Saturation Flow Rate,Start-Up Lost Time,and Capacity for Bicycles at Signalized Intersections

Abstract

A review of the literature shows that capacity and saturation flow rate for on-street bicycle lanes at intersections have not been measured on the basis of bicycle discharge at intersections at the start of the green phase. The Highway Capacity Manual 2000 recommends a saturation flow rate of 2,000 bicycles per hour for a bicycle lane at a signalized intersection. However, this recommendation is not based on field studies at the intersection and is not a function of the width of the bicycle lane. A revised estimate is provided of saturation flow rate, and an estimate is provided of start-up lost time for bicycles based on data collected at the stop line of signalized intersections. In addition, the lateral stopped distance of automobiles from bicycle lanes, the lateral stopped distance of bicycles from adjacent lanes, and the lateral and longitudinal stopped distance between pairs of bicycles at a signalized intersections are presented. Bicycles may form more than one queue within a bicycle lane at the stop line. Since bicycles maintain a certain distance from the adjacent lane and the curb, the number of queues formed varies based on the width of the bicycle lane. Therefore, the saturation flow rate for a bicycle lane depends on the number of queues or the width of the bicycle lane. The saturation flow rates for bicycle lanes of varying widths are proposed on the basis of the lateral stopped distance of bicycles. Empirical evidence from intersections in Colorado and California is used to propose a new method to estimate the capacity for a bicycle lane.

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References

Highway Capacity Manual. TRB, National Research Council, Washington, D.C., 2000.

Homburger

W. S.

Capacity of Bus Routes, and of Pedestrian and Bicycle Facilities. Institute of Transportation Studies, University of California, Berkeley, Feb. 1976.

Ferrara

T. C.

A Study of Two-Lane Intersections and Crossings Under Combined Motor Vehicle and Bicycle Demands. Civil Engineering Department, University of California, Davis, Dec. 1975.

Botma

, and Papendrecht

. Traffic Operation of Bicycle Traffic. In Transportation Research Record 1320, TRB, National Research Council, Washington, D.C., 1991, pp. 65–72.

Navin

F. P. D.

Bicycle Traffic Flow Characteristics: Experimental Results and Comparisons. ITE Journal, Vol. 64, No. 3, 1994, pp. 31–37.

Opiela

K. S.

, Khasnabis

, and Datta

T. K.

. Determination of the Characteristics of Bicycle Traffic at Urban Intersections. In Transportation Research Record 743, TRB, National Research Council, Washington, D.C., 1980, pp. 30–38.

Kroll

, and Ramey

M. R.

. Effects of Bike Lanes on Driver and Bicyclist Behavior. Journal of Transportation Engineering, ASCE, 1977, pp. 243–256.

Harkey

D. L.

, and Stewart

J. R.

. Evaluation of Shared-Use Facilities for Bicycles and Motor Vehicles. In Transportation Research Record 1578, TRB, National Research Council, Washington, D.C., 1997, pp. 111–118.

Raksuntorn

, and Khan

S. I.

. Speed of Bicycles at On-Street Bicycle Facilities. Journal of Transportation Engineering, ASCE (submitted).

10.

Wei

, Feng

, Meyer

, and Lee

. Video-Capture-Based Methodology for Extracting Multiple Vehicle Trajectories for Microscopic Simulation Modeling. Presented at the 78th Annual Meeting of the Transportation Research Board, Washington, D.C., 1999.

11.

Khan

S. I.

, and Raksuntorn

. Accuracy of Numerical Rectification of Video Images to Analyze Bicycle Traffic Scenes. In Transportation Research Record: Journal of the Transportation Research Board, No. 1773, TRB, National Research Council, Washington, D.C., 2001, pp. 32–38.