Citation

Long G, Gan CT. Transp. Res. Rec. 1997; 1579: 53-62.

Copyright

(Copyright © 1997, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

10.3141/1579-07

PMID

unavailable

Abstract

A signalized intersection typically operates under both saturated and undersaturated traffic flow conditions at different times of the day. When an intersection operates under saturated flow conditions, its ability to dissipate traffic becomes a primary matter of concern. On the other hand, safety is often the major concern due to higher vehicular travel speeds associated with undersaturated flow conditions. The minimum corner clearance distances required under the two different flow conditions are not the same. To be effective, minimum corner clearances must be set such that the needs under both types of flow conditions are satisfied. Existing guidelines for minimum corner clearances were reviewed, and none were found to address the capacity issue. A new model designed to meet both capacity and safety needs is proposed. The model produces a refined minimum corner clearance distance by applying a set of adjustment factors to an initial minimum corner clearance, a procedure similar to that of the familiar Highway Capacity Manual for adjusting the ideal saturation flow rate. Unlike existing guidelines, the proposed model is flexible, is much less discrete for continuous variables, and can easily incorporate as many factors affecting corner clearance as needed.

Language: en