NTERNATIONAL EDITION TRAFFIC ENGINEERING TRAFFIC ENGINEERING THIRD EDITION ROGER P ROESS ELENA S.PRASSAS 2 WILLIAM R:MCSHANE E PEARSON
(1 Leaye w心9sje以-d,9, )C。5 Traffic Engineering Third Edition Roger P.Roess Professor of Transportation Engineering Polytechnic University Elena S.Prassas Associate Professor of Transportation Engineering Polytechnic University William R.McShane Professor of Transportation and System Engineering Polytechnic University PEARSON Pearson Education International
If you purchased this book within the United Statesor Canada Vice President and Editorial Director,ECS:Marcia Horton Vice President and Director of Production and Manufacturing.ESM:David W.Riccardi Acquisitions Editor:Laura Fischer Editorial Assistant:Andrea Messineo Executive Managing Editor:Vince O'Brien Managing Editor:David A.George Production Editor:Rose Kernan Director of Creative Services:Paul Belfanti Creative Director:Carole Anson Art Director:Jayne Conte Cover Designer:Bruce Kenselaar Ant Editor:Connie Long Manufacturing Manager:Trudy Pisciotti Manufacturing Buyer:Lisa McDowell Marketing Manager:Holly Stark PEARSON 2004 by Pearson Education,Inc. Pearson Prentice Hall Prentice Pearson Education,Inc. Upper Saddle River.New Jersey 07458 All rights reserved.No part of this book may be reproduced or transmitted in any form or by any means,without permission in writing from the publisher Pearson Prentice Hall is a trademark of Pearson Education,Inc. The author and publisher of this book have used their best efforts in preparing this book.These efforts include the develop- ment,research,and testing of the theories and programs to determine their effectiveness.The author and publisher shall not be idental or consequential damages with,or arising out of the furnishing performance,or use of these programs Printed in the United States of America 10987654321 ISBN0-13-191877-X Ld:,Sydney Hong Kong No e lucat ducation- aysia,Pte
If you purchased this book within the United States or Canada you should be aware that it has been wrongfully imported without the approval of the Publisher or the Author. Vice President and Editorial Director, ECS: Marcia Horton Vice President and Director of Production and Manufacturing, ESM: David IiI! Riccardi Acquisitions Editor: hura Fischer Editorial Assistant: Andrea Messineo Executive Managing Editor: Vince 0 'Brien Managing Editor: David A. George Production Editor: Rose Kernan Director of Creative Services: Paul Belfanti Creative Director: Carole Anson Art Director: Jayne Conte Cover Designer: Bruce Kenselaar Art Editor: Connie Long Manufacturing Manager: Trudy Pisciotti Manufacturing Buyer: Lisa McDowell Marketing Manager: Holly Stark O 2004 by Pearson Education, Inc. Pearson Prentice Hall Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, without permission in writing from the publisher. Pearson Prentice all' is a trademark of Pearson Education, Inc. The author and publisher of this book have used their best efforts in preparing this book. These efforts include the development, research, and testing of the theories and programs to determine their effectiveness. The author and publisher shall not be liable in any event for incidental or consequential damages with, or arising out of, the furnishing, performance, or use of these programs. Printed in the United States of America ISBN 0-13-191877-X Pearson Education Ltd., London Pearson Education Australia Pty., Ltd:, Sydney Pearson Education Singapore, Pte. Ltd. Pearson Education North Asia Ltd., Hong Kong Pearson Education Canada, Inc., Toronto Pearson Educaci6n de Mexico, S.A. de C.V. Pearson Education-Japan, Tokyo Pearson Education Malaysia, Pte, Ltd. Pearson Education, Inc., Upper Saddle Rive!; New Jersey
