Citation

Ryan DP. Highw. Res. Board bull. 1962; 352: 100-114.

Copyright

(Copyright © 1962, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

A newly proposed concept for determining capacity, and capacity determinations for channelized left turn intersections are presented. Three types of capacity have been known to be utilized: Basic, practical, and possible. Using capacity per se the degree of capacity is specified on a percentage basis. From this last thought a new method of capacity determination was conceived and a preliminary analysis made. The method used an ogive curve with ordinate values of percent volume and abscissa values of percent maximum volume. A second abscissa scale was superimposed on the graph representing capacity as a percent of total capacity. The capacity study involved the analysis of 20 intersection approaches. The results obtained from the ogive curve were compared to capacities as determined by the average starting headway and the highway capacity manual methods. The results indicated that there may be some relationship between an ogive curve and capacity. On this basis the channelized intersection complexes were studied and capacities determined. The results indicate that intersections with the channelized left turn (new jersey left turn) are significantly more efficient than regular intersections.