QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

QUADRANT ROADWAY INTERSECTION 

Informational Guide 

January 2020
QUADRANT ROADWAY INFORMATIONAL GUIDE

ii

U.S. Department of Transportation 

Federal Highway Administration Office of Safety 

1200 New Jersey Ave., SE 

Washington, DC 20590 

FOREWORD 

The Federal Highway Administration (FHWA) Every Day Counts (EDC) initiative is designed to 

identify and deploy innovation aimed at reducing project delivery time, enhancing safety and 

protecting the environment. In 2012, FHWA chose Intersection & Interchange Geometrics (IIG) 

to feature as one of the innovative technologies in the second round of EDC. Specifically, IIG 

consists of a family of alternative intersection designs that improve intersection safety while also 

reducing delay, lowering costs, and lessening impacts compared to traditional solutions. 

As part of the effort to mainstream these intersections, FHWA produced a series of informational 

guides to help transportation professionals routinely consider and implement these designs. 

During EDC2, FHWA developed and published guides for four designs: the Median U-Turn 

(MUT), Restricted Crossing U-turn (RCUT), Displaced Left Turn (DLT), and Diverging 

Diamond Interchange (DDI). This Quadrant Roadway (QR) Intersection Informational Guide is 

now the fifth in the series, and is intended to inform project planning, scoping, design and 

implementation decisions for QR intersections. 

An electronic version of this document is available on the Office of Safety website at 

http://safety.fhwa.dot.gov/. Additionally, limited quantities of hard copies are available from the 

Report Center; inquiries may be directed to report.center@dot.gov or 814-239-1160. 

Michael S. Griffith 

Director

Office of Safety Technologies 

Notice 

This document is disseminated under the sponsorship of the U.S. Department of Transportation 

in the interest of information exchange. The U.S. Government assumes no liability for the use of 

the information contained in this document. This report does not constitute a standard, 

specification, or regulation. 

The U.S. Government does not endorse products or manufacturers. Trademarks or 

manufacturers’ names appear in this report only because they are considered essential to the 

objective of the document. 

Quality Assurance Statement 

The Federal Highway Administration (FHWA) provides high-quality information to serve 

Government, industry, and the public in a manner that promotes public understanding. Standards 

and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its 

information. FHWA periodically reviews quality issues and adjusts its programs and processes to 

ensure continuous quality improvement. 
QUADRANT ROADWAY INFORMATIONAL GUIDE

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Technical Report Documentation Page 

1. Report No.

FHWA-SA-19-029 

2. Government Accession No. 3. Recipient’s Catalog No.

4. Title and Subtitle

Quadrant Roadway Intersection Informational Guide 

5. Report Date

January 2020 

6. Performing Organization Code

7. Authors

Jonathan D. Reid; Joseph E. Hummer 

8. Performing Organization Report No.

Project 13517 

9. Performing Organizations Name and Address 10. Work Unit No. (TRAIS)

Arcadis 

5420 Wade Park Drive, Suite 350 

Raleigh, North Carolina 27609 

VHB

940 Main Campus Drive #500 

Raleigh, NC 27606 

11. Contract or Grant No.

TO DTFH61-00023-T-13002 

12. Sponsoring Agency Name and Address

U.S. Department of Transportation 

Federal Highway Administration Office of Safety 

1200 New Jersey Ave., SE 

Washington, DC 20590 

13. Type of Report and Period

Technical Report / Informational Report

November 2018 to December 2019 

14. Sponsoring Agency Code

FHWA 

15. Supplementary Notes

Jeffrey Shaw (jeffrey.shaw@dot.gov), Office of Safety Technologies (http://safety.fhwa.dot.gov/), served as the Technical 

Manager for the Federal Highway Administration (FHWA). The following FHWA staff contributed as technical working group 

members, reviewers and/or provided input or feedback to the project at various stages: Dr. Wei Zhang, Mark Doctor, Tim Taylor, 

Dave Petrucci and Dr. Hillary Isebrands. Dr. Joseph Hummer (jehummer@ncdot.org), North Carolina Department of 

Transportation (NCDOT) State Traffic Management Engineer, served as Document Technical Manager. The following NCDOT 

staff contributed as technical working group members, reviewers, and/or provided input or feedback to the project at various 

stages: Jason Moore, Jason Galloway, Hanna Cockburn, and Renee Roach. Other contributors included: Brian Fowler, City of 

Norfolk, VA. 

16. Abstract

This document provides information and guidance on Quadrant Roadway (QR) intersections, resulting in designs suitable for a 

variety of typical conditions commonly found in the U.S. To the extent possible, the guide addresses a variety of conditions found 

in the U.S., to achieve designs suitable for a wide array of potential users. This guide provides general information, planning 

techniques, evaluation procedures for assessing safety and operational performance, design guidelines, and principles to be 

considered for selecting, planning, designing, and implementing QR intersections. 

17. Key Words

QR Intersection, Quadrant Roadway, Quadrant Left, Alternative Intersection, 

Innovative Intersection, Reduced Conflict Intersection 

18. Distribution Statement

No restrictions. 

19. Security Classif. (of this report)

Unclassified 

20. Security Classif. (of this page)

Unclassified 

21. No. of Pages

180

22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed pages authorized 
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TABLE OF CONTENTS 

CHAPTER 1 — INTRODUCTION............................................................................................ 1

OVERVIEW OF ALTERNATIVE INTERSECTIONS AND INTERCHANGES ................... 1

INTERSECTION CONTROL EVALUATIONS AND CONSIDERATIONS ......................... 1

ORGANIZATION OF THE GUIDE .......................................................................................... 2

SCOPE OF THE GUIDE ............................................................................................................ 3

QUADRANT ROADWAY INTERSECTION OVERVIEW .................................................... 3

QUADRANT ROADWAY APPLICATIONS ........................................................................... 6

GEOMETRIC DESIGN CONSIDERATIONS .......................................................................... 9

RESOURCE DOCUMENTS .................................................................................................... 21

CHAPTER 2 — POLICY AND PLANNING .......................................................................... 23

PLANNING CONSIDERATIONS FOR ALTERNATIVE INTERSECTIONS ..................... 23

STAKEHOLDER OUTREACH ............................................................................................... 27

POLICY CONSIDERATIONS ................................................................................................ 30

PLANNING CONSIDERATIONS .......................................................................................... 31

PLANNING CHALLENGES ................................................................................................... 31

PROJECT PERFORMANCE CONSIDERATIONS ............................................................... 32

PROJECT DEVELOPMENT PROCESS ................................................................................. 33

SUMMARY OF QR INTERSECTION ADVANTAGES AND DISADVANTAGES ........... 34

CHAPTER 3 — MULTIMODAL CONSIDERATIONS........................................................ 37

DESIGN PRINCIPLES AND APPROACH ............................................................................ 37

PEDESTRIANS ........................................................................................................................ 39

BICYCLISTS ............................................................................................................................ 45

TRANSIT VEHICLE CONSIDERATION .............................................................................. 51

HEAVY VEHICLE CONSIDERATIONS ............................................................................... 53

CHAPTER 4 — SAFETY .......................................................................................................... 55

SAFETY PRINCIPLES ............................................................................................................ 55

SAFETY CONCERNS ............................................................................................................. 61

INCIDENT RESPONSE CONSIDERATIONS ....................................................................... 65

OBSERVED SAFETY PERFORMANCE ............................................................................... 65

SUMMARY OF SAFETY EVALUATION CONSIDERATIONS ......................................... 68

CHAPTER 5 — OPERATIONAL CHARACTERISTICS .................................................... 69

OPERATIONAL CONSIDERATIONS ................................................................................... 70

SIGNAL CYCLE LENGTHS, PHASING AND COORDINATION ...................................... 79
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THROUGHPUT AND FLOW RATES.................................................................................... 84

COMPARATIVE PERFORMANCE STUDIES AND LITERATURE REVIEWS................ 85

CHAPTER 6 — OPERATIONAL ANALYSIS....................................................................... 93

OPERATIONAL ANALYSIS TOOL OVERVIEW................................................................ 94

PLANNING-LEVEL ANALYSIS ........................................................................................... 96

HIGHWAY CAPACITY ANALYSIS ANALYSIS .............................................................. 100

MICROSIMULATION ANALYSIS...................................................................................... 104

SUMMARY............................................................................................................................ 105

CHAPTER 7 — GEOMETRIC DESIGN .............................................................................. 107

DESIGN APPROACH ........................................................................................................... 107

GEOMETRIC DESIGN PRINCIPLES.................................................................................. 108

GEOMETRIC DESIGN PARAMETERS.............................................................................. 108

OPERATIONAL EFFECTS OF GEOMETRIC DESIGN..................................................... 113

DESIGN GUIDANCE............................................................................................................ 120

CHAPTER 8 — SIGNAL, MARKING, SIGNS, AND LIGHTING CONSIDERATIONS123

DESIGN PRINCIPLES AND APPROACH .......................................................................... 123

SIGNALS................................................................................................................................ 123

SIGNING................................................................................................................................ 128

PAVEMENT MARKING....................................................................................................... 136

CHAPTER 9 — CONSTRUCTION AND MAINTENANCE.............................................. 137

CONSTRUCTION.................................................................................................................. 137

COSTS .................................................................................................................................... 139

MAINTENANCE ................................................................................................................... 140

LAW ENFORCEMENT......................................................................................................... 143

APPENDIX A – CATALOG OF KNOWN INSTALLATIONS IN THE U.S. ................... 145

Intersection Profile 1: SR-4 at SR-4 bypass, Fairfield, OH .................................................... 146

Intersection Profile 2: NC-73 at US-21, Huntersville, NC ..................................................... 148

Intersection Profile 3: US-340/522 at SR-55, Front Royal, VA ............................................. 150

Intersection Profile 4: US-42 at KY-872, Florence, KY ........................................................ 152

Intersection Profile 5: US-220 at Church St, Greensboro, NC ............................................... 153

