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Nagui M. Rouphail - One of the best experts on this subject based on the ideXlab platform.
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Incorporating Travel Time Reliability into the Highway Capacity Manual - Incorporating travel time reliability into the Highway Capacity Manual.
2014Co-Authors: John D Zegeer, Paul Ryus, Mark Vandehey, Richard G Dowling, James A Bonneson, Wayne Kittelson, Nagui M. Rouphail, Bastian J Schroeder, Ali Hajbabaie, Behzad AghdashiAbstract:This publication presents a summary of the work conducted during the development of two proposed new chapters for the Highway Capacity Manual 2010 (HCM2010). These chapters demonstrated how to apply travel time reliability methods to the analysis of freeways and urban streets. The two proposed HCM chapters, numbers 36 and 37, introduce the concept of travel time reliability and offer new analytic methods. The prospective Chapter 36 for HCM2010 concerns freeway facilities and urban streets, and the prospective supplemental Chapter 37 elaborates on the methodologies and provides an example calculation. The chapters are proposed; they have not yet been accepted by the Transportation Research Board's Highway Capacity and Quality of Service (HCQS) Committee. The HCQS Committee has responsibility for approving the content of HCM2010. The second Strategic Highway Research Program (SHRP 2) Reliability Project L08 has also released the FREEVAL and STREETVAL computational engines. The FREEVAL-RL computational engine employs a scenario generator that feeds the Freeway Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived. The STREETVAL-RL computational engine employs a scenario generator that feeds the Urban Streets Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived.
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incorporating travel time reliability into the Highway Capacity Manual
SHRP 2 Report, 2014Co-Authors: John D Zegeer, Paul Ryus, Mark Vandehey, Richard G Dowling, James A Bonneson, Wayne Kittelson, Nagui M. Rouphail, Bastian J Schroeder, Ali Hajbabaie, Behzad AghdashiAbstract:This publication presents a summary of the work conducted during the development of two proposed new chapters for the Highway Capacity Manual 2010 (HCM2010). These chapters demonstrated how to apply travel time reliability methods to the analysis of freeways and urban streets. The two proposed HCM chapters, numbers 36 and 37, introduce the concept of travel time reliability and offer new analytic methods. The prospective Chapter 36 for HCM2010 concerns freeway facilities and urban streets, and the prospective supplemental Chapter 37 elaborates on the methodologies and provides an example calculation. The chapters are proposed; they have not yet been accepted by the Transportation Research Board's Highway Capacity and Quality of Service (HCQS) Committee. The HCQS Committee has responsibility for approving the content of HCM2010. The second Strategic Highway Research Program (SHRP 2) Reliability Project L08 has also released the FREEVAL and STREETVAL computational engines. The FREEVAL-RL computational engine employs a scenario generator that feeds the Freeway Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived. The STREETVAL-RL computational engine employs a scenario generator that feeds the Urban Streets Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived.
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Proposed Chapters for Incorporating Travel Time Reliability into the Highway Capacity Manual - Proposed Chapters for Incorporating Travel Time Reliability into the Highway Capacity Manual
2013Co-Authors: Paul Ryus, Mark Vandehey, Richard G Dowling, James A Bonneson, John D Zegeer, Wayne Kittelson, Nagui M. Rouphail, Bastian J Schroeder, Ali Hajbabaie, Behzad AghdashiAbstract:This document contains two proposed chapters for the Highway Capacity Manual (HCM) that introduce the concept of travel time reliability and offer new analytic methods. Proposed Chapters 36 and 37 set out methodologies for incorporating reliability into the HCM analytic procedures for freeway facilities and urban streets. The approach is to generate many freeway and urban street scenarios involving various causes of nonrecurring congestion, such as incidents, weather, and work zones, and use the scenarios as input to a computational engine to calculate travel time over a segment. The travel times for each scenario are used to construct a distribution of travel time from which reliability performance measures can be derived. Chapter 37 supplements Chapter 36. It provides reliability values for selected U.S. facilities, offers an alternative freeway incident prediction method, elaborates on the freeway and urban street scenario generators, explains how to measure reliability in the field, and gives an example problem. The chapters were prepared under the Transportation Research Board’s second Strategic Highway Research Program (SHRP 2) Project L08, Incorporation of Travel Time Reliability into the Highway Capacity Manual, but they have not been officially accepted by the Highway Capacity and Quality of Service (HCQS) Committee of the Transportation Research Board.
