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The 2010 Highway Capacity Manual. Richard Dowling. The Highway Capacity Manual. 4 Editions & 1 Update from 1950 to 2000 HCM 2000 24,500 copies distributed (14% metric) Another 500 copies for the 2011 PE Exam Most fervent readers: Students and software developers
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The2010 Highway Capacity Manual Richard Dowling
The Highway Capacity Manual • 4 Editions & 1 Update from 1950 to 2000 • HCM 2000 • 24,500 copies distributed (14% metric) • Another 500 copies for the 2011 PE Exam • Most fervent readers: • Students and software developers • Everybody using traffic analysis software uses HCM
Major Changes for 2010 • Guidance on Integrating Microsimulation and HCM • Multimodal (Complete Streets) LOS Analysis • Software • Active Traffic Management • Partially Electronic Format • New HCM 2010 Support Website
Presentation Outline • Content, Format, Schedule, Software • Technical Innovations • Uninterrupted flow facilities (freeways, rural highways) • Interrupted flow facilities (urban streets, signals) • Alternative Methods (microsimulation) • Active Traffic Management
Format and Content - It won’t come entirely in printed form - One part will come entirely in electronic form - Software: source code available to all - A website for extra materials
Organization of Manual • Volume 1 – Concepts • Volume 2 – Uninterrupted Flow Facilities • Freeways, rural highways, rural roads • Volume 3 – Interrupted Flow Facilities • Urban arterials, intersections, roundabouts • Signals at freeway interchanges, • Bicycle and Pedestrian paths • Volume 4 – Supplemental Materials
Vol.1 – Concepts of Capacity • Target Audience: Managers, Students • Nine chapters that cover….. • Concepts • Traffic flow, capacity, quality of service • Modal characteristics • Capacity Analysis Applications • How to apply the HCM • How and when to use microsimulation • Interpretation and presentation of results
Vol. 2 – Uninterrupted Flow Facilities • Target Audience: technical people • Six chapters on: • Freeways and their component sections • Basic sections, ramp merge/diverge, weaving • Multi-lane rural highways • Two-lane rural roads
Vol. 3 Interrupted Flow Facilities • Target Audience: Technical and professional people • Eight chapters on: • Urban arterials • Signalized intersections • Unsignalized intersections • Roundabouts • Signals at freeway interchanges • Bike and pedestrian paths • Multimodal Level of Service
Vol. 4 – Supplemental Materials • Target Audience: Engineers and programmers • 12 chapters, all electronic, on the web • More detailed descriptions of methods • Worked example problems • Annotated software source code • Technical reference library • HCM Application Guide • New: Active Traffic Management
Software • Software • Source code available to all • Illustrates how to program the methods • Can be used to verify commercial software • Will not compete with commercial software • Will have very limited user interface • Will work only for simple and limited example problems
Publication Schedule • In TRB Production • Publication December 2010
Technical Innovations Uninterrupted Flow Facilities Interrupted Flow Facilities
Uninterrupted Flow Facilities Technical Innovations New speed-flow equations New freeway analysis software New weaving method Service volume tables
Freeway Speed-Flow Curves • Free-Flow Speed • No longer function of number of lanes • Ramp density substituted for interchange density • New curve for 75 mph free-flow speed • Speed does not drop until 1200 vph/ln reached
Weaving Sections • Changes to Current Method • New weaving section types • New method for estimating speed • Weaving length dependent on demands. • New method for estimating capacity
Freeway Facility Analysis • Modifications to reflect changes in other chapters • New software implementation (FREEVAL) • Updated capacity information for: • Work Zones • Weather (rain, snow, wind, visibility) • Incidents
Service Volume Tables • Rural Freeway ADT’s (1000’s)
Multi-lane Highways • Bicycle LOS analysis added • Service volume tables
Two Lane Highways • Two-way analysis methodology dropped. • Some revisions to curves and tables. • New road class added for built-up areas. • LOS based on % free-flow speed (FDOT) • Bicycle LOS on two-lane highways. • Service volume tables
Interrupted Flow Facilities Technical Innovations: New multimodal level of service method New methods for arterials and signals New method for signals in an interchange New method for roundabouts
Multimodal Level of Service • Simultaneous analysis of LOS for auto drivers, bus riders, bicyclists, pedestrians. • A method for allocating scarce street right-of-way to the various modal users of the street.