Intersection Profile 6: Market St at Kerr Ave, Wilmington, NC............................................ 154

APPENDIX B – MARKETING / OUTREACH MATERIALS ........................................... 157

APPENDIX C – ARTICLES, PAPERS, AND PUBLICATIONS........................................ 161

ACKNOWLEDGEMENTS ..................................................................................................... 163

REFERENCES.......................................................................................................................... 165
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LIST OF FIGURES 

Figure 1. Graphic. Key characteristics of a QR intersection. ......................................................... 3

Figure 2. Graphic. QR intersection left-turn patterns from D Street. ............................................. 4

Figure 3. Graphic. QR intersection left-turn patterns from A Street. ............................................. 4

Figure 4. Graphic. Locations of QR intersections in the U.S. ........................................................ 6

Figure 5. Photo. SR-4 / SR-4 Bypass QR intersection, Fairfield, Ohio. ......................................... 7

Figure 6. Photo. NC-73 / US-21 Partial QR intersection, Huntersville, North Carolina.(2)............ 7

Figure 7. Photo. US-340/522 / SR-55 QR intersection, Front Royal, Virginia. Provided by 

Virginia Department of Transportation. ......................................................................................... 8

Figure 8. Photo. US-42 / KY-872 QR intersection, Florence, Kentucky. ...................................... 8

Figure 9. Graphic. QR intersection evolution: initial quadrant roadway. ..................................... 10

Figure 10. Graphic. QR intersection evolution: coordinated signal operations. ........................... 11

Figure 11. Graphic. QR intersection evolution: final configuration. ............................................ 11

Figure 12. Graphic. Rendering of QR in urban area. .................................................................... 12

Figure 13. Graphic. Conventional intersection with double left-turn lanes. ................................. 13

Figure 14. Graphic. QR intersection facilitation of Complete Street development...................... 13

Figure 15. Graphic. QR intersection with secondary T-intersection roundabout. ........................ 15

Figure 16. Photo. QR intersection with access to inscribed land uses.......................................... 15

Figure 17. Photo. Imbalanced lanes on partial QR intersection. .................................................. 16

Figure 18. Photo. Dual Quadrant intersection (Bend, Oregon).(4)................................................ 17

Figure 19. Photo. Four-Quadrant intersection (Alpharetta, Georgia).(5)....................................... 18

Figure 20. Photo. Grade-separated QR intersection (Owens Mill, Maryland).(6)......................... 19

Figure 21. Photo. Hybrid QR / Median U-Turn (Bloomfield Hills, Michigan).(7)....................... 20

Figure 22. Graphic. Relationship between traffic volume served and intersection type. ............. 25

Figure 23. Graphic. QR intersection footprint compared to a conventional intersection. ............ 26

Figure 24. Graphic. Screenshot from video describing movement paths for QR project. ............ 28

Figure 25. Graphic. Screenshot from QR intersection informational video. Provided by Virginia 

Department of Transportation. ...................................................................................................... 28

Figure 26. Graphic. QR intersection microsimulation video. ....................................................... 29

Figure 27. Graphic. Enhanced project video using microsimulation data. ................................... 29

Figure 28. Graphic. Project development process. ....................................................................... 33

Figure 29. Graphic. Multimodal considerations. .......................................................................... 38

Figure 30. Graphic. Pedestrian-vehicle conflict points at a conventional intersection. ................ 40

Figure 31. Graphic. Pedestrian-vehicle conflict points at QR intersection. .................................. 40

Figure 32. Graphic. Pedestrian movements through a QR intersection. ....................................... 41
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Figure 33. Graphic. Conventional intersection crosswalk distances. ........................................... 42

Figure 34. Graphic. QR intersection crosswalk distances. ........................................................... 42

Figure 35. Graphic. Pedestrian walk phases at a conventional intersection. ................................ 43

Figure 36. Graphic. Pedestrian walk phases at a QR intersection. ............................................... 43

Figure 37. Photo. Example of pedestrian wayfinding provision via curbing. .............................. 45

Figure 38. Photo. Bike lanes at Front Royal QR intersection. ...................................................... 46

Figure 39. Graphic. Right-turn lane with bicycle lane.................................................................. 46

Figure 40. Graphic. Bicycle two-stage crossing path. .................................................................. 47

Figure 41. Graphic. Bicycle in-pavement bike box. ..................................................................... 48

Figure 42. Graphic. D Street bicyclists left turns following quadrant roadway. .......................... 49

Figure 43. Graphic. A Street bicyclists left turns following quadrant roadway. .......................... 50

Figure 44. Graphic. Desirable QR intersection rail crossings. ..................................................... 51

Figure 45. Graphic. Less desirable QR intersection rail crossings. .............................................. 51

Figure 46. Graphic. Potential bus stop locations. ......................................................................... 53

Figure 47. Graphic. Vehicle-vehicle conflict points at conventional intersection. ....................... 56

Figure 48. Graphic. Vehicle-vehicle conflict points at QR intersection. ...................................... 57

Figure 49. Graphic. QR intersection MT-QL-QR pattern. ........................................................... 58

Figure 50. Graphic. QR intersection QL-QL pattern.................................................................... 58

Figure 51. Graphic. QR intersection QR-QL-MT pattern. ........................................................... 59

Figure 52. Graphic. QR intersection MT-QR-QR-MT pattern. .................................................... 59

Figure 53. Graphic. Hybrid QR intersection with U-turn at secondary T-intersection. ............... 61

Figure 54. Photo. Traffic camera capture of illegal turns at QR intersection. .............................. 62

Figure 55. Equation. Calculation of safe stopping distance. ......................................................... 62

Figure 56. Graphic. QR intersection braking distances. ............................................................... 63

Figure 57. Graphic. Queue storage areas of concern. ................................................................... 64

Figure 58. Graphic. Conventional versus QR left turn movements: D Street. ............................. 69

Figure 59. Graphic. Conventional versus QR left turn: A Street. ................................................. 69

Figure 60. Graphic. QR intersection access impacts. ................................................................... 71

Figure 61. Graphic. QR RIRO access management recommendations. ....................................... 73

Figure 62. Graphic. QR directional access management recommendations. ............................... 73

Figure 63. Graphic. Directional vehicle paths w/RIRO access on quadrant roadway. ................. 74

Figure 64. Graphic. Directional vehicle paths w/directional access on quadrant roadway. ......... 75

Figure 65. Graphic. Additional QR left-turn travel distances at 500-ft spacing. .......................... 76

Figure 66. Graphic. Additional QR left-turn travel distances at 800-ft spacing. .......................... 76
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Figure 67. Graphic. 150-second conventional intersection multi-phase signal splits................... 79

Figure 68. Graphic. 90-second QR main intersection signal splits............................................... 80

Figure 69. Graphic. 90-second QR secondary-T intersection signal splits................................... 80

Figure 70. Chart. Comparison of movement green times. ............................................................ 81

Figure 71. Graphic. QR intersection signal phasing. .................................................................... 82

Figure 72. Graphic. QR intersection time-space diagram............................................................. 83

Figure 73. Graphic. Lane continuity through QR left-turn movement......................................... 85

Figure 74. Graphic. Throughput comparison of QR versus conventional intersection. ............... 90

Figure 75. Graphic. Translating turn movements from conventional to a QR intersection.......... 95

Figure 76. Graphic. Converting conventional to QR intersection volumes. ................................. 96

Figure 77. Graphic. CAP-X planning level tool screen capture for QR intersection. .................. 99

Figure 78. Graphic. HCM method for QR evaluation. ............................................................... 102

Figure 79. Graphic. QR intersection characteristics. .................................................................. 107

Figure 80. Graphic. QR intersection geometric design (DS=30mph). ....................................... 109

Figure 81. Graphic. QR intersection geometric design (DS=35mph). ....................................... 109

Figure 82. Graphic. Two-lane quadrant roadway. ...................................................................... 110

Figure 83. Graphic. Four-lane quadrant roadway. ...................................................................... 110

Figure 84. Graphic. Six-lane quadrant roadway. ........................................................................ 111

Figure 85. Photo. Use of parcel inside quadrant roadway for biorention pond. ......................... 113

Figure 86. Graphic. Preferred secondary T-intersection geometry............................................. 114

Figure 87. Graphic. Secondary T-intersection geometry to avoid.............................................. 114

Figure 88. Graphic. Secondary T-intersection compromise 1. ................................................... 115

Figure 89. Graphic. Secondary T-intersection compromise 2. ................................................... 115

Figure 90. Graphic. Secondary T-intersection compromise 3. ................................................... 116

Figure 91. Graphic. Secondary T-intersection compromise 4. ................................................... 116

Figure 92. Graphic. Huntersville QR intersection access lessons learned.................................. 117

Figure 93. Graphic. Preferred quadrants at skewed intersections............................................... 118

Figure 94. Graphic. Undesirable quadrants at skewed intersections. ......................................... 118

Figure 95. Graphic. Types of channelized turns (1).(21).............................................................. 119

Figure 96. Graphic. Types of channelized turns (2).(21).............................................................. 119

Figure 97. Graphic. Pedestrian crosswalk placements. ............................................................... 120

Figure 98. Graphic. Main intersection design guidance. ............................................................ 121

Figure 99. Graphic. Fairfield median lessons learned. ............................................................... 122

Figure 100. Graphic. Typical mast arm pole, signal head, and cabinet placement. ................... 124
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Figure 101. Graphic. Detector placements. ................................................................................ 127

Figure 102. Photo. QR intersection regulatory signing, Fairfield, Ohio. .................................... 129

Figure 103. Photo. QR intersection regulatory signing, Front Royal, Virginia. ......................... 129

Figure 104. Photo. QR intersection regulatory signing, Huntersville, North Carolina. ............. 129

Figure 105. Graphic. Typical QR intersection signing plan for juncture of two U.S. routes. .... 130

Figure 106. Graphic. Typical QR intersection signing plan for juncture of State/local route. ... 131

Figure 107. Graphic. QR intersection overhead signing plan for westbound NC-73. ................ 132