Contents Preface xiii 1 Introduction to Traffic Engineering Uniformity 18 2.2 1.1.3 Responsibility,Ethics,and Liability Important Visual Deficits 21 n Tra 12 Deman 2.2.61m 122C on Road Users 26 22.7 Psychological,P 23 Vehicles Related Factor 1.3 Highway Legislation and History 2.3.1 Concept of the Design Vehicle 27 and the Rights Issue 2.3.3 Braking Characteristics 31 32 2.4 234 2.4.1 Safe sto 33 nse Highways 243 Sigh Distance3 Applications 34 1.6 Star 2.4.4Ch ard R 11 Metric versus U.S.Units 15 Signal 35 Closing Comments 36 Problems37 Part 1 Components of the Traffic System and their Characteristics 16 Roadwaysand Their 2 Road User and Vehicle Characteristics 17 道
Contents Preface xiii 1 Introduction to Traffic Engineering 1.1 Traffic Engineering as a Profession 1 1.1.1 Safety: The Primary Objective 1.1.2 Other Objectives 2 1 1 1.1.3 Responsibility, Ethics, and Liability in Traffic Engineering 2 1.2.1 The Nature of Transportation 1.2.2 Concepts of Mobility 1.2.3 People, Goods, and Vehicles 6 1.2.4 Transportation Modes 7 1.3 Highway Legislation and History 1.2 Transportation Systems and their Function 3 Demand 4 and Accessibility 5 in the United States 7 Rights Issue 7 1.3.1 1.3.2 Key Legislative Milestones 10 1.3.3 The National Pike and the States’ The National System of Interstate and Defense Highways 11 1.4 Elements of Traffic Engineering 13 1.5 1.6 1.7 Metric versus U.S. Units 15 1.8 Closing Comments 15 References 15 Modern Problems for the Traffic Standard References for the Traffic Engineer 14 Engineer 14 Part 1 Components of the Traffic System 2 Road1 User and Vehicle Characteristics 17 and their Characteristics 16 2.1 Overview of Traffic Stream Components 17 2.1.1 Dealing with Diversity 17 2.1.2 Addressing Diversity Through Uniformity 18 2.2 Road Users 18 2.2.1 Visual Characteristics of Drivers 19 2.2.2 Important Visual Deficits 21 2.2.3 Perception-Reaction Time 21 2.2.4 Pedestrian Characteristics 23 2.2.5 Impacts of Drugs and Alcohol 2.2.6 Impacts of Aging on Road Users 26 2.2.7 Psychological, Personality, and Related Factors 26 on Road Users 25 2.3 Vehicles 27 2.3.1 Concept of the Design Vehicle 27 2.3.2 Turning Characteristics of Vehicles 28 2.3.3 Braking Characteristics 3 1 2.3.4 Acceleration Characteristics 32 2.4 Total Stopping Distance and Applications 33 2.4.1 Safe Stopping Sight Distance 33 2.4.2 Decision Sight Distance 34 2.4.3 Other Sight Distance Applications 34 2.4.4 Change (Yellow) and Clearance (All Red) Intervals for a Traffic Signal 35 2.5 Closing Comments 36 References 36 Problems 37 3 Roadways and Their Geometric Characteristics 38 3.1 Highway Functions and Classification 38 3.1.1 Trip Functions 38 . 111
CONTENTS way Classification 39 415C 4.2 76 32 42 422 423 78 322 425 Object Marker 1 4.3 Traffic Signs 83 32.3 Introductin Cross-ectional 432 Regulatory Signs 324 Surveving and Stationing 43 4.3.3 Guide Signs 88 44 4.4.2 Pedest 444 Oth 4.5 Special T s of Control 103 3.3.4 Compound HorizontalCurves 57 4.6 Summary nd Conclusion 103 34 se Ho 58 5 Traffic Stream Characteristics 105 3.43 106 106 Controls on Length of Vertical Curves 64 22 345 Some Design 52.3 Density and o cupancy 112 5.2.4 35 Cro ss-Section Elements of Highways65 g and H 53 114 Relatio nong Flow Spee 353 Side-Slones for Cuts 18 6 3.6 ents 69 6 Intelligent TransportationSystems 120 121 4 Introduction to Traffic Control Devices 71 4.1 Route 1230na 124 istory and Ba MUTCD 6> ronic Toll Colle The Smart Card 126 6.10 Dynamic Assignment 126
