01366430

Component

https://doi.org/10.3141/2286-09

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

The freeway facilities methodology in the 2010 Highway Capacity Manual (HCM) is the only HCM methodology that encompasses undersaturated and congested flow regimes over multiple periods. However, the methodology is limited by its assumption of a fixed capacity threshold between the two flow regimes. The method does not consider the two-capacity phenomenon, which suggests that a drop in the throughput from theoretical capacity is observed after breakdown has occurred. A summary of the available literature on empirical evidence of the capacity drop under queue discharge conditions offers a theoretical evaluation of the impact on queue discharge flow based on shock wave theory relationships that form the basis of the queuing model used in the HCM freeway facilities method. Examples illustrate incorporating queue discharge into a freeway facilities analysis, and implications for practice are discussed.

01450371

12-1671

English

pp 76–83

2012

Transportation Research Record: Journal of the Transportation Research Board

9780309223263

Print

Figures; References; Tables

Freeways; Highway capacity; Traffic flow; Traffic queuing

Highway Capacity Manual 2010

Queue discharge flows; Shock wave theory; Throughput (Traffic)

Highways; Operations and Traffic Management; I71: Traffic Theory; I73: Traffic Control

TRIS, TRB, ATRI

Feb 8 2012 5:04PM

• Calibration and Validation of Highway Capacity Manual 2010 Capacity Model for Single-Lane Roundabouts
• Deterministic Approach to Managed Lane Analysis on Freeways in Context of Highway Capacity Manual
• Effect of Inclement Weather on Two Capacity Flows at Recurring Freeway Bottlenecks
• Ensemble Tree Approach to Estimating Work Zone Capacity
• Equilibrium of Probabilities for Estimating Distribution Function of Critical Gaps at Unsignalized Intersections
• Estimating Right-Turn-on-Red Capacity for Dual Right-Turn Lanes at Signalized Intersections
• Estimation of Capacity Drop in Highway Merging Sections
• Evaluating the Effects of Signal Countdown Timers on Queue Discharge Characteristics at Signalized Intersections in China
• Evaluating the Operational Impact of Left-Turn Waiting Areas at Signalized Intersections in China
• Field Data for Evaluating 2010 Highway Capacity Manual Operational Analysis Methodology for Interchange Ramp Terminals
• Implementing Auxiliary Through Lanes in Context of Highway Capacity Analysis
• Models for Estimating Drivers Following on Two-Lane Rural Highways
• Operational Performance and Speed–Flow Relationships for Basic Managed Lane Segments