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proposed chapters for incorporating travel time reliability into the Highway Capacity Manual
SHRP 2 Report, 2013Co-Authors: Paul Ryus, Mark Vandehey, Richard G Dowling, James A Bonneson, John D Zegeer, Wayne Kittelson, Nagui M. Rouphail, Bastian J Schroeder, Ali Hajbabaie, Behzad AghdashiAbstract:This document contains two proposed chapters for the Highway Capacity Manual (HCM) that introduce the concept of travel time reliability and offer new analytic methods. Proposed Chapters 36 and 37 set out methodologies for incorporating reliability into the HCM analytic procedures for freeway facilities and urban streets. The approach is to generate many freeway and urban street scenarios involving various causes of nonrecurring congestion, such as incidents, weather, and work zones, and use the scenarios as input to a computational engine to calculate travel time over a segment. The travel times for each scenario are used to construct a distribution of travel time from which reliability performance measures can be derived. Chapter 37 supplements Chapter 36. It provides reliability values for selected U.S. facilities, offers an alternative freeway incident prediction method, elaborates on the freeway and urban street scenario generators, explains how to measure reliability in the field, and gives an example problem. The chapters were prepared under the Transportation Research Board’s second Strategic Highway Research Program (SHRP 2) Project L08, Incorporation of Travel Time Reliability into the Highway Capacity Manual, but they have not been officially accepted by the Highway Capacity and Quality of Service (HCQS) Committee of the Transportation Research Board.
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Estimation of Incident Propensity for Reliability Analysis in the Highway Capacity Manual
Transportation Research Record, 2013Co-Authors: Seyedbehzad Aghdashi, Nagui M. Rouphail, Ali HajbabaieAbstract:This paper presents the method used to generate the incident probabilities required by the freeway scenario generator for travel time reliability analysis in the Highway Capacity Manual. The freeway scenario generator requires the estimation of monthly probabilities of different levels of incident severity during specified study periods. Incident probability in this context is the fraction of time that an incident of a specific level of severity is active somewhere on the freeway facility during the study period for the month considered. The proposed method is designed to recognize and deal with the varying levels of incident and facility data availability at the implementing agencies. A queuing model is proposed for the conversion of incident frequencies into incident probabilities when agencies have access only to frequencies instead of probabilities.
Roger P Roess - One of the best experts on this subject based on the ideXlab platform.
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The Highway Capacity Manual and the Committee on Highway Capacity and Quality of Service
Springer Tracts on Transportation and Traffic, 2020Co-Authors: Elena S Prassas, Roger P RoessAbstract:The Highway Capacity Manual is one of the most fundamental documents used in the transportation and traffic engineering profession. It provides for the systematic design and evaluation of traffic facilities with regard to their Capacity, and the quality of traffic service provided to facility users. This chapter provides an overview and history of the document itself, and its development over the years.
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the Highway Capacity Manual a conceptual and research history volume 1 uninterrupted flow
2014Co-Authors: Roger P Roess, Elena S PrassasAbstract:Used as a standard in the planning, design, analysis and operation of Highway traffic facilities in the United States since 1950, the Highway Capacity Manual has also been widely used abroad and has inspired other countries to develop similar Manuals. The Manual has developed the twin concepts of level of service and Capacity, and it has presented methodologies that allow Highway traffic facilities to be designed on a common basis, as well as allowed for the analysis of operational quality under different traffic demand scenarios. Pedestrian, bicycle and transit issues are also addressed in this Manual. There are two volumes, the first of which (Volume 1) is this book. It focuses on the development of basic principles and their application to uninterrupted flow facilities, such as multilane Highways, two-lane Highways, and freeways. Also discussed in detail are merging, weaving and diverging segments on multilane Highways and freeways. In Volume 2 the focus is on interrupted flow facilities, such as unsignalized and signalized intersections, arterials, and urban streets.