CONTENTS 3.1.2 Highway Classification 39 3.1.3 Preserving the Function 3.2 Highway Design Elements 42 of a Facility 40 3.2.1 Introduction to Horizontal Alignment 42 3.2.2 Introduction to Vertical Alignment 43 3.2.3 Introduction to Cross-Sectional Elements 43 3.2.4 Surveying and Stationing 43 3.3 Horizontal Alignment of Highways 44 3.3.1 Geometric Characteristics of Horizontal Curves 44 3.3.2 Spiral Transition Curves 52 3.3.3 Sight Distance on Horizontal 3.3.4 Compound Horizontal Curves 57 3.3.5 Reverse Horizontal Curves 57 3.4.1 Grades 58 3.4.2 Geometric Characteristics of Vertical Curves 6 1 3.4.3 Sight Distance on Vertical Curves 63 3.4.4 of Vertical Curves 64 3.4.5 Some Design Guidelines for Vertical Curves 65 Curves 55 3.4 Vertical Alignment of Highways 58 Other Minimum Controls on Length 3.5 Cross-Section Elements of Highways 65 3.5.1 Travel Lanes and Pavement 65 3.5.2 Shoulders 66 3.5.3 Side-Slopes for Cuts 3.5.4 Guardrail 67 and Embankments 67 3.6 Closing Comments 69 References 69 Problems 70 4 Introduction to Traflic Control Devices 71 4.1 The Manual on Uniform Traffic Control Devices 71 4.1.1 History and Background 72 4.1.2 General Principles of the 4.1.3 Contents of the MUTCD 73 4.1.4 Legal Aspects of the MUTCD 74 MUTCD 72 4.1.5 Communicating with the Driver 75 4.2.1 Colors and Patterns 76 4.2.2 Longitudinal Markings 77 4.2.3 Transverse Markings 78 4.2.4 Object Markers 80 4.2.5 Delineators 8 1 4.3.1 Regulatory Signs 83 4.3.2 Warning Signs 87 4.3.3 Guide Signs 88 4.4.1 Traffic Control Signals 94 4.4.2 Pedestrian Signals 100 4.4.3 Other Traffic Signals 100 4.4.4 Trafi5c Signal Controllers 101 4.2 TrafficMarkings 76 4.3 Traffic Signs 83 4.4 Traffic Signals 94 4.5 Special Types of Control 103 4.6 Summary and Conclusion 103 References 104 Problems 104 5 Traffic Stream Characteristics 105 5.1 Types of Facilities 106 5.2 Traffic Stream Parameters 106 5.2.1 Volume and Rate of Flow 106 5.2.2 Speed and Travel Time 11 1 5.2.3 Density and Occupancy 112 5.2.4 Spacing and Headway: Microscopic Parameters 114 5.3 Relationships among Flow Rate, References 11 8 Problems 118 Speed, and Density 115 6 Intelligent Transportation Systems 120 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 The Range of ITS Applications Network Optimization 122 Sensing Traffic using Virtual Detectors In-Vehicle Routing, and Personal The Smart Car 124 Commercial Routing and Delivery 124 Electronic Toll Collection 125 The Smart Card 125 Congestion Pricing 126 Dynamic Assignment 126 121 122 Route Information 123
CONTENTS Reference 127 6.13 Emerging Issu 127 8 Volume Studies and Characteristics 159 6.14 Summary Problems 12 8.1 160 Part 2 Traffic Studies and Programs 130 Types of Studies 7 82.1 Volume,Demand,and Capacity 162 8.2.2 166 7 1 An Overview of Probability Functions 8.3 Field Techniques for Volume Studies 172 132 8.31 nual Count Techniques 173 iosSgtinuous 7.1.2 Randomnessand Distributions 8.4 Intersection Volume Studies 178 32 8.4.1 mes 7.1.4 133 Studies 12 178 8.42 sfor Signalize 135 1 8.4.3 Presentatio n of Inter ction 7.2.21m tion 135 8.5 Limited N me s of the Normal Distribution rage Counts 13143 Confidence Bo 138 P Sample Size Computations 139 51 twork 18 140 8.5.5 7.6 7.6.1 Bernoulliand the Binomial actors 189 141 8.6.2 Calibrating M 762 8.6.3Gro ing Data from Control 凤and the Norma 8641 Coun ocations 9/91 The Poisson Distribution 143 865 Estimating Annual Vehicle-Miles Tests with Two Specialized 103 t Ch 145 8.7.1 Origin and DestinationCounts 193 7.82 h nd-AferT S.Cordon 196 198 147 8.8 Closing Comments 200 7.9 and Closing C