Figure 108. Graphic. QR intersection overhead signing plan for eastbound NC-73. ................. 132

Figure 109. Photo. Examples of QR overhead signing, Hunstersville, North Carolina. ............ 133

Figure 110. Photo. Examples of QR overhead signing, Front Royal, Virginia. ......................... 133

Figure 111. Photo. Examples of QR overhead signing, Fairfield, Ohio. .................................... 133

Figure 112. Photo. Route wayfinding signs on Front Royal quadrant roadway. ........................ 134

Figure 113. Photo. Services wayfinding signs on Huntersville quadrant roadway. ................... 134

Figure 114. Graphic. MUTCD signing for left-turn bike boxes.(10)............................................ 135

Figure 115. Photo. Local example of bike box signing. ............................................................. 135

Figure 116. Photo. Directional shield pavement marking, Huntersville, North Carolina. ......... 136

Figure 117. Photo. Directional shield pavement marking, Front Royal, Ohio. .......................... 136

Figure 118. Graphic. Front Royal construction maintenance of traffic lessons learned. Provided 

by Virginia Department of Transportation. ................................................................................ 142

Figure 119. Photo. SR-4 at SR-4 Bypass, Fairfield, Ohio. ......................................................... 146

Figure 120. Photo. NC-73 at US-21, Huntersville, North Carolina. ........................................... 148

Figure 121. Photo. US-340/522 at SR-55, Front Royal, Virginia. Provided by Virginia 

Department of Transportation..................................................................................................... 150

Figure 122. Photo. US-42 at KY-872, Florence, Kentucky........................................................ 152

Figure 123. Photo. US-220 at Church St. Greensboro, North Carolina. ..................................... 153

Figure 124. Photo. Market Street at Kerr Avenue, Wilmington, North Carolina. ...................... 155

Figure 125. Graphic. FHWA innovative intersection (RCUT) video. ........................................ 157

Figure 126. Graphic. FHWA innovative intersection informational drive-through video. ........ 157

Figure 127. Graphic. Example of QR intersection video developed for Front Royal project. ... 158

Figure 128. Graphic. Example of QR intersection video developed for Huntersville project.... 158
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LIST OF TABLES

Table 1. Comparison of QR intersection. ....................................................................................... 9

Table 2. Alternative intersection and interchange types used in the U.S. .................................... 24

Table 3. Summary of QR intersection advantages and disadvantages. ........................................ 35

Table 4. Conflict point comparison. ............................................................................................. 57

Table 5. Minimum intersection spacing by stopping sight distance. ............................................ 63

Table 6. Three-year crash data comparison at Fairfield QR intersection. .................................... 66

Table 7. Three-year crash data comparison at Huntersville QR intersection. .............................. 67

Table 8. One-year crash data comparison at Front Royal QR intersection. ................................. 67

Table 9. Additional QR left-turn travel distances: Street C-D spacing = 400 ft. .......................... 77

Table 10. Additional QR left-turn travel distances: Street C-D spacing = 500 ft. ........................ 77

Table 11. Additional QR left-turn travel distances: Street C-D spacing = 600 ft. ........................ 77

Table 12. Additional QR left-turn travel distances: Street C-D spacing = 700 ft. ........................ 77

Table 13. Additional QR left-turn travel distances: Street C-D spacing = 800 ft. ........................ 77

Table 14. Storage bay and taper length guidance. ........................................................................ 78

Table 15. Summary of comparison literature and performance studies. ...................................... 86

Table 16. Summary of ITE study results. ..................................................................................... 87

Table 17. TRB study intersection evaluated. ................................................................................ 88

Table 18. Summary of TRB study results.(27) ............................................................................... 89

Table 19. QR intersection analysis techniques. ............................................................................ 94

Table 20. V/C correlation to LOS. ................................................................................................ 97

Table 21. CLV capacity by number of signal phases. .................................................................. 97

Table 22. Conventional and QR intersection critical lane capacity analysis. ............................... 98

Table 23. LOS criteria for signalized intersections.(9) ................................................................ 101

Table 24. Input data for HCM evaluation of QR. ....................................................................... 103

Table 25. Best use of analysis tools............................................................................................ 105

Table 26. Considerations for one versus three controllers at a QR intersection. ........................ 125

Table 27. Summary of costs associated with QR intersections. ................................................. 140

Table 28. Full, partial, and hybrid QR intersections in the U.S. ................................................. 145
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LIST OF ABBREVIATIONS 

AASHTO American Association of State Highway and Transportation Officials 

ACEC American Civil Engineering Council 

ADA Americans with Disabilities Act 

ADT average daily traffic 

AIIR Alternative Intersections and Interchanges Informational Report 

BRT bus rapid transit 

CAP-X Capacity Analysis for Planning of Junctions 

CL cycle length 

CLV critical lane volume 

DDI Diverging Diamond Interchange 

DLT Displaced Left Turn 

DS Design Speed 

EDC Every Day Counts 

FHWA Federal Highway Administration 

HCM Highway Capacity Manual 

HSM Highway Safety Manual 

ICE Intersection Control Evaluation 

ITE Institute of Transportation Engineers 

ITS Intelligent Transportation System 

KYTC Kentucky Transportation Cabinet 

LOS level-of-service 

LRT light rail transit 

MMLOS multimodal level-of-service 

MOEs measures of effectiveness 

MUT Median U-Turn 

MUTCD Manual on Uniform Traffic Control Devices 

NCDOT North Carolina Department of Transportation 

NCHRP National Cooperative Highway Research Program 

O-D origin-destination 

ODOT Ohio Department of Transportation 

OSOW over-size / over-weight 

PROWAG Public Rights-of-Way Accessibility Guidelines 

QR Quadrant Roadway

RCUT Restricted Crossing U-Turn 

RIRO right-in/right-out 

ROW right-of-way

RTOR right-turn-on-red

TRB Transportation Research Board 

TTST Tractor Trailer / Semi Truck 

V/C volume-to-capacity 

VDOT Virginia Department of Transportation 

VPHPL vehicles-per-hour-per-lane 

Y/AR yellow and all-red 
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QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

1

CHAPTER 1 — INTRODUCTION 

OVERVIEW OF ALTERNATIVE INTERSECTIONS AND INTERCHANGES 

Alternative intersections and interchanges offer the potential to improve safety and reduce delay 

at a lower cost and with fewer impacts than traditional solutions. However, transportation 

professionals may be unfamiliar with many alternative intersection and interchange forms, 

partially because some forms have only a few installations in operation or because installations 

are concentrated in a few States. Furthermore, at the national level, well-documented and 

substantive resources needed for planning, analysis, design, public outreach, and education have 

been limited. 

Previous to this Quadrant Roadway Informational Guide, the Federal Highway Administration 

(FHWA) developed and published informational guides in 2014 for four alternative intersection 

and interchange forms: the Median U-Turn (MUT), Displaced Left Turn (DLT), Restricted 

Crossing U-Turn (RCUT), and Diverging Diamond Interchange (DDI). The guides have 

increased awareness of these specific alternative intersections and provide guidance on how to 

plan, design, construct, and operate them. Collectively, these guides represent summaries of the 

current state of knowledge with the intent of supporting decisions when considering and 

potentially selecting alternative intersection and interchange forms for appropriate applications. 

INTERSECTION CONTROL EVALUATIONS AND CONSIDERATIONS 

The term “intersection” means the junction of two or more street facilities. In some cases, this 

may specifically mean an “at-grade” intersection form. In others, it may include the junction of 

two or more streets requiring partial or complete grade separation (“interchanges”). A number of 

State and local transportation agencies have or are implementing intersection control evaluation 

(ICE) processes and/or policies as a means of integrating the widest range of intersection forms 

as project solutions. 

Many ICE policies or processes include common objectives in selecting the optimal or preferred 

intersection control alternative for a given project context. The common elements generally 

include, but are not limited to, the following: 

• Understanding how operations, safety, and geometry fit the context for each intersection or 

corridor for intended users including pedestrians, bicyclists, passenger cars, transit vehicles, 

freight, emergency responders, and over size/over weight (OSOW) vehicles. 

• Identifying and documenting the overall corridor or intersection context including the built, 

natural, and community environment and the intended performance. 

• Considering and assessing a wide range of traffic control strategies and other practical 

improvement concepts to identify necessary project-level technical evaluation. 

• Comparing engineering and economic analysis results of practical alternatives that consider 

implementation costs, performance benefits and impacts (safety, multimodal, operations, 

environment, etc.), and the estimated service life of alternatives. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION

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ORGANIZATION OF THE GUIDE

This guide is structured to address the needs of a variety of readers, including the general public, 

policy makers, transportation planners, operations and safety analysts, and conceptual and 

detailed designers regarding quadrant roadway (QR) intersections. This section provides an 

overview of each chapter in this guide and distinguishes QR intersections from conventional 

intersections. The remaining chapters in this guide increase the level of detail provided. 

Chapter 2: Policy and Planning – This chapter provides guidance on when to consider 

alternative intersections in general and QR intersections in particular. Considerations related to 

policies, project challenges, performance measures, and the project development process 

throughout the duration of the project are presented.

Chapter 3: Multimodal Considerations – This chapter provides an overview of multimodal 

facilities at QR intersections and how the needs of various users should inform decisions to 

produce a facility that optimally serves motorized and non-motorized traffic.

Chapter 4: Safety – This chapter summarizes documented safety performance and safety 

considerations at QR intersections based on studies completed by State agencies and recent 

research efforts. Although the documented safety performance of QR intersections is limited, 

information about conflict points and emergency services at these intersections are discussed.

Chapter 5: Operational Characteristics – This chapter provides information on the unique 

operational characteristics of QR intersections and how they affect elements such as traffic signal 

phasing and coordination. The chapter also provides guidance for practitioners related to design 

elements such as the location of the quadrant roadway, access management, and intersection 

spacing that may affect the operational performance of QR intersections. It describes unique 

operational characteristics of QR intersections and prepares transportation professionals for 

conducting operational analysis as described in chapter 6.