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the Highway Capacity Manual a conceptual and research history
2014Co-Authors: Roger P Roess, Elena S PrassasAbstract:An Overview of the Highway Capacity Manual and Its History.- Highway Capacity Manual and Its History .- The Fundamental Concept of Capacity.- The Fundamental Concept of Level of Service.- Passenger Car Equivalents and Other Adjustment Factors.- Overview of Uninterrupted Flow Methodologies of the Highway Capacity Manual.- Speed-Flow-Density Relationships: The Fundamental 145 Basis of Uninterrupted Flow Analysis.- Basic Freeway and Multilane Highway Segments.- Analysis of Weaving Segments.- Analysis of Merge and Diverge Segments.- Analysis of Two-Lane, Two-Way Highways.- The Future of the Highway Capacity Manual. Highway Capacity Manual.
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Speed-Flow Curves for Freeways in Highway Capacity Manual 2010
Transportation Research Record, 2011Co-Authors: Roger P RoessAbstract:Since the 1965 edition of the Highway Capacity Manual (HCM), fundamental curves representing the relationship between speed and volume or flow rate have formed the basis of design and analysis methodologies for basic freeway segments and for uninterrupted flow segments of multilane Highways. As the 2010 edition of the HCM was being developed, a new set of freeway speed–flow curves was recommended. Somewhat late in the development process, the recommended curves became controversial. This paper presents the recommended curves and the research behind them and the controversies that affected the outcome. A final set of curves for HCM 2010 was recommended on the basis of extensive comparative statistical analyses of a substantial database and on several conditions that the TRB Highway Capacity and Quality of Service Committee voted to impose on the curves characteristics. Recommendations for the future are made.
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Highway Capacity Analysis After Highway Capacity Manual 2000
Transportation Research Record, 2001Co-Authors: Wayne Kittelson, Roger P RoessAbstract:The publication of the "fourth" full edition of the Highway Capacity Manual (HCM) in the fall of 2000 represented a major step forward in state-of-the-art Highway Capacity and quality-of-service analyses. Even as this major step is taken, however, old issues reemerge and new ones arise as to the core concepts involved, the directions that such analyses should take in the future, and the needs of HCM users. Now that HCM has begun to address system and multimodal measures, the nature and meaning of Capacity and level-of-service concepts need to be reexamined. The role of simulation must be more clearly defined, as must the limitations of more conventional Highway Capacity analyses. As databases improve, the question of statistical accuracy and stochastic variations in standard measures may seem more important, even though the inherent variability in traffic flow characteristics remains essentially unchanged. The need for software to implement ever more complex methodologies raises additional issues. As the ...
Lily Elefteriadou - One of the best experts on this subject based on the ideXlab platform.
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Defining, Measuring, and Modeling Capacity for the Highway Capacity Manual
Journal of Transportation Engineering Part A: Systems, 2017Co-Authors: Alexandra Kondyli, Lily Elefteriadou, Bryan St. George, Gina BonyaniAbstract:AbstractThe Highway Capacity Manual (HCM) is the publication used most often to estimate Capacity. Field measurements in previous research have shown that the capacities at several freeway bottlene...
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Proposed Framework for Evaluating Spillback in the Highway Capacity Manual
Transportation Research Record, 2017Co-Authors: Yinan Zheng, Michael Armstrong, Gustavo Riente De Andrade, Lily ElefteriadouAbstract:Procedures detailed in the Highway Capacity Manual 2010 (HCM 2010) estimate Capacity and several operational measures dictating level of service for freeway facilities and surface streets. However, these methods do not consider cases in which spillback occurs from one facility type to another. The queuing effects in oversaturated conditions as they propagate upstream onto a freeway main line or a surface street intersection are not accounted for. The objective of this paper is to propose a series of modifications to enhance the HCM 2010 methods to address spillback conditions. These modifications consider lane utilization and lane blockage under spillback conditions and consist of restructuring existing equations and reference tables as well as developing new procedures. A four-regime method is proposed for evaluating spillback effects from urban streets to diverge and weaving segments. In addition, a method is proposed to account for the spillback effects from freeway on-ramps by reducing the effective g...