CONTENTS V 6.11 Traffic Enforcement 127 6.12 Bus Transit and Paratransit 127 6.13 Emerging Issues 127 6.14 Summary 128 References 128 Problems 129 Part 2 Traffic Studies and Programs 7 Statistical Applications in Traffic 130 Engineering 131 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 An Overview of Probability Functions 7.1.1 Discrete versus Continuous Functions 132 7.1.2 Randomness and Distributions Describing Randomness 132 7.1.3 Organizing Data 132 7.1.4 Common Statistical Estimators 133 The Normal Distribution and Its Applications 135 7.2.1 The Standard Normal Distribution 135 7.2.2 Important Characteristics of the Normal Distribution Function 138 Confidence Bounds 138 Sample Size Computations 139 Addition of Random Variables 139 7.5.1 The Central Limit Theorem 140 The Binomial Distribution Related to the Bernoulli and Normal Distributions 141 7.6.1 Bernoulli and the Binomial 7.6.2 Asking People Questions: 7.6.3 The Poisson Distribution 143 Hypothesis Testing 144 7.8.1 Before-and-After Tests with Two 7.8.2 Before-and-After Tests and Statistics 132 Distribution 141 Survey Results 143 Distributions 143 The Binomial and the Normal Distinct Choices 145 with Generalized Alternative Hypothesis 147 7.8.3 Other Useful Statistical Tests 149 Summary and Closing Comments 156 References 156 Problems 156 8 Volume Studies and Characteristics 159 8.1 Introduction to Traffic Studies 159 8.1.1 Modern Technology 160 8.1.2 Types of Studies 160 8.2 Volume Characteristics 161 8.2.1 Volume, Demand, and Capacity 162 8.2.2 Volume Patterns and Characteristics 166 8.3 Field Techniques for Volume Studies 172 8.3.1 Manual Count Techniques 173 8.3.2 Portable Count Techniques 176 8.3.3 Permanent Counts 177 8.4.1 Arrival versus Departure Volumes: 8.4 Intersection Volume Studies 178 A Key Issue for Intersection Studies 178 Intersections 179 Volume Data 179 8.5.1 Control Counts 182 8.5.2 Coverage Counts 182 8.5.3 An Illustrative Study 182 8.5.4 Estimating Vehicle Miles Traveled 8.5.5 Display of Network 8.4.2 Special Considerations for Signalized 8.4.3 Presentation of Intersection 8.5 Limited Network Volume Studies 180 (VMT) on a Network 186 Volume Results I86 8.6 Statewide Counting Programs 186 8.6.1 Calibrating Daily Variation Factors 189 8.6.2 Calibrating Monthly Variation Factors 189 8.6.3 Grouping Data from Control Count Locations 191 8.6.4 Using the Results 192 8.6.5 Estimating Annual Vehicle-Miles Traveled 192 8.7 Specialized Counting Studies 193 8.7.1 Origin and Destination Counts 193 8.7.2 Cordon Counts 196 8.7.3 Screen-Line Counts 198 8.8 Closing Comments 200 References 200 Problems 200
vi CONTENTS 9 104 5 Before-and-AfterAcciden 203 Analysis 251 92 Introduction 203 10.5 253 10.5.2 Condition Diagrams 255 0.5.3 Uses of Spot Speed Data 205 lnterpreationc 255 20 of Spot Speed Data 208 189m2分 omments 9.3 Travel-Time Studies 222 11 Parking Facilities.and Prog An Example of the Statistics 122 Parking Gener vel- Time Data 113 Parking Studiesand Char cteristics 270 228 11.3.1 Proximity:How Far Will 9.4 11.3.2 Parking Inventories 270 Closing Comments 233 13 Accumulatior 272 23对 76 1141 f Park cilities 21m 10 Accidents:Studies,Statistics, Some Ba Parking Dimensions 278 and Programs 236 43 102 Introduction 6 ehicle Areas f%8238 1.44 Parking Gara 11.5 102.2 11.6 Closing Comments 10.2.3 Behavior Modification39 240 Part 3 Applications to F Highway Systems 28geway and Rural 242 12 iceAnalysi 290 4 cms 243 12.1 Introductio 10.3.3 rd Systems 244 104 Computer Rec 12.1.1 The capa ty Conce 291 1041 of Statistics I-S 213 their Use 248 Analysis 29. 122