Chapter 6: Operational Analysis – This chapter presents an overview of the approach and tools 

available for conducting a traffic operations analysis of a QR intersection. 

Chapter 7: Geometric Design – This chapter describes the typical QR intersection design 

approach and provides guidance for geometric features. Design of a QR intersection will also 

require reviewing and integrating the intersection’s multimodal considerations (chapter 3), safety 

assessment (chapter 4), and traffic operational analysis (chapters 5 and 6). 

Chapter 8: Signal, Signing, Marking, and Lighting – This chapter presents information 

relating to the design and placement of traffic control devices at QR intersections, including 

traffic signals, signs, pavement markings, and intersection lighting. 

Chapter 9: Construction and Maintenance – This chapter focuses on the constructability and 

maintenance of a QR intersection. 

An Appendix is included at the end of this guide for the purpose of providing more detailed 

information about many of the resources and best practices relating to QR intersections. The 

Appendix contains the following information:

A – Catalog of known installations in the U.S.

B – Marketing and outreach materials.

C – Articles, papers, and publications.
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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SCOPE OF THE GUIDE 

This document provides information and guidance on planning and designing QR intersections, 

resulting in designs suitable for a variety of conditions commonly found in the U.S. To the extent 

possible, the guide provides information on how QR intersections can accommodate a wide 

variety of users. Developed from best practices and prior research, the scope of this guide is to 

provide general information, planning techniques, evaluation procedures for assessing safety and 

operational performance, design guidelines, and principles to be considered for selecting and 

designing QR intersections. This guide does not include specific legal or policy requirements. 

However, chapter 2 provides information on planning topics and considerations when 

investigating new intersection control forms. This first edition of the Quadrant Roadway 

Informational Guide has been developed from documented practices and prior research. As more 

QR intersections are built, there will be further opportunities to conduct research to refine 

existing and develop new methods to inform project decisions about this intersection form. 

QUADRANT ROADWAY INTERSECTION OVERVIEW 

The QR intersection is also known as the “Quadrant”, “Quadrant Left”, or “Single Quadrant” 

intersection. For the purposes of this informational guide, a QR intersection refers to any atgrade intersection of two roadways where left turns are displaced to a quarter-arc “quadrant 

roadway” in one intersection quadrant. This quadrant roadway can be constructed new or an 

existing road can be repurposed. Figure 1 depicts key characteristics of a typical QR intersection. 

While the figure depicts a roadway in the southwest quadrant with three signalized intersections, 

the roadway can be effectively located in any intersection quadrant, and while the main 

intersection is always signalized, the secondary T-intersections may or may not be signalized. 

 © NCDOT 

Figure 1. Graphic. Key characteristics of a QR intersection. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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Under the QR intersection, all left-turn movements typically made directly at the main 

intersection are now displaced and made indirectly using the quadrant roadway. Each indirect 

left-turn pattern is different as illustrated in figure 2 and figure 3 below, which depict the 

quadrant roadway in the southwest intersection quadrant. In these figures and throughout the 

guide, the street that provides the left turn onto the quadrant roadway in advance of the main 

intersection is called “A Street”, and the street that provides the left turn onto the quadrant 

roadway downstream of the main intersection is called “D Street”. Figure 2 illustrates the 

indirect left-turn patterns from D Street, which both use the quadrant in a counterclockwise 

direction. Figure 3 illustrates the indirect left-turn patterns from A Street, which both use the 

quadrant in a clockwise direction. 

 © NCDOT 

Figure 2. Graphic. QR intersection left-turn patterns from D Street. 

 © NCDOT 

Figure 3. Graphic. QR intersection left-turn patterns from A Street. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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Each QR left-turn movement depicted in figure 2 and figure 3 is described below:

1. Vehicles westbound on D Street wanting to turn left onto A Street first pass through the 

main intersection, turn left onto the quadrant roadway, and turn right onto A Street. 

2. Vehicles eastbound on D Street wanting to turn left onto A Street make a right turn onto the 

quadrant roadway in advance of the main intersection, turn left onto A Street, and pass 

northbound through the main intersection. 

3. Vehicles northbound on A Street wanting to turn left onto D Street first turn left onto the 

quadrant roadway in advance of the main intersection and turn left again at the end of the 

quadrant roadway onto D Street, bypassing the main intersection altogether. 

4. Vehicles southbound on A Street wanting to turn left onto D Street first pass through the 

main intersection, turn right onto the quadrant roadway, turn right again at the end of the 

quadrant roadway, and pass eastbound through the main intersection. 

By eliminating left turns on both roadways at the main intersection, the QR intersection reduces 

the number of traffic signal phases and conflict points at the main intersection, resulting in 

improved intersection operations. At typical QR intersections, the secondary T-intersections at 

each end of the quadrant roadway are spaced approximately 500 ft from the main intersection, 

and access is fully controlled along the entirety of the quadrant roadway (i.e., no intermediate 

access to adjacent land uses). 

History of the QR Intersection 

Intersection designs that reroute one or more left-turn movements using connecting roadways 

have been used in some parts of the U.S. for decades. However, the formalization of rerouting all 

left turn-movements using a standardizing QR intersection was first proposed and published by 

Reid and Hummer in the Institute of Transportation Engineers (ITE) Journal in June 2000.

(1) This 

version of a QR intersection was eventually planned and designed for NC-73 and US-21 in 

Huntersville, North Carolina, which opened in 2012. 

Independent of the work by Reid and Hummer, the Ohio Department of Transportation (ODOT) 

developed a “diversion road” concept for the intersection of SR-4 / SR-4 Bypass in Fairfield, 

Ohio. The intersection design was a part of a larger SR-4 corridor improvement project that 

included RCUT (or superstreet) intersections. However, the superstreet concept could not 

adequately accommodate the balanced through volumes on both roadways at the SR-4 / SR-4 

Bypass intersection, and the availability of land in one intersection quadrant gave ODOT the 

opportunity to develop the diversion road concept. Interestingly, ODOT only learned about the 

QR intersection research after the SR-4 project went to construction, though some of the research 

was helpful during the project media rollout phase. The SR-4 / SR-4 Bypass project opened in 

January 2012, making it the first QR intersection to open in the U.S. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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QUADRANT ROADWAY APPLICATIONS 

Though an emerging alternative intersection form, several QR and hybrid-QR intersections have 

been constructed throughout the U.S. Figure 4 shows the location of known QR, hybrid and 

partial QR, and multiple quadrant QR intersections in operation or under construction as of the 

publication of this guide. These intersections are also catalogued in Appendix A. 

Figure 4 through figure 8 feature photos of the four most recent QR intersections open or 

currently under construction in the U.S. These intersection locations include:

• SR-4 at SR-4 Bypass, Fairfield, Ohio (suburb of Cincinnati); opened January 2012. 

• US-21 at NC-73, Huntersville, North Carolina (suburb of Charlotte); opened March 2012.

• US-340/522 at SR-55, Front Royal, Virginia; opened December 2017. 

• US-42 at KY-872, Florence, Kentucky; opened August 2019. 

Source: FHWA 

Figure 4. Graphic. Locations of QR intersections in the U.S. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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© ODOT 

Figure 5. Photo. SR-4 / SR-4 Bypass QR intersection, Fairfield, Ohio.

© 2019 Google Earth® 

Figure 6. Photo. NC-73 / US-21 Partial QR intersection, Huntersville, North Carolina.

(2)
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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© Virginia Department of Transportation. 

Figure 7. Photo. US-340/522 / SR-55 QR intersection, Front Royal, Virginia. Provided by 

Virginia Department of Transportation. 

© KYTC

Figure 8. Photo. US-42 / KY-872 QR intersection, Florence, Kentucky.
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION

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Table 1 compares the different design, contextual, and built environments for the four most 

recent QR intersections built or under construction. Elements of each of these intersections are 

detailed throughout the guide and a profile of each intersection is included in Appendix A.

Table 1. Comparison of QR intersection. 

Criteria

SR-4 at SR-4 Byp 

Fairfield, OH

US-21 at NC-73 

Huntersville, NC

US-340 at SR-55 

Front Royal, VA

US-42 at KY-872

Florence, KY

Quadrant Roadway Constructed new Repurposed 

existing roadway Constructed new Constructed new

Main Crossing

Intersection Full QR Partial QR Full QR Full QR

Secondary TIntersectionBoth Tintersections

Both intersections 

have 4th leg (1 full 

access, 1 partial)

Both Tintersections w/

access control

Both Tintersections

Avg. Daily Traffic

(ADT) Volumes

Year: 2011

SR-4: 40,500

SR-4 Byp: 19,200

Year: 2016

NC-73: 44,000

US-21: 22,000 

Year: 2017

US-340: 18,000

SR-55: 4,000

Year: 2016

US-42: 37,500

KY-872: 15,600

Lanes on quadrant 

roadway 6 3 5 3

Area Inscribed by 

QR Vacant Retail / commercial developments Vacant Retail / commercial developments

Pedestrian / Bicycle 

Accommodations None Sidewalks on all roadways

Sidewalks on all 

approaches; Bike 

lane on US-340

Sidewalks on all 

roadways

Access on QR No access to 

adjacent land uses

Median break & 

RIRO access to 

adjacent land uses

No access to 

adjacent land uses

RIRO access to 

adjacent land uses 

& 1 full-access pt.

Medians on QR None Raised median; one 

directional opening Raised median None

GEOMETRIC DESIGN CONSIDERATIONS

Unlike many other alternative intersections, the QR has few unique design prescriptions other 

than the signature roadway in one intersection quadrant that facilitates the redirection of all left 

turns. A QR intersection design is influenced by the availability of land in one or more 

intersection quadrants and the spacing of existing roadways, intersections, and driveways along 

both intersecting roadways. The quadrant roadway can be built as a new roadway or developed 

by repurposing an existing roadway to function as the quadrant roadway, often requiring 

roadway and intersection geometric and signalization improvements.