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Proposed Framework for Evaluating Spillback in the Highway Capacity Manual
Transportation Research Record: Journal of the Transportation Research Board, 2017Co-Authors: Yinan Zheng, Michael Armstrong, Gustavo De Andrade, Lily ElefteriadouAbstract:Procedures detailed in the Highway Capacity Manual 2010 (HCM 2010) estimate Capacity and several operational measures dictating level of service for freeway facilities and surface streets. However, these methods do not consider cases in which spillback occurs from one facility type to another. The queuing effects in oversaturated conditions as they propagate upstream onto a freeway main line or a surface street intersection are not accounted for. The objective of this paper is to propose a series of modifications to enhance the HCM 2010 methods to address spillback conditions. These modifications consider lane utilization and lane blockage under spillback conditions and consist of restructuring existing equations and reference tables as well as developing new procedures. A four-regime method is proposed for evaluating spillback effects from urban streets to diverge and weaving segments. In addition, a method is proposed to account for the spillback effects from freeway on-ramps by reducing the effective green time as a proportion of the percent of time that the queue is expected to block the upstream signalized intersection. The framework developed uses assumptions that should be further explored through an extensive, nationwide data collection effort.
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The Highway Capacity Manual 6th Edition: A Guide for Multimodal Mobility Analysis
Ite Journal-institute of Transportation Engineers, 2016Co-Authors: Lily ElefteriadouAbstract:In designing new Highways or redesigning existing ones, it is essential to evaluate congested operations, to consider multiple modes and their interactions, and to use a variety of performance measures and tools, including simulation. To highlight those elements, the sixth edition of the Transportation Research Board's Highway Capacity Manual (HCM), scheduled for publication in 2016, will have the subtitle, "A Guide for Multimodal Mobility Analysis.” This edition of the HCM describes performance measures for various modes and facilities in addition to the well-known level of service (LOS). It provides travel time estimates for freeway systems in addition to urban streets, and performance measures for pedestrians, bicyclists and transit users. This article provides an overview of the new edition and will familiarize practitioners and researchers with the set of analysis tools in the new HCM.
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Exploring Multimodal Analysis in the Highway Capacity Manual 2010
Ite Journal-institute of Transportation Engineers, 2015Co-Authors: Lily Elefteriadou, Richard G Dowling, Paul RyusAbstract:Evaluating the operational effectiveness of Highway facilities is crucial, both in assessing existing conditions and identifying future needs. Operational analyses provided within the Highway Capacity Manual 2010 (HCM), also referred to as Highway Capacity analyses, estimate various performance measures such as queues, delays, and travel times as functions of the expected demand and geometry. They also estimate the level of service (LOS) as a function of one or more of these performance measures.
Berry Ives - One of the best experts on this subject based on the ideXlab platform.
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Implementation of Highway Capacity Manual–Based Volume-Delay Functions in Regional Traffic Assignment Process
Transportation Research Record: Journal of the Transportation Research Board, 1996Co-Authors: David L. Kurth, At Van Den Hout, Berry IvesAbstract:Recent model development efforts for the travel demand forecasting process have focused on increasing the consistency and reasonableness of the results. A major target of these efforts has been the traffic assignment process and, more specifically, improving the estimates of congested travel speeds resulting from traffic assignments. A number of studies and enhancements have centered on the volume-delay functions used for the assignment process. Many of these studies have used the workhorse volume-delay function, the BPR function, and have investigated modifications to the function coefficients. In its recent update of the Albuquerque Area Travel Models, the Middle Rio Grande Council of Governments successfully implemented a regional traffic assignment process based on Capacity estimation techniques and volume-delay functions documented in the Highway Capacity Manual. The assignment procedures developed for the Albuquerque area resulted in volume-delay functions that produced accurate traffic volumes while producing accurate congested speeds on the network. The Capacity estimation procedures increase the realism of the network representation and provide increased analysis flexibility. Commercially available travel demand modeling software has been used to implement the Highway Capacity Manual–based volume-delay functions.