vi CONTENTS 9 Speed, Travel Time, and Delay Studies 203 9.1 Introduction 203 9.2 Spot Speed Studies 204 9.2.1 Speed Definitions of Interest 204 9.2.2 Uses of Spot Speed Data 205 9.2.3 Measurement Techniques 205 9.2.4 Reduction and Analysis of Spot Speed Data 208 9.2.5 Proper Location for Speed Studies 221 9.3 Travel-Time Studies 222 9.3.1 Field Study Techniques 222 9.3.2 Travel Time Data Along an Arterial: An Example of the Statistics of Travel Times 223 9.3.3 Overriding Default Values: Another Example of Statistical Analysis of Travel-Time Data 225 9.3.4 Travel-Time Displays 227 9.4 Intersection Delay Studies 228 9.5 Closing Comments 233 References 233 Problems 233 10 Accidents: Studies, Statistics, and Programs 236 10.1 Introduction 236 10.2 Approaches to Highway Safety 238 10.2.1 10.2.2 10.2.3 10.2.4 10.2.5 10.2.6 10.2.7 -. Exposure Control 238 Accident Risk ControVAccident Prevention 239 Behavior Modification 239 Injury Control 240 Post-Injury Management 240 Planning Actions to Implement Policy National Policy Initiatives 242 Strategies 240 10.3 Accident Data Collection and Record 10.3.1 Accident Reporting 242 10.3.2 Manual Filing Systems 243 10.3.3 Computer Record Systems 244 10.4.1 Types of Statistics 246 10.4.2 Accident Rates 247 10.4.3 Statistical Displays and their Use 248 10.4.4 Identifying High-Accident Systems 242 10.4 Accident Statistics 246 Locations 249 10.4.5 Before-and-After Accident Analysis 251 10.5 Site Analysis 253 10.5.1 Collision Diagrams 253 10.5.2 Condition Diagrams 255 10.5.3 Interpretation of Condition 10.6 Development of Countermeasures 257 10.7 Closing Comments 257 References 257 Problems 261 and Collision Diagrams 255 11 Parking: Studies, Characteristics, Facilities, and Programs 263 1 1.1 Introduction 263 1 1.2 Parking Generation and Supply Needs 264 1 1.2.1 Parking Generation 264 11.2.2 Zoning Regulations 267 11.3 Parking Studies and Characteristics 270 11.3.1 Proximity: How Far Will Parkers Walk? 270 11.3.2 Parking Inventories 270 11.3.3 Accumulation and Duration 272 11.3.4 Other Types of Parking Studies 276 11.4 Design Aspects of Parking Facilities 277 11.4.1 Some Basic Parking Dimensions 278 1 1.4.2 Parking Modules 279 1 1.4.3 Separating Small and Large Vehicle Areas 280 11.4.4 Parking Garages 283 11.5 Parking Programs 283 11.6 Closing Comments 286 References 286 Problems 286 Part 3 Applications to Freeway and Rural 12 Capacity and Level-of-Service Analysis Highway Systems 289 for Freeways and Multilane Highways 290 12.1 Introduction to Capacity and Level- 12.1.1 The Capacity Concept 291 12.1.2 The Level-of-Service Concept 292 12.1.3 The v/c Ratio and Its Use in Capacity of-Service Concepts 290 Analysis 294 12.2 Freeways and Multilane Highways 295 12.2.1 Facility Types 295
CONTENTS vii 1222B8aMg25 13.5.4 Det e in the Ramp Influence 13.5.5 De kpected Speed 358 36356 Special Cases 359 123 Deh Drive Poplaio actor ple ar 13.7.2 Analysis Models 371 rati 25 Cab Sped-Flow 12.5.3 Calibrati 4Tm"ggrRan 254Adom5rasofeto 32 02、393 144号 Cap 。395 306 Weaving,Merging,and Diverging 14.4.3 of Anal 39 14.4.4 Free-Flow Speed 397 1446 13.1 Turbulence Areasn Freeways 14.4.7 Determining Pere ent Time Spent ltilar 0 .0 1448 s of Pas anes 418 14.4.9 Impact tof Climbing Lanes 42 42 Demand 13.4 330 Flows in a Weaving Area 339 Problems 422 0 15 Signing and Marking for Freeways 345 and Rural Highways 424 Colng Areas to 424 and OtherTypes Freeway Markine 424 13.5 Ana and Divs Rural F Areas 351 way Marki 13.5.1 Strueture of the Methodolog 15.2 Establishingand Posting of Speed of Merge ad Diverge 428 53 Guide Freeways and Rural 431 13.5.3 Capaci ity Cons ation erence High Systems 431