Planning and design decisions are highly influenced by right-of-way (ROW) limits and 

availability on both crossing roadways and in the intersection quadrant(s), existing and future 

land use, access needs in the area inscribed by the quadrant roadway, intersection spacing,

bicycle and pedestrian volumes, and traffic demands. The quadrant roadway can have a varying 

number of through and turning lanes depending on current and projected intersection left-turn

volumes, land uses bisected by and adjacent to the quadrant roadway, and existing or planned 

future access to the quadrant roadway. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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Quadrant Roadway Flexibility 

The QR intersection is one of few alternative intersection forms that can be built effectively in 

any urban, suburban, and rural environment. In rural areas, undeveloped land parcels in one or 

more intersection quadrants in which to plan and construct a quadrant roadway are often more 

readily available. At intersections of foreseen future significance, the QR intersection footprint 

can be preserved when new land uses first emerge, and the quadrant roadway can evolve over 

time as traffic builds, as illustrated in figure 9 through figure 11.

Figure 9 illustrates a roadway constructed in one quadrant of an intersection on a strategically 

important State or municipal roadway network at a time when one or more quadrants are 

undeveloped. As traffic volume levels permit, the secondary T-intersections can operate under 

minor-street stop conditions. Direct left turns are permitted at the main intersection. 

 © NCDOT 

Figure 9. Graphic. QR intersection evolution: initial quadrant roadway.

As intersection congestion grows due to increased development and traffic volumes and/or safety 

issues arise at one (or both) secondary T-intersections, these intersection(s) can be signalized. 

The secondary T-intersection signals can be coordinated with the main intersection still running 

multi-phase signal operations. Figure 10 illustrates the QR intersection with coordinated, 

signalized secondary T-intersections, still with direct left turns at the main intersection. 

When intersection traffic volumes increase to cause an unacceptable level of operations, the full 

QR intersection can be implemented, as illustrated in figure 11. Construction activities to make 

the conversion include eliminating the left-turn bays on both intersecting roadways, revising 

signal and pedestrian heads, and perhaps adding additional turn lanes on the quadrant roadway. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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 © NCDOT 

Figure 10. Graphic. QR intersection evolution: coordinated signal operations. 

 © NCDOT 

Figure 11. Graphic. QR intersection evolution: final configuration. 

Under this planned conversion scenario, the motoring public would have to be informed and new 

habits formed during each intersection operational change. Also, there is a risk that the initial 

decision for an ultimate QR intersection made by one governing agency may not be advanced by 

future governing agencies. Close coordination with local governments and transportation 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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planning organizations is key to a successful phased approach, and all stakeholders need to be 

kept aware of the planned evolution. 

Where greenfield development of a quadrant roadway is not available, and no roadway is 

suitable for conversion to a quadrant roadway, community planners may consider redevelopment 

of an intersection quadrant when rezoning opportunities present themselves. Site redevelopment 

plans that include a quadrant roadway may improve access to commercial redevelopment by the 

improved accessibility and increased pass-by traffic the quadrant roadway affords to that 

quadrant. 

Quadrant Roadways in Urban Environments 

There are many opportunities for QR intersections in urban areas across the U.S. that can 

improve congested intersections in urban areas by reducing signal phases, providing greater 

multimodal opportunities and providing "back roadway” access to serve development. Figure 12

illustrates a QR concept for an urban area. 

© Metro Analytics 

Figure 12. Graphic. Rendering of QR in urban area. 

Many downtown or other urbanized areas are looking to implement Complete Streets, including 

broader pedestrian, bicycle, and transit amenities. The QR intersection may be a means to add 

space for these amenities by the removal of center turn lanes. The quadrant roadway may be 

developed using new or existing streets within the block-spacing of city streets. Eliminating leftturn lanes at the main intersection can open anywhere from 8 to 16 ft of ROW along the outside 

lanes that can be repurposed for wider sidewalks, a bikeway, a multi-use trail, or other complete 

street amenities. A well-planned QR intersection makes it possible for vehicles to access 

buildings via the quadrant roadway, so driveways can be removed (or not built) on both 

intersecting roadways. Used in urban settings, the QR main intersection operating under a twophase signal becomes much easier to coordinate with other signals in an urban street grid 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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network. Through movements on both roadways can support additional traffic with less delay,

reduced queuing, and lowered speed limits without degrading average speeds. QR intersections 

also make it easier and safer for pedestrians to cross at the main intersection, as described in 

greater detail in chapter 3. 

Figure 13 and figure 14 illustrate a before/after cross-sectional illustration of how a QR can 

facilitate a Complete Streets development. According to best practices from ITE, the crosssection elements in figure 13 are inappropriate for aspiring walkable mixed-use environments 

that a community may desire at major intersections (i.e., 12-ft lanes are too wide, and a 45-mph 

speed limit is too fast for the desired environment).(3) The redesigned QR intersection cross 

section in figure 14 includes narrower lanes and traffic calming features effective in reducing 

maximum speeds, which greatly improves safety. In addition, conversion to fewer signal phases 

afforded by the QR intersection can result in a more consistent peak-period experience despite 

the lower speed limit, for a “drive slower, travel faster” effect. 

© Metro Analytics 

Figure 13. Graphic. Conventional intersection with double left-turn lanes.

© Metro Analytics 

Figure 14. Graphic. QR intersection facilitation of Complete Street development. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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QR Intersection as an Interim Step to Grade Separation 

QR intersections can also serve as an intermediate stage between a conventional intersection and 

interchange. In this case, it is very important to emphasize planning, designing, and reserving 

ROW for the entire future interchange condition, not just the at-grade QR intersection. 

Otherwise, development will occur around the QR and intersection in the interim, negating the 

ability to construct the future interchange. Early in the development of a QR intersection, the 

governing highway agency may operate the intersection with conventional signalization, while 

acquiring and/or reserving ROW in one quadrant for future construction of a QR intersection. 

When demands are high enough to justify, the agency could build the quadrant roadway and 

operate the intersection as a QR intersection. In this intermediate stage, the QR intersection 

provides the benefit of efficient operations without the expense of constructing an interchange. If 

and when traffic demand exceeds the capacity of the at-grade QR intersection, the governing 

agency can build a grade-separated quadrant interchange, using the quadrant roadway as a 

staging roadway during the construction of the grade-separation of one roadway over the other or 

perhaps as part of the ramp system. 

Variations of the QR Intersection 

There are several design modifications that can be made to QR intersection to respond to specific 

operational, access, or area context needs, including: 

• One or both of the secondary T-intersections are roundabouts.

• Providing access to parcels bisected by, or adjacent to, the quadrant roadway.

• Redirecting left turns onto the QR from only one of the intersecting roadways (partial QR).

Secondary T-Intersection Roundabouts 

Figure 15 is a conceptual rendering of a QR intersection with a roundabout at one of the 

secondary T-intersections. Assuming a single or dual-lane roundabout can provide sufficient 

intersection capacity and does not induce queues that spill back to the main intersection, a 

roundabout intersection has two significant operational advantages: 1) the roundabout 

intersection simplifies the coordination of the two remaining signals, and 2) it allows a fourth leg 

to be added to the roundabout intersection without detrimental effects on traffic operations on 

either street or to overall QR intersection operations.

Access Provisions to Inscribed Quadrant

Figure 16 illustrates a QR intersection where land uses are inscribed within the quadrant 

roadway. These land uses have access directly onto the quadrant roadway at a full-access 

intersection, as well as right-in/right-out (RIRO) access to both intersecting roadways. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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 © NCDOT 

Figure 15. Graphic. QR intersection with secondary T-intersection roundabout. 

 © KYTC

Figure 16. Photo. QR intersection with access to inscribed land uses.
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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Partial Quadrant Roadways 

As previously illustrated in figure 2 and figure 3, left turns from each intersecting roadway are 

served in differing directions on the quadrant roadway. At the partial QR intersection in 

Huntersville, NC, left turns from NC-73 are made indirectly using the quadrant roadway in a 

counterclockwise direction, while direct left turns are allowed from US-21 at the main 

intersection. This creates an imbalanced demand for lanes on the quadrant roadway. Figure 17

illustrates the NC-73 / US-21 partial QR intersection, which includes a three-lane quadrant 

roadway, with two lanes in the counterclockwise direction to serve left turns from both directions 

on NC-73, and one lane in the clockwise direction to serve right turns and land uses with access 

to the quadrant roadway.

© Town of Huntersville NC

Figure 17. Photo. Imbalanced lanes on partial QR intersection. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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Other QR Intersection Forms 

While the scope of this guide focuses on the single-quadrant at-grade intersection form, there are 

other forms of intersections using quadrant roadways to relocate left turns that have been 

constructed in the U.S. These QR forms include: intersections with quadrant roadways in dual or 

all four quadrants, grade-separated quadrant intersections, and hybrids of a quadrant roadways 

with other alternative intersection forms. The following section describes and illustrates these 

quadrant intersection variations. These other quadrant intersection forms may be appropriate to 

consider when evaluating intersection improvement alternatives, but detailed investigations of 

these intersection forms are outside the scope of this guide. 

Dual-Quadrant Roadways 

Figure 18 illustrates quadrant roadways in two opposite quadrants (called a “Dual Quadrant” 

intersection). This alternative intersection simplifies both secondary T-intersections to allow twophase signal operations and movement paths that are more uniform to meet driver expectations; 

however, finding two opposite and suitable intersection quadrants can be challenging in built-up 

urban and suburban areas and bicycles and pedestrians have additional intersections to cross. 

© 2019 Google Earth® 

Figure 18. Photo. Dual Quadrant intersection (Bend, Oregon).(4) 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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Four-Quadrant Intersections 

Figure 19 illustrates quadrant roadways in all four intersection quadrants. Examples of fourquadrant intersections can be found in many communities in the U.S., but the added quadrant 

roadways are rarely used in conjunction with removal of left turns at the main intersection, 

including at this location. Therefore, the four-quadrant intersection (without redirecting left turns 

at the main intersection) helps local motorists familiar with left-turn “shortcuts” to avoid the 

main intersection, but overall main intersection operational gains are limited. 

