Abstract
The present paper focuses on capacity of tunnels and sags on motorways. Free flow becomes congested due to speed reduction caused by sudden change of light condition at tunnel entrances or by unrecognized increase of gradient at sags combined with drivers’ behavior that they do not shorten their car-following spacing corresponding to the speed reduction, resulting in reduction of flow rate of successive vehicles. The free flow to congested flow breakdown takes place at the flow rate level of around 3,000 vph per two-lane (one direction). Once congestion queue is formed, the capacity value is determined by drivers’ behavior of departing from the queue at its front-end. This departure flow rate is in the range of 2,200 to 2,700 vph per 2-lane and varies depending on time during which the driver has been caught in the queue, light condition (day or night) and some other factors.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
M. Koshi, Traffic Phenomena in Expressway Tunnels, IATSS Review, International Association of Traffic and Safety Sciences, Vol. 10, No. 1, 1984. 3.
M. Koshi et. al., A Study of the Phenomena of Congested Traffic Flows, Journal of Infrastructure Planning and Management, Japan Society of Civil Engineers, No. 306, pp. 59–69, 1981. 2.
M. Koshi et. al., A Study on Congestion Phenomena at Tunnels and Sags on Motorways, Journal of Infrastructure Planning and Management, Japan Society of Civil Engineers, No. 458/IV-18, pp. 65–71, 1993. 1.
J. Xing and M. Koshi, A Study on the Bottleneck Phenomena and Car-Following Behavior on Sags of Motorways, Journal of Infrastructure Planning and Management, Japan Society of Civil Engineers, No. 506/IV-26, pp. 45–55, 1995. 1.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2003 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Koshi, M. (2003). An Interpretation of a Traffic Engineer on Vehicular Traffic Flow. In: Fukui, M., Sugiyama, Y., Schreckenberg, M., Wolf, D.E. (eds) Traffic and Granular Flow’01. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-10583-2_18
Download citation
DOI: https://doi.org/10.1007/978-3-662-10583-2_18
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-07304-5
Online ISBN: 978-3-662-10583-2
eBook Packages: Springer Book Archive