CONTENTS vii 12.2.2 Basic Freeway and Multilane Highway Characteristics 295 Analysis Methodologies for Basic Freeway Sections and Multilane Highways 299 12.3 12.3.1 12.3.2 12.3.3 12.3.4 Types of Analysis 301 Determining the Free-Flow Speed 303 Determining the Heavy-Vehicle Determining the Driver Population Factor 308 Factor 315 12.4 Sample Applications 3 15 12.5 Calibration Issues 322 12.5.1 Calibrating Base Speed-Flow Curves 322 12.5.2 Calibrating Passenger Car Equivalents 328 12.5.3 Calibrating the Driver Population Factor 331 12.5.4 Adjustment Factors to Free-Flow Speed 331 12.6 Software 332 References 332 Probllems 333 13 Weaiving, Merging, and Diverging M:ovements on Freeways arid Multilane Highways 335 13.1 Turbulence Areas on Freeways 13.2 Level-of-Service Criteria 337 13.3 A Common Point: Converting 13.4 Analysis of Weaving Areas 338 and Multilane Highways 335 Demand Volumes 338 13.4.1 Flows in a Weaving Area 339 13.4.2 Critical Geometric Variables 340 13.4.3 Computational Procedures 13.4.4 Multiple Weaving Areas 350 13.4.5 Weaving on Collector-Distributor Roadways and Other Types of Facilities 350 for Weaving Area Analysis 345 13.5 Analysis of Merge and Diverge Areas 351 13.5.1 Structure of the Methodology for Analysis of Merge and Diverge Areas 351 13.5.2 Estimating Demand Flow Rates in Lanes 1 and 2 352 13.5.3 Capacity Considerations 357 13.5.4 Determining Density and Levelof-Service in the Ramp Influence Area 358 13.5.5 Determining Expected Speed Measures 358 13.5.6 Special Cases 359 13.6 Sample Problems in Weaving, Merging, 13.7 Analysis of Freeway Facilities 370 and Diverging Analysis 360 13.7.1 Segmenting the Freeway 370 13.7.2 Analysis Models 371 References 37 1 Problems 372 14 Two-Lane, Two-way Rural Highways 389 14.1 Introduction 589 14.2 Design Standards 390 14.3 Passing Sight Distance on Rural Two-Lane Highways 393 14.4 Capacity and Level-of-Service Analysis of Two-Lane Rural Highways 394 14.4.1 Capacity 395 14.4.2 Level-of-Service 396 14.4.3 Types of Analysis 397 14.4.4 Free-Flow Speed 397 14.4.5 Estimating Demand Flow Rate 399 14.4.6 Estimating Average Travel Speed 405 14.4.7 Determining Percent Time Spent Following 409 14.4.8 Impacts of Passing Lanes 418 14.4.9 Impact of Climbing Lanes 421 14.5 Summary 421 References 422 Problems 422 15 Signing and Marking for Freeways and Rural Highways 424 15.1 Traffic Markings on Freeways and Rural Highways 424 15.1.1 Freeway Markings 424 15.1.2 Rural Highway Markings 424 15.1.3 Ramp Junction Markings 427 Establishing and Posting of Speed Guide Signing of Freeways and Rural 15.3.1 Reference Posts 431 15.3.2 Numbered Highway Systems 431 15.2 15.3 Limits 428 Highways 431
viⅷ CONTENTS 15.3.3 Exit Numbering Systems 432 1724 Total Lost Time and the Concep 535 of Effective Green Time 475 Signing 436 17.2.6 Notable Studies on Saturation 15.4 Other Signs on Freeways and Rural 17.3 The Critical-Lane and Time-Budget mum Sum ofcriticalI an Part 4 applications to Urban and suburban Vomene Vi of Street Systems 444 Length 16 Introduction to Intersection Control 445 orehauwalengy 46 175 Types of Delay 163 Level conro YIELD ad STOP 17.5.2 Bas ore Models 16.3htrol 44 STOP Con 49 175.3 Inconsistencies in Random 16.32 YIELD Control l64,163 452 452 16.41 s of Traffic Signal 17.6 Overview 96 45 Traffic Signal Problems 497 16.43 