© 2019 Google Earth® 

Figure 19. Photo. Four-Quadrant intersection (Alpharetta, Georgia).(5) 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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Grade-Separated QR Intersection 

There is also a grade-separated form of the QR intersection. Under this design, the secondary Tintersections operate the same way as described for the QR intersection but the two intersecting 

roadways are grade separated. Figure 20 illustrates a grade-separated quadrant intersection in an 

urban area. This grade-separated intersection form is fairly common in the U.S. and can be found 

in rural, suburban, and urban settings. This design further eliminates intersection conflict points 

and can provide significant capacity gains compared to the at-grade QR intersection, particularly 

when one or both roadways have high volumes. However, grade separating roadways can have 

negaitve impacts to roadway access (particlarily on the elevated roadway) and can divide 

communities if not planned and designed for cohesiveness. 

© 2019 Google Earth® 

Figure 20. Photo. Grade-separated QR intersection (Owens Mill, Maryland).(6) 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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Hybrid QR Intersection Forms 

Figure 21 illustrates the combination of a QR intersection with a median U-turn corridor in 

southeast Michigan. In this design, two left-turn movements are made using the QR roadway 

while the other two left turns are made using the median U-turn crossovers on the median 

divided major roadway. 

© 2019 Google Earth® 

Figure 21. Photo. Hybrid QR / Median U-Turn (Bloomfield Hills, Michigan).(7)
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 1: INTRODUCTION 

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RESOURCE DOCUMENTS 

This guide is supplemental to major resource documents including, but not limited to: 

• A Policy on Geometric Design of Highways and Streets (American Association of State 

Highway and Transportation Officials [AASHTO] Green Book).(8) 

• Highway Capacity Manual (HCM).(9) 

• Manual of Uniform Traffic Control Devices (MUTCD).(10) 

• FHWA Signalized Intersections: Informational Guide.(11) 

• Highway Safety Manual (HSM).(12) 

• Other referenced research documents that are more specialized to specific areas of the guide 

include various National Cooperative Highway Research Program (NCHRP) reports, 

Transportation Research Board (TRB) papers, Institute of Transportation Engineers (ITE) 

and FHWA publications.

The following are supplemental resource documents specific to QR intersections:

• ITE Journal (Vol 70 No 6, June 2000): Using Quadrant Roadways to Improve Arterial 

Intersection Operations.(1)

• FHWA Alternative Intersections and Interchanges: Informational Report (AIIR).(13) 

• FHWA Tech Brief on Quadrant Roadway Intersections (FHWA-HRT-09-058).(14) 

• TRB 5th Urban Street Symposium: An Update on the Quadrant Roadway Intersection.(15) 

QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 2: POLICY AND PLANNING

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CHAPTER 2 — POLICY AND PLANNING

This chapter contains guidance on how to consider alternative intersections in general and QR 

intersections in particular. It also summarizes policy and planning considerations related to QR 

intersections. The remaining chapters of this guide will provide specific details of the

multimodal, safety, operations, geometric design, and traffic control features of QR intersections.

Alternative intersections are often initially considered for operational or safety needs, and other 

key factors may include spatial requirements and multimodal needs. This chapter provides 

approximate footprints for different types of QR intersections to allow for planning-level 

screening and feasibility analysis. 

PLANNING CONSIDERATIONS FOR ALTERNATIVE INTERSECTIONS 

Alternative intersection evaluations may vary depending on the stage of the project development 

process. Each project stage can affect how the policy and technical considerations are assessed. 

While operation, design, safety, human factors, and signing controls should be considered at 

every stage of the development process, a planning-level design evaluation may not require the 

same level of analysis or detailed evaluation of each consideration as projects in later 

development stages. Evaluations should be as comprehensive as needed to answer key project 

questions for each unique project context. 

Specific planning level considerations that may make QR intersections an attractive alternative 

include improved pedestrian and bicycle quality of service, improved intersection operational 

efficiency, and a reduced footprint along the intersecting roadways.

Serving Pedestrians and Bicycles

When considering a QR intersection, integrating pedestrian and bicycle needs at an early stage of 

the project planning process yields a higher quality solution. The unique characteristics of a QR 

intersection typically reduce pedestrian crossing distances, vehicle/pedestrian conflict points, 

intersection cycle lengths (more cycles per hour), and the number of signal phases—all of which

result in benefits to pedestrians and bicyclists.

Pedestrians crossing through a QR intersection encounter fewer vehicular conflict points than at 

a conventional intersection; however, the QR intersection adds additional signalized intersections 

that some pedestrians must cross. At the main intersection, crosswalks can be placed across all 

intersection legs and generally follow direct corner-to-corner crosswalk paths similar to 

conventional intersections. Pedestrians cross one street during the opposite street through and 

right-turn signal phase and vice-versa.

Removing the left turns from the main intersection creates two-phase signal operations. This 

allows for a shorter signal cycle length while maintaining a similar green time for pedestrians 

and vehicles compared to a conventional intersection. This benefits pedestrians by creating more 

pedestrian phases per hour and less “don’t walk” time between “walk” phases (i.e., less wait time 

between walk signals). 

Complete Streets is a transportation policy and design approach requiring a street to be planned, 

designed, operated, and maintained to enable safe, convenient, and comfortable travel and access 

for users of all ages and abilities regardless of their mode of transportation. Even where built 

along principal or other high-volume streets designed to carry vehicles at higher speeds, QR 

intersections can be designed or retrofit to accommodate bicycle lanes. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 2: POLICY AND PLANNING 

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Most through and right-turning bicyclists navigate QR intersections in the same way as 

conventional intersections, with one right-turn movement having the option to use the quadrant 

roadway. Left-turning bicyclists have several options for navigating a QR intersection. Some 

movements can use the quadrant roadway and move with vehicular traffic. Others can pass 

through the intersection on a multi-use path as a pedestrian would. A third option is for bicyclists 

to make direct left turns and wait on the shoulder in bicycle lanes or bicycle boxes. 

While there are many opportunities for multimodal accommodations at a QR intersection, these 

design elements are not without challenges. Chapter 3 of this guide discusses challenges and 

considerations and provides recommendations for how to achieve safe and efficient provisions 

for multimodal users of QR intersections.

Improved Operations 

Alternative intersections have been well documented to improve intersection operations in many 

applications across the U.S. There are many different forms of alternative intersections and 

interchanges that vary in means but are similar in purpose to relocate left turns away from the 

main intersection. Table 2 lists the known alternative intersection, grade-separation, and 

interchange forms used in the U.S. Many have both signalized and unsignalized forms. 

Table 2. Alternative intersection and interchange types used in the U.S. 

Unsignalized 

Intersections 

Signalized 

Intersections

Grade-Separated 

Intersections

Interchanges

• High-T intersection 

• Mini, single, and multilane roundabouts 

• Offset-T intersection 

• RCUT / J-Turn 

intersection 

• RIRO w/downstream 

U-Turn 

• Bowtie 

• Continuous Flow 

• Continuous Green-T 

• Jughandle 

• Median U-Turn 

• Quadrant Roadway 

• RCUT (Superstreet) 

• Echelon 

• Single Quadrant 

• Displaced Left Turn 

• Diverging Diamond 

• Median Urban Diamond 

• Single Point Urban 

Diamond 

• Single, Dual, and Peanut 

roundabout interchanges 

The commonality of these alternative intersections is reduced conflict points, reduced signal 

phases, fewer clearance phases, and increased green time for through and right-turn movements, 

particularly for the roadway with dominant through movements. Fewer signal phases can allow 

shorter intersection cycle lengths resulting in more cycles per hour, further reducing vehicle 

delays and queuing. 

As part of ongoing efforts to improve the safety performance of all roads, FHWA encourages 

State Departments of Transportation (DOTs) to “consider alternative geometric intersection and 

interchange designs, which are specifically designed to reduce or alter conflict points, and allow 

for safer travel for motorists, pedestrians, and bicyclists. Past and ongoing FHWA studies of 

various alternative intersection and interchange designs implemented within the last few years 

document the magnitude of both safety and operational improvements”.

(16) 

Research in these and other documents finds that alternative intersections provide the greatest 

operational benefits compared to conventional intersection design at volume levels where 

conventional intersections begin to fail but do not justify grade separation. Many alternative 

intersections have delayed the construction or otherwise replaced projects to grade separate an 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 2: POLICY AND PLANNING 

25

intersection, providing sufficient at-grade intersection operations without the cost and access 

impacts of grade separation. Research also shows that alternative interchanges provide the 

greatest operational benefits at volume levels where conventional diamond or other conventional 

interchanges begin to fail but do not justify system interchange forms. 

Figure 22 conceptually depicts the relationship of conventional intersections, alternative 

intersections, and grade separations in their ability to serve increasing traffic volumes. Chapter 5 

documents the operational benefits of the QR alternative intersection compared to conventional 

intersection forms. 

QR intersections are best suited at intersections with balanced approach volumes (i.e., one 

roadway volume is not dominant over the other) and best competes with Median U-Turn and 

Continuous Flow intersections in a niche where two higher-demand streets meet. QR 

intersections do not compete with RCUT and other alternatives where the volumes on the two 

intersecting roadways are highly disproportionate, nor is it suited for intersections with less than 

four approaches. 

 Source: FHWA 

Figure 22. Graphic. Relationship between traffic volume served and intersection type. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 2: POLICY AND PLANNING 

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Reduced Roadway Footprint 

QR intersections generally have a smaller footprint along both intersecting roadways compared 

to a conventional intersection. Left-turn lanes are removed at the main intersection and the Tintersections typically require only a single left-turn lane, resulting in a narrower cross section 

compared to a conventional intersection with dual left-turn lanes. 

