Citation

Weinert A. Transp. Res. Circular 2000; (E-C018): 409-421.

Copyright

(Copyright © 2000, U.S. National Academy of Sciences Transportation Research Board)

DOI

unavailable

PMID

unavailable

Abstract

New critical gaps and follow-up times were investigated to prepare the improved guideline for unsignalized intersections in Germany. These guidelines will form part of the future "Handbuch zur Bemessung von Strassenverkehrsanlagen" (HBS), the German equivalent of the U.S. "Highway Capacity Manual" (HCM). The studies were based on empirical data collected at unsignalized intersections all over the German territory. Follow-up times were measured directly by observing traffic flow at these intersections; however, the critical gaps could only be derived by measuring those gaps accepted and rejected by drivers. The "maximum likelihood technique" was applied for this purpose. Resulting critical gaps and follow-up times were analyzed to determine their dependence on parameters such as intersection layout, speeds, and volumes. These parameters were tested using the conventional calculation method for intersections without traffic signals. The parameters were then integrated into the capacity estimation diagrams for the new German HBS so that capacity and traffic flow can be determined reliably and appropriately for actual situations.