Warants for Traffic Signals 454 18 Fundamentals of Signal Timing nd Design 500 1645 Samp Probmnpplication 181 501 181 mments 18.12Gc eral Consic ations in Signal 0 Problems 466 18.1.3 Phase and Ring Diagrams 503 18.1.4Com 17 Basic Principles of Intersection Signalization 470 18.1.5 Summary and Conclusion 515 470 515 Signal 18.2.1 Change and Clearance Intervals 515 17.1 ypes of Signal nent Left Turns 1823 ciaLane 17.2 Volumes 518 ost Times,and Car 473 1824 17.21 and Saturation Desired Cyele 18.2.5 Splitting the Green Clearance Lost Time 475
. Vlll CONTENTS 15.3.3 Exit Numbering Systems 432 15.3.4 Route Sign Assemblies 433 15.3.5 Freeway and Expressway Guide Signing 436 15.3.6 Guide Signing for Conventional Roads 441 15.4 Other Signs on Freeways and Rural References 442 Problems 442 Highways 441 Part 4 Applications to Urban and Suburban Street Systems 444 16 Introduction to Intersection Control 445 16.1 The Hierarchy of Intersection Control 445 16.2 Level I Control: Basic Rules of the Road 446 16.3 Level I1 Control: YIELD and STOP 16.3.1 Two-way STOP Control 449 16.3.2 YIELD Control 451 16.3.3 Multiway STOP Control 452 16.4 Level I11 Control: Traffic Control Signals 452 16.4.1 Advantages of Traffic Signal Control 453 16.4.2 Disadvantages of Traffic Signal Control 454 16.4.3 Warrants for Traffic Signals 454 16.4.4 Summary 462 16.4.5 Control 449 A Sample Problem in Application of Signal Warrants 463 16.5 Closing Comments 466 Refesences 466 Problems 466 17 Basic Principles of Intersection Signalization 470 17.1 Terms and Definitions 470 17.1.1 Components of a Signal Cycle 47 1 17.1.2 Types of Signal Operation 471 17.1.3 Treatment of Left Turns 472 Lost Times, and Capacity 473 17.2 Discharge Headways, Saturation Flow, 17.2.1 Saturation Headway and Saturation 17.2.2 Start-up Lost Time 474 17.2.3 Clearance Lost Time 475 Flow Rate 473 17.2.4 17.2.5 17.2.6 Notable Studies on Saturation Total Lost Time and the Concept Capacity of an Intersection Lane of Effective Green Time 475 or Lane Group 475 Headways, Flow Rates, and Lost Times 476 17.3 The Critical-Lane and Time-Budget Concepts 477 17.3.1 The Maximum Sum of Critical-Lane Volumes: One View of Signalized Intersection Capacity 479 17.3.2 Finding an Appropriate Cycle Length 480 17.4 The Concept of Left-Turn Equivalency 483 17.5 Delay as a Measure of Effectiveness 485 17.5.1 Types of Delay 486 17.5.2 Basic Theoretical Models 17.5.3 Inconsistencies in Random 17.5.4 Delay Models in the HCM 2000 494 17.5.5 Examples in Delay Estimation 495 of Delay 487 and Overflow Delay 493 17.6 Overview 496 References 497 Problems 497 18 Fundamentals of Signal Timing and Design 500 18.1 Development of Signal Phase Plans 501 18.1.1 Treatment of Left Turns 50 1 18.1.2 General Considerations in Signal Phasing 503 18.1.3 Phase and Ring Diagrams 503 18.1.4 Common Phase Plans 18.1.5 Summary and Conclusion 515 and Their Use 504 18.2 Determining Vehicular Signal Requirements 5 I5 18.2.1 Change and Clearance Intervals 515 18.2.2 Determining Lost Times 517 18.2.3 Determining the Sum of Critical-Lane Volumes 518 18.2.4 Determining the Desired Cycle Length 520 18.2.5 Splitting the Green 521 18.3 Determining Pedestrian Signal Requirements 522