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implementation of Highway Capacity Manual based volume delay functions in regional traffic assignment process
Transportation Research Record, 1996Co-Authors: David L. Kurth, At Van Den Hout, Berry IvesAbstract:Recent model development efforts for the travel demand forecasting process have focused on increasing the consistency and reasonableness of the results. A major target of these efforts has been the traffic assignment process and, more specifically, improving the estimates of congested travel speeds resulting from traffic assignments. A number of studies and enhancements have centered on the volume-delay functions used for the assignment process. Many of these studies have used the workhorse volume-delay function, the BPR function, and have investigated modifications to the function coefficients. In its recent update of the Albuquerque Area Travel Models, the Middle Rio Grande Council of Governments successfully implemented a regional traffic assignment process based on Capacity estimation techniques and volume-delay functions documented in the Highway Capacity Manual. The assignment procedures developed for the Albuquerque area resulted in volume-delay functions that produced accurate traffic volumes whil...
Bastian J Schroeder - One of the best experts on this subject based on the ideXlab platform.
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Evaluating the Operational Effect of Narrow Lanes and Shoulders for the Highway Capacity Manual
Transportation Research Record: Journal of the Transportation Research Board, 2019Co-Authors: Alexandra Kondyli, Bastian J Schroeder, David K. Hale, Mohamadamin Asgharzadeh, Anxi Jia, Joe G BaredAbstract:Unnecessary traffic delays and vehicle emissions have adverse effects on quality of life. To solve the traffic congestion problem in the U.S.A., mitigation or elimination of bottlenecks is a top priority. Agencies across the U.S.A. have deployed several congestion mitigation strategies, such as lane and shoulder width reduction, which aim to adding lanes without significantly altering the footprint of the freeway. A limited number of studies have evaluated the operational benefits of lane narrowing. Although the Highway Capacity Manual does account for lane and shoulder widths, the adjustments that it provides are outdated. The goal of this research was to develop analytical models, compatible with the Highway Capacity Manual methods, to account for lane and shoulder width narrowing, using field data from across the U.S.A. This paper presents a new free-flow speed regression model, which accounts for lane and shoulder widths, and Capacity adjustment factors depending on the lane width.
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Incorporating Travel Time Reliability into the Highway Capacity Manual - Incorporating travel time reliability into the Highway Capacity Manual.
2014Co-Authors: John D Zegeer, Paul Ryus, Mark Vandehey, Richard G Dowling, James A Bonneson, Wayne Kittelson, Nagui M. Rouphail, Bastian J Schroeder, Ali Hajbabaie, Behzad AghdashiAbstract:This publication presents a summary of the work conducted during the development of two proposed new chapters for the Highway Capacity Manual 2010 (HCM2010). These chapters demonstrated how to apply travel time reliability methods to the analysis of freeways and urban streets. The two proposed HCM chapters, numbers 36 and 37, introduce the concept of travel time reliability and offer new analytic methods. The prospective Chapter 36 for HCM2010 concerns freeway facilities and urban streets, and the prospective supplemental Chapter 37 elaborates on the methodologies and provides an example calculation. The chapters are proposed; they have not yet been accepted by the Transportation Research Board's Highway Capacity and Quality of Service (HCQS) Committee. The HCQS Committee has responsibility for approving the content of HCM2010. The second Strategic Highway Research Program (SHRP 2) Reliability Project L08 has also released the FREEVAL and STREETVAL computational engines. The FREEVAL-RL computational engine employs a scenario generator that feeds the Freeway Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived. The STREETVAL-RL computational engine employs a scenario generator that feeds the Urban Streets Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived.
