Citation

Smith SA, Carter EC. Transp. Res. Rec. 1975; 533: 22-33.

Copyright

(Copyright © 1975, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Previous research has indicated that limiting traffic demand in an underwater vehicular tunnel can produce substantial increases in flow rates and speeds. A pretimed control system consisting of a standard traffic signal was used to meter traffic entering the Baltimore Harbor Tunnel. Four different cycle lengths and splits were tested, and the results were compared to those obtained from the uncontrolled situation. The increase in flow rates and speeds of 3 of the control strategies over those in normal operation showed that even a simple control system is capable of significantly benefiting traffic flow through a tunnel. An evaluation methodology was applied to the control alternatives; both quality of flow and flow rates were considered. Primary emphasis was placed on a methodology requiring a maximum of time and effort in data collection. The operations of the tunnel was observed in its 2 basic states--congested and uncongested. The quality of flow in a tunnel is poorest on the downgrade, better on the level section, and best on the upgrade. The results of this research should help to make pretimed, tunnel-bottleneck control a more practical engineering tool.