As an example, figure 23 illustrates a QR intersection footprint overlaid on the existing footprint 

at the meeting of two major roadways in Gwinnett County, Georgia. In this concept, the quadrant 

roadway requires a pavement area equaling 1.05 acres in a ROW of approximately 1.5 acres 

(excluding the area inscribed by the quadrant roadway); however, the pavement area saved along 

the two roadways is approximately 1.6 acres in a ROW of 1.8 acres (approximately 5.5 acres if 

the entire area inscribed by the quadrant roadway is included). In this case, the existing roadway 

pavement is not a savings (the pavement exists); however, this area could be repurposed for 

bicycle, pedestrian, or other Complete Streets purposes. 

 © NCDOT 

Figure 23. Graphic. QR intersection footprint compared to a conventional intersection. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 2: POLICY AND PLANNING

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The savings of ROW and/or pavement along the intersecting roadways makes the QR 

intersection a good choice for improvement at intersections with constrained ROW or close 

roadside development that would be impacted by traditional widening improvements. This 

additional space may be re-purposed for multimodal or other roadside improvements. Should 

future roadway improvements be required, one or both roadways can be widened to the outside, 

leaving the quadrant roadway configuration and median turn lanes unchanged. 

STAKEHOLDER OUTREACH

Stakeholder outreach is a critical part of any transportation project planning process, particularly 

when involving alternative intersections unfamiliar to the public and project stakeholders.

Successfully implementing the first QR intersection in a community may require targeted and 

proactive outreach and education to affected stakeholders and the general public. This would 

create opportunities to familiarize others with the potential benefits of QR intersections while 

creating opportunities to hear project-specific concerns and considerations to properly plan,

design, and construct a successful QR intersection.

Creating multiple forums to engage the public (including presentations at local council or board 

meetings, briefings at community organization functions, and project-specific open house 

meetings) results in opportunities to listen to community interests and share objective 

information about the intersection form. Media campaigns through local newspapers, television, 

informational videos, and public meetings can be effective methods of keeping the community 

informed. 

Videos are another helpful tool for public outreach and user education used by many agencies to 

demonstrate QR intersections. Some of the videos are developed through simulation tools; other

driver simulation videos help illustrate what drivers may expect when they travel through a QR 

intersection. Figure 24 and figure 25 are examples of video animation used to describe how to 

travel through a QR intersection. These video clips include narration that speak to the general 

public with a clear message of how a QR intersection functions for both a specific project and 

generic QR intersection, respectively. The video captured in figure 25 also highlights multimodal 

benefits of a QR intersection and can be found on the Virginia Department of Transportation 

(VDOT) innovative intersections website.

Videos can also be produced from many off-the-shelf microsimulation models used to analyze a 

specific project. These are very beneficial to the public to not only provide operational analysis 

results but to illustrate how the QR intersection functions and visually fits within the context of 

the intersection and community. Figure 26 illustrates a microsimulation model of a QR 

intersection used during the project planning stages to show proposed QR intersection traffic 

operations compared to conventional intersection improvements. Microsimulation data can also 

be exported into computer models for more realistic videos of intersection operations that bring 

in bicycle, pedestrian, and 3-D elements into the video, as illustrated in figure 27.

(17)
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© Town of Huntersville NC

Figure 24. Graphic. Screenshot from video describing movement paths for QR project. 

© Virginia Department of Transportation.

Figure 25. Graphic. Screenshot from QR intersection informational video. Provided by 

Virginia Department of Transportation. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 2: POLICY AND PLANNING 

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© NCDOT 

Figure 26. Graphic. QR intersection microsimulation video.

© Kittleson and Associates 

Figure 27. Graphic. Enhanced project video using microsimulation data.
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POLICY CONSIDERATIONS 

Designing, operating, and managing streets and intersections should align with the appropriate 

jurisdictional policies associated with that facility. The facility context, location, and type can 

often dictate the appropriateness of the ROW and access management needs associated with 

alternative intersections. The degree to which motor vehicle throughput should or should not be 

prioritized over other modes also plays a role in determining the appropriateness of alternative 

intersections at specific locations. 

Some of the policy considerations of a QR intersection include: 

• Access management policies and best practices. 

• Driveway and signal spacing criteria.

• Operational measures of effectiveness (MOEs) and criteria. 

• Pedestrian facilities and wayfinding for persons with disabilities, including requirements of 

the Americans with Disabilities Act (ADA) and Section 504 (the Rehabilitation Act).(18)

• Complete Streets policies or other provisions for safe and convenient pedestrian and bicycle 

facilities. 

• Design vehicle requirements. 

• Snow removal and storage.

• Incident management. 

• Emergency response needs. 

Access Management 

The subject of multiple and closely-spaced intersections, which can present challenges for 

movement progression and safety, has been one of the biggest concerns noted by practitioners 

involved in planning, building, and operating QR intersections, as well as by researchers who 

study the effects of QR intersection operations and safety. This section discusses how QR 

intersections differ from conventional intersections, and the specific access management issues 

relative to the QR intersection. Of equal importance to the management of traffic and 

progression through the multiple intersections is the preservation of only three legs of 

approaches at the secondary T-intersections. The operational and management impacts of 

allowing a fourth leg at either secondary T-intersection is described in greater detail in chapters 4 

and 5. 

Transportation agencies considering QR intersections where existing access points conflict with 

the secondary T-intersection location(s) may need to make access modifications or potentially 

trade the operational and safety benefits of controlled T-intersections in order to move the project 

forward. In some cases, QR intersections with compromised access management or even a 

partial QR intersection will operate better than conventional intersection improvements. Planners 

and designers should approach all QR projects with the intent of managing access required to 

operate a “pure” QR intersection; however, there may be access issues that, if left unresolved, 

may cause a QR intersection alternative to be dismissed. In such cases, engineers and decisionmakers must weigh the operational and safety trade-offs associated with access management 

desires verses improvement project needs on a project-by-project basis. 
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PLANNING CONSIDERATIONS 

The following are planning considerations for alternative intersection design: 

• Community goals – Outside formalized land use policies, cities, and communities often 

have general goals that provide insights about the nature and character of their community. 

These goals can range from concepts that preserve a historic character or identified heritage 

to creating walkable communities or Complete Streets. Other goals can be to encourage 

economic development by preserving existing business or residential areas while 

encouraging thoughtful development or redevelopment. Regardless of the specific goals or 

vision, these considerations may influence street and intersection design. 

• Surrounding land uses and zoning – Consider land uses surrounding the intersection and 

possible design modifications that can be made to improve land use and access viability. 

• Project context – Questions to identify stakeholders for a particular project may include: 

o What is the purpose and function of the existing or planned street facilities? 

o What existing and planned land uses are adjacent to or linked to the street facilities? 

o Who will likely use the street facilities given the existing and planned land uses? 

o What are the existing and anticipated future socio-demographic characteristics of the 

populations adjacent to or linked to the existing or planned street facilities? 

o What are the perceived or actual shortcomings of the existing street facilities? 

o Who has jurisdiction over the facility? 

o Where is capital funding for the project originating (or expected to originate)? 

o Who will operate and maintain the facility? 

• Multimodal considerations – As with any street segment or intersection, each 

configuration must consider and serve the various users who currently or may be expected 

to use the facilities. This includes pedestrians, bicyclists, and transit riders and can also 

include users with special needs such as the visually impaired, elderly, or young users. 

• Access management – Consideration of which existing or planned roadway access points 

may need modifications or stringent controls to ensure optimal intersection operations.

• Design vehicles – The intersection geometry will need to accommodate transit, emergency 

vehicles, freight, and potentially OSOW vehicles.

• Intersection roadway volumes – The QR intersection is best suited for intersections where 

the volumes on both crossing roadways are generally similar in magnitude. If one roadway 

has disproportionately higher volumes than the other, the secondary T-intersection on the 

dominant roadway may not be able to provide adequate capacity for the overall QR 

intersection to work properly.

PLANNING CHALLENGES 

Careful planning and addressing unique challenges pertaining to this alternative intersection 

form are a prerequisite for successful implementation of a QR intersection project. The following 

are some common challenges associated with planning QR intersections:

• Driver education – Successful implementations of alternative intersections are often 

preceded by public outreach and educational campaigns, which are typically not conducted 

for conventional intersection improvements. At QR intersections, the prohibition of left 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 2: POLICY AND PLANNING 

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turns at the main intersection and the use of the quadrant roadway for left turns should be 

communicated to the public prior to opening the intersection.

• Driver expectation – QR intersections have a differing left-turn pattern from each 

approach, some requiring counterintuitive movements from the right side of the street not 

meeting driver expectations. These left-turn paths must be clearly communicated in the 

intersection planning and design phases, particularly in signing and marking plans.

• Multimodal – As with most street or intersection improvements, QR intersections must 

consider and serve the various users who currently or may be expected to use the facilities. 

This should include pedestrians and bicycles, understanding that the exact provisions may 

necessarily vary from site to site. QR intersections should generally be compatible with 

transit services as well. 

• Sufficient quadrant ROW – The greatest challenge for the QR intersection is the 

provision of sufficient ROW to accommodate the quadrant roadway in a location that 

allows proper function of the intersection. Spacing of the secondary T-intersections too 

close or too far from the main intersection will result in operational inefficiency and lower 

the public perception of the QR intersection as an effective intersection solution. 

• Roadway network – Drivers may seek alternatives to QR intersection left-turn movements 

if they perceive a travel-time gain using adjacent roadway or parking-lot “cut-throughs”.

The potential becomes greater when there is a fourth leg at one or both secondary Tintersections. Care should be taken in the project planning and design phases to eliminate 

paths to circumvent QR lefts (or make as difficult and time-consuming as possible). 

PROJECT PERFORMANCE CONSIDERATIONS 

Measuring the effectiveness of overall project performance depends on the nature or catalyst for 

the project. Understanding the intended specific operational, safety, and geometric performance 

context for each intersection or corridor, including intended users, can help determine projectspecific performance measures. The project performance may be directly linked to the specific 

design choices and performance of the alternatives considered. The project performance 

categories described below can influence and are influenced by specific QR intersection design 

elements and their characteristics.