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incorporating travel time reliability into the Highway Capacity Manual
SHRP 2 Report, 2014Co-Authors: John D Zegeer, Paul Ryus, Mark Vandehey, Richard G Dowling, James A Bonneson, Wayne Kittelson, Nagui M. Rouphail, Bastian J Schroeder, Ali Hajbabaie, Behzad AghdashiAbstract:This publication presents a summary of the work conducted during the development of two proposed new chapters for the Highway Capacity Manual 2010 (HCM2010). These chapters demonstrated how to apply travel time reliability methods to the analysis of freeways and urban streets. The two proposed HCM chapters, numbers 36 and 37, introduce the concept of travel time reliability and offer new analytic methods. The prospective Chapter 36 for HCM2010 concerns freeway facilities and urban streets, and the prospective supplemental Chapter 37 elaborates on the methodologies and provides an example calculation. The chapters are proposed; they have not yet been accepted by the Transportation Research Board's Highway Capacity and Quality of Service (HCQS) Committee. The HCQS Committee has responsibility for approving the content of HCM2010. The second Strategic Highway Research Program (SHRP 2) Reliability Project L08 has also released the FREEVAL and STREETVAL computational engines. The FREEVAL-RL computational engine employs a scenario generator that feeds the Freeway Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived. The STREETVAL-RL computational engine employs a scenario generator that feeds the Urban Streets Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived.
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Proposed Chapters for Incorporating Travel Time Reliability into the Highway Capacity Manual - Proposed Chapters for Incorporating Travel Time Reliability into the Highway Capacity Manual
2013Co-Authors: Paul Ryus, Mark Vandehey, Richard G Dowling, James A Bonneson, John D Zegeer, Wayne Kittelson, Nagui M. Rouphail, Bastian J Schroeder, Ali Hajbabaie, Behzad AghdashiAbstract:This document contains two proposed chapters for the Highway Capacity Manual (HCM) that introduce the concept of travel time reliability and offer new analytic methods. Proposed Chapters 36 and 37 set out methodologies for incorporating reliability into the HCM analytic procedures for freeway facilities and urban streets. The approach is to generate many freeway and urban street scenarios involving various causes of nonrecurring congestion, such as incidents, weather, and work zones, and use the scenarios as input to a computational engine to calculate travel time over a segment. The travel times for each scenario are used to construct a distribution of travel time from which reliability performance measures can be derived. Chapter 37 supplements Chapter 36. It provides reliability values for selected U.S. facilities, offers an alternative freeway incident prediction method, elaborates on the freeway and urban street scenario generators, explains how to measure reliability in the field, and gives an example problem. The chapters were prepared under the Transportation Research Board’s second Strategic Highway Research Program (SHRP 2) Project L08, Incorporation of Travel Time Reliability into the Highway Capacity Manual, but they have not been officially accepted by the Highway Capacity and Quality of Service (HCQS) Committee of the Transportation Research Board.
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proposed chapters for incorporating travel time reliability into the Highway Capacity Manual
SHRP 2 Report, 2013Co-Authors: Paul Ryus, Mark Vandehey, Richard G Dowling, James A Bonneson, John D Zegeer, Wayne Kittelson, Nagui M. Rouphail, Bastian J Schroeder, Ali Hajbabaie, Behzad AghdashiAbstract:This document contains two proposed chapters for the Highway Capacity Manual (HCM) that introduce the concept of travel time reliability and offer new analytic methods. Proposed Chapters 36 and 37 set out methodologies for incorporating reliability into the HCM analytic procedures for freeway facilities and urban streets. The approach is to generate many freeway and urban street scenarios involving various causes of nonrecurring congestion, such as incidents, weather, and work zones, and use the scenarios as input to a computational engine to calculate travel time over a segment. The travel times for each scenario are used to construct a distribution of travel time from which reliability performance measures can be derived. Chapter 37 supplements Chapter 36. It provides reliability values for selected U.S. facilities, offers an alternative freeway incident prediction method, elaborates on the freeway and urban street scenario generators, explains how to measure reliability in the field, and gives an example problem. The chapters were prepared under the Transportation Research Board’s second Strategic Highway Research Program (SHRP 2) Project L08, Incorporation of Travel Time Reliability into the Highway Capacity Manual, but they have not been officially accepted by the Highway Capacity and Quality of Service (HCQS) Committee of the Transportation Research Board.