01366488

Component

https://doi.org/10.3141/2286-03

http://scholar.google.com...vers&publication_year=2012

Auxiliary through lanes (ATLs) are often implemented at congested signalized intersections where fiscal and right-of-way constraints do not allow for full roadway widening. Previous research has suggested that ATLs are used significantly less than the theoretical capacity of a continuous lane. However, analysts have had little empirical basis for evaluating ATL operations in the context of the 2010 Highway Capacity Manual (HCM). Two empirical models that predict the flow in the ATL as a function of congestion and total through-movement flow are presented. A method is described for incorporating the model’s findings into the HCM procedure for estimating approach capacity. The study addresses the challenges of modifying the HCM lane utilization factor and accounting for the iterative effect of actuated signal control on ATL use. The study suggests that a cyclic process can be used to balance the ATL flow with the green-to-cycle-length ratio. A method is presented for determining the upstream ATL length needed for efficient ATL operations. Two example problems illustrate the use of the new models in the context of HCM 2010.

01450371

12-0231

English

pp 21–28

2012

Transportation Research Record: Journal of the Transportation Research Board

9780309223263

Print

Figures; References; Tables

Auxiliary lanes; Highway capacity; Highway operations; Length; Traffic actuated controllers; Traffic congestion; Traffic flow; Traffic models

Highway Capacity Manual 2010

Highways; Operations and Traffic Management; I73: Traffic Control

TRIS, TRB, ATRI

Feb 8 2012 4:53PM

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• Operational Performance and Speed–Flow Relationships for Basic Managed Lane Segments
• Rationale for Incorporating Queue Discharge Flow into Highway Capacity Manual Procedure for Analysis of Freeway Facilities