CONTENTS ix 524 20.5 Examples in Actuated Signal Design and Timing 576 19 Elements of Intersection Desigr and Layout 540 21 Analysis of Signalized Intersections 585 191hmecmcanbregoe 21 1 Introduction 585 192 A 21.2 Conceptual Framework for the HCM 2000 ction 541 21.21700 nsignalized Intersections of Dema 586 2123Ca d Sa 1932 General Prin 21.2.4 Level-c 1933 Channelizing Right Tumns 546 1944 al Situations at Int sections 548 2125 548 1942 21.3 The Rasie 550 2131 Model Structure 591 19.4.3 593 1944 Special Treatments for Heavy 21 Analysis Time Periods 555 21.3.4 The Volum 597 195 21.3.5 The Saturation Flow Rate Module 599 Closing Comments63 713 isis Mo 2138 Interpretingthe Results of Signalized 214 Analysis 20AbdcCg 21.4.1 Sample Problem 1:Intersection 2142sa0 Signal with no permitted left tection ur 617 21.4.3Sa with initial oueues 620 taicdControlerFeatures 62 20.Actuated Signal Timing and Design 572 for Permitted Left Tums 628 se Plans 572 572 20.43 Init or vebicle Extension 572 on vs Rati 21624A TieofAgaodSignas639 20.4.6 Maximum Green Times 21.6.1 Measuring Prevailing Critical Cyel 21.6.2M Saturation Flow Rates639 for Actuated Signals 576 Flow Rates 640
CONTENTS ix 18.4 Sample Signal Timing Applications 524 References 536 Problems 537 19 Elements of Intersection Design amid Layout 540 19.1 Intersection Design Objectives and Considerations 540 19.2 A Basic Starting Point: Sizing the Intersection 541 19.2.1 Unsignalized Intersections 541 19.2.2 Signalized Intersections 543 19.3 Intersection Channelization 544 19.3.1 General Principles 544 19.3.2 Some Examples 544 19.3.3 Channelizing Right Turns 546 19.4 Special Situations at Intersections 548 19.4. I Intersections at Skewed Angles 548 19.4.2 T-Intersections: Opportunities 19.4.3 Offset Intersections 55 1 19.4.4 Special Treatments for Heavy for Creativity 550 Left-Turn Movements 555 19.5 Street Hardware for Signalized Intersections 558 19.6 Closing Comments 563 References 563 Problems 564 20 Actuated Signal Control arid Detection 565 20.1 20.2 20.3 20.4 Types of Actuated Control 566 Detectors and Detection 567 Actuated Control Features and Operation 568 20.3.1 Actuated Controller Features 569 20.3.2 Actuated Controller Operation 570 Actuated Signal Timing and Design 572 20.4.1 20.4.2 20.4.3 20.4.4 20.4.5 20.4.6 20.4.7 Phase Plans 572 Minimum Green Times 572 Unit or Vehicle Extension 572 Detector Location Strategies 573 Yellow and All-Red Intervals 574 Maximum Green Times and the Critical Cycle 575 Pedestrian Requirements for Actuated Signals 576 20.5 References 582 Problems 582 Examples in Actuated Signal Design and Timing 576 21 Analysis of Signalized Intersections 585 21.1 Introduction 585 21.2 Conceptual Framework for the HCM 2000 21.2.1 The Critical-Lane Group Concept 586 21.2.2 The v/s Ratio as a Measure 21.2.3 Capacity and Saturation Flow Rate 21.2.4 Level-of-Service Concepts 21.2.5 Effective Green Times Methodology 586 ofDemand 586 Concepts 587 and Criteria 590 and Lost Times 590 21.3 The Basic Model 591 21.3.1 Model Structure 591 21.3.2 Analysis Time Periods 593 21.3.3 The Input Module 593 21.3.4 The Volume Adjustment Module 597 21.3.5 The Saturation Flow Rate Module 599 2 1.3.6 Capacity Analysis Module 606 21.3.7 Level-of-Service Module 606 21.3.8 Interpreting the Results of Signalized Intersection Analysis 61 1 21.4 Some “Simple” Sample Problems 612 21.4.1 21.4.2 21.4.3 Sample Problem 1: Intersection of Two One-way Streets 612 Sample Problem 2: A Multiphase Signal with No Permitted Left Turns 617 with Initial Queues 626 Sample Problem 3: Dealing 21.5 Complexities 628 21.5.1 Left-Turn Adjustment Factor 21.5.2 Modeling Compound Phasing 634 21.5.3 Altering Signal Timings Based 21.5.4 Analysis of Actuated Signals 639 2 1.6.1 Measuring Prevailing 21.6.2 Measuring Base Saturation for Permitted Left Turns 628 on v/s Ratios 637 21.6 Calibration Issues 639 Saturation Flow Rates 639 Flow Rates 640