Sharing the Street – Complete Streets Before After
Urban Street Analysis • Predicts Stops (New), Speed, Queues • Models signal coordination • force offs, yields • Mixed street: signal, stops, roundabout • Sensitive to access management • driveways, median breaks • Service Volume Table
Signalized Intersection Updates • Incremental queue analysis (IQA) • Traffic actuated signals • Min. green, passage time, recall, dual entry, Dallas phasing, simultaneous gap out, detector length. • Left turn queue overflow check (New) • Volume/capacity ratio check (New) • Level of service for bicycles and pedestrians (New)
Incremental Queue Analysis Delay polygon for shared left-through lane with permitted lefts Old New Queued Vehicles Time
Left Turn Overflow Check (New) If left turn overflow occurs, review results
Volume/Capacity Ratio Check • if: v/c > 1.00 • Then the signalized intersection LOS is “F”
Two-Way Stop Updates • Extended to 6-lane arterials. • U-turns • Analysis of shared lanes, short lanes • Pedestrian crossings analysis
All Way Stop Updates • Queuing model added • Explicit guidance for 6-lane streets
Roundabouts Update • New methodology based on US Research • NCHRP Report 572 • U.S. Capacities lower than rest of world • LOS based on delay • Same thresholds as for unsignalized intersections • Roundabouts held to higher standard than signals
Roundabout Capacity Slide courtesy of: Lee Rodegerdts, Kittelson & Associates
Capacity: 1 lane Slide courtesy of: Lee Rodegerdts, Kittelson & Associates
Capacity: 2x1 lane Slide courtesy of: Lee Rodegerdts, Kittelson & Associates
Capacity: 1x2 lane Slide courtesy of: Lee Rodegerdts, Kittelson & Associates
Capacity: 2x2 lane Slide courtesy of: Lee Rodegerdts, Kittelson & Associates
Interchange Ramp Terminals • Analysis of Diamonds, Par-clos, Roundabouts • Methodology for choosing interchange types • Lost capacity due to: • Queue spillbacks • Uneven lane utilization • Demand starvation
Alternative Methods When and how to apply microsimulation. Comparing microsimulation results to HCM results
Chapter 6: HCM and Alternative Tools • Planning Methods Based on the HCM • Alternative Methods (Microsimulation) • Traffic modeling concepts • Application guide • Framework to apply HCM + microsimulation • Comparison of performance measures • Selection of traffic models
Chapter 7 Interpreting Results • Uncertainty and Variability • Concepts, Sources, Sensitivity Analysis • Uncertainty and Sensitivity of HCM results • Comparing HCM and Microsimulation Results • Framework for comparing HCM/microsim results • Specific guidance provided in facility specific chapters • Presentation of HCM/Microsimulation Results • Significant digits for reporting
Microsimulation vs HCM Delay Microsimulation Delay Accumulated Vehicles Arrivals HCM Delay Departures Queue Dissipation Time Time Analysis Period
Active Traffic Management New chapter on the continuous real time monitoring and management of both demand and capacity
Active Traffic Management • ATM is a comprehensive approach to optimizing the operational performance of the roadway system through monitoring and control of systems operations and demands. • Examples • Demand Metering, Congestion Pricing, Managed Lanes, Adaptive Control, Speed Harmonization, Traveler Information Systems, Incident Management, Work Zone Management
Active Traffic Management • Provides basic information on active traffic management measures • Provides references from the literature • Describes applicability of HCM or microsimulation methods to evaluation • New methodology coming in one year
Conclusion – The New HCM • New tools for multimodal planning • Guidance on the use of microsimulation • New methods for freeways and streets • Service volume tables for planning applications • New material to aid software programmers • Information on Active Traffic Management