow rates at three freeway bottlenecks in Texas found less variability in queue discharge flow rates than in free-flow flow rates. Average free-flow flow rates ranged from 2,096 to 2,210 vehicles per hour per lane (vphpl) across all lanes, whereas queue discharge flow rates averaged approximately 2,175 vphpl for the study sites. In addition, higher flows did not occur in free-flow conditions in all cases. As a result of lane interaction, some lanes are prematurely transitioned into queue discharge without reaching high flow rates in free-flow conditions.

Record URL:
http://onlinepubs.trb.org/Onlinepubs/trr/1993/1398/1398-005.pdf

Language: en

Keywords

Traffic control; Motor transportation; Traffic surveys