01157042

Component

This study investigated the lane flow distributions, defined as the proportion of each lane’s volume out of total volume at a given link, in 2-, 3-, and 4-lane basic segments of freeways under various traffic conditions including uncongested, transition and congested conditions. Unlike previous studies using traffic volume, this study proposed density measure to represent accurate lane flow distributions. In uncongested condition, lane flow ratio of median lane increased continuously and all flow ratios became close each other with increasing level of congestion. During transition to congested condition, lane flow ratio in the median lane increased continuously; while highest lane flow ratio in the middle and right-most lanes decreased with increasing density ratio of link from all three sites. In addition, the median lanes of 2-lane, 3-lane, and 4-lane may reached their capacities just before the link reached capacity, which leads the fact that median lane can provide very important information to examine the link congestion level. When the lane flow ratio is equal to 1.0 in median lane, density ratio tends to increase as the number of lane is increased from 2-lane to 4-lane sites. Estimated regression models fit fairly well to validation data except very low traffic condition. The two-sample Wilcoxon rank sum test showed that even two sites have similar geometric and traffic flow characteristics, there may exist potential factors influencing difference in lane flow distributions over sites such as trip purpose, driver population, origin/destination of trip, etc. The lane flow ratio was affected by truck volume but truck lane flow ratio was not much affected by truck volume. Truck lane flow ratios of individual lanes were significantly different each other. For all traffic range except midnight period, truck lane flow ratios appeared to maintain an equilibrium state when truck volume reached 10-20% of total traffic flow.

01147878

10-1947

English

25p

2010

Transportation Research Board 89th Annual Meeting

DVD

Figures; Maps; References (22) ; Tables (3)

Freeway operations; Merging traffic; Traffic congestion; Traffic flow; Traffic lanes; Traffic volume; Trip purpose; Truck traffic

Traffic conditions

Highways; Operations and Traffic Management; I73: Traffic Control

Transportation Research Board Annual Meeting 2010 Paper #10-1947

TRIS, TRB

Jan 25 2010 10:54AM