Accessibility 

Chapter 3 of this guide describes accessibility as it relates to special consideration given to 

pedestrians with disabilities including accommodating pedestrians with vision or mobility 

impairments. However, for the purposes of considering a project’s general context and the 

performance considerations, the term “accessibility” goes beyond the conversation of policy 

related to ADA and Public Rights-of-Way Accessibility Guidelines (PROWAG) and is meant to 

be considered in broader terms.(19) With respect to considering applicable intersection forms for a 

given project context, accessibility is defined broadly as the ability to approach a desired 

destination or potential opportunity for activity using highways and streets (including the 

sidewalks and/or bicycle lanes provided within those ROWs). This could include the ability for a 

large design vehicle to navigate an intersection as much as it might pertain to the application of 

snow mobiles or equestrian uses in some environments or conditions. 
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Mobility 

Mobility is defined as the ability to move various users efficiently from one place to another 

using highways and streets. Mobility can sometimes be associated with motorized vehicular 

movement and capacity. For the purposes of this guide, mobility is meant to be independent of 

any particular travel mode. 

Quality of Service 

Quality of service is defined as the perceived quality of travel by any roadway user. It is used in 

the HCM 6

th Edition to assess multimodal level of service (MMLOS) for motorists, pedestrians, 

bicyclists, and transit riders.(9) Quality of service may also include the perceived quality of travel 

by design vehicle users such as truck or bus drivers. 

Reliability 

Reliability is defined as the consistency of performance over a series of time periods (e.g., hourto-hour, day-to-day, year-to-year). 

Safety 

Safety is defined as the expected frequency and severity of crashes occurring on highways and 

streets. Expected crash frequencies and severities are often disaggregated by type, including 

whether or not a crash involves a non-motorized user or a specific vehicle type (e.g., heavy 

vehicle, transit vehicle, motorcycle). In cases where certain crash types or severities are small in 

number, as is often the case with crashes involving pedestrians or bicycles, it may be necessary 

to review a longer period of time to gain a more accurate understanding.

PROJECT DEVELOPMENT PROCESS 

For the purposes of this report, the project development process is defined as consisting of the 

stages described below. Federal, State, and local agencies may have different names or other 

nomenclature with the overall intent of advancing from planning to implementation. Figure 28

illustrates the overall project development process.

Source: FHWA 

Figure 28. Graphic. Project development process.

Planning Studies 

Planning studies often include exercises such as problem identification and other similar steps to 

ensure there is a connection between the project purpose and need and the geometric concepts 

being considered. Planning studies could include limited geometric concepts on the general type 

or magnitude of project solutions to support programming. 
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Alternatives Identification and Evaluation 

The project needs identified in prior planning studies inform concept identification, 

development, and evaluation. At this stage, it is critical to understand the project context and 

intended outcomes so potential solutions may be tailored to meet project needs within the 

opportunities and constraints of a given effort. FHWA describes context sensitive solutions as 

“... a collaborative, interdisciplinary approach that involves all stakeholders in providing a 

transportation facility that fits its setting”.(20) In considering the concept of “context sensitive 

design/solutions”, this stage calls for meaningful and continuous stakeholder engagement to 

progress through the project development process. 

Preliminary Design 

Concepts advancing from the previous stage are further refined and screened during preliminary 

design. For more complex, detailed, or impactful projects, the preliminary design (typically 30 

percent design level plans) and subsequent documentation are used to support more complex 

State or Federal environmental clearance activities. The corresponding increased geometric 

design detail allows for refined technical evaluations and analyses that inform environmental 

clearance activities. Preliminary design builds upon the geometric evaluations conducted as part 

of the previous stage (alternatives identification and evaluation). Some of the common 

components of preliminary design include: 

• Typical sections. 

• Horizontal and vertical alignment design. 

• Grading plans. 

• Traffic and intelligent transportation systems (ITS).

• Signing and pavement markings. 

• Illumination. 

• Utilities. 

Final Design 

The design elements are advanced and refined in final design. Typical review periods include 60 

percent, 90 percent, and 100 percent plans before completing the final set of construction plans 

and documents. During this stage, there is relatively little variation in design decisions as the 

plan advances to 100 percent. Functionally, in this stage of the project development process, the 

targeted performance measures have a lesser degree of influence on the form of the project. 

Construction 

Construction activities could include geometric design decisions related to temporary streets, 

connections, or conditions that facilitate construction. Project performance measures may relate 

to project context elements. 

SUMMARY OF QR INTERSECTION ADVANTAGES AND DISADVANTAGES 

As described in chapter 1 and the previous sections of this chapter, QR intersections have unique 

features and characteristics related to multimodal considerations, safety performance, operations, 

geometric design, spatial requirements, constructability, and maintenance. Table 3 provides an 

overview of the advantages and disadvantages of QR intersections for users, policy makers, 

designers, and planners to understand when considering this type of alternative intersection form. 
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35

Table 3. Summary of QR intersection advantages and disadvantages. 

MOEs Advantages Disadvantages 

NonMotorized 

Users 

• Reduces most crossing movements 

conflicts between vehicles & pedestrians. 

• Pedestrians & bicycles cross fewer travel 

lanes (shorter distance, less exposure). 

• Two-phase signal operations increase 

service time to pedestrians & bicyclists. 

• Some pedestrians and bicycles must 

cross additional signalized 

intersections, increasing total exposure 

and delays. 

Safety 

• Fewer overall intersection conflict 

points. 

• No left-turn conflicts (severe crash 

potential) at the main intersection. 

• Lower delay and fewer stops on major 

street could reduce rear-end crash rates. 

• Potential for driver confusion/error 

due to unfamiliarity with intersection. 

• Additional signalized intersections 

could increase overall crash rates. 

• Higher right-turn volumes increase 

those vehicle-pedestrian conflicts. 

Operations 

• Shorter cycle lengths and increased green 

time for through movements. 

• Significant delay reduction and travel 

time savings over conventional 

intersections. 

• Significantly reduced queues and 

spillback potential. 

• Potential increase in delay, travel 

distance, and stops for some left turns. 

• Potential disregard of left-turn 

prohibitions. 

• Potential increased weaving as drivers 

accustomed to making lefts from left 

side of the road now make right turns. 

Access 

Management 

• Potential for improved/controlled access 

to developments in some intersection 

quadrants. 

• Potential for circuitous access to land 

uses in some intersection quadrants. 

• May need to relocate adjacent streets 

and/or driveways to accommodate Tintersections. 

ROW / 

Space 

• Narrow ROW footprint due to lack of 

left-turn lanes at main intersection. 

• Reduced roadway width and/or increased 

space for non-motorized users. 

• If no existing roadway is repurposed, 

requires ROW for new roadway in one 

intersection quadrant. 

• Requires ROW 

acquisition/construction of new 

roadway in one intersection quadrant. 

Traffic 

Calming 

• Narrower roadway footprint gives visual 

cues to slow vehicle speeds. 

• Greater intersection throughput provides 

potential for fewer through lanes. 

• None. 

Construction/ 

Management 

• Construction of QR has minimal impact 

to either intersecting roadway. 

• QR can be used as detour route during 

construction and for maintenance. 

• Additional signage and pavement 

markings compared to conventional. 

• Construction and maintenance of two 

additional signals. 

Aesthetics 

• Quadrant provides opportunity for stormwater detention, park, or other civic 

value. 

• Quadrant area requires maintenance; 

could look blighted if unattended. 

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CHAPTER 3 — MULTIMODAL CONSIDERATIONS 

This chapter provides an overview of multimodal considerations at QR intersections and how 

provisions for pedestrians, bicycles, transit, and heavy vehicles should influence the overall 

planning and design of these intersections. Several of the guidelines presented here are based on 

elements of the AASHTO Green Book but are applied within the unique context of a QR 

intersection.(8) The overall objective is to develop a design, regardless of the type of intersection, 

compatible with a Complete Streets approach. Complete Streets are facilities that serve many 

types of users including freight, transit, and non-motorized users.

DESIGN PRINCIPLES AND APPROACH 

QR intersection planning and design should consider a variety of transportation modes and 

needs. When considering a QR intersection, the following elements should be evaluated: 

• The unique geometrics of the quadrant roadway and accessibility needs to surrounding 

intersection land uses must consider benefits and impacts to all transportation modes. 

• The interaction of the three signalized intersections and the unique operations that reduce 

the number of signal phases at QR intersections can introduce both opportunities and 

challenges for pedestrians, bicyclists, transit vehicles, and users with disabilities. 

• The prohibition of left-turn movements at the main intersection may create enforcement 

issues for automobiles and for bicycles if bicycle boxes, bicycle lanes, or other 

accommodations for direct left turns are not included in the design. 

• Large vehicles require adequate design at the secondary T-intersections to accommodate 

dual turn lanes and swept paths. Geometrics may include wider turning lanes, paved 

shoulders, bump outs, and mountable/traversable features. Intersection geometry and all its

associated movements need to accommodate the design vehicle for both crossing roadways.

Specific multimodal considerations are illustrated in figure 29 and described below.

• The reduced number of signal phases at the main intersection can make it easier to serve 

non-motorized movements compared to a multi-phase signal. At multi-phase signals, the 

need to provide adequate pedestrian clearance may result in the pedestrian movement 

controlling the phase lengths, leading to longer cycle lengths and greater pedestrian delay. 

In contrast, vehicle movements typically control phase length at two-phase QR intersection 

signals, which can better provide sufficient time per phase to serve pedestrians. 

• At the secondary T-intersections, pedestrians and bicyclists can cross both roadways under 

signal control but are exposed to right-turning vehicles. This is not dissimilar to pedestrian 

crossings at a conventional intersection; however, the number of right-turning vehicles are 

substantially increased at several locations were right turn volumes are combined with 

indirect left turns that make one or more right turns. 

• The QR intersection eliminates the need for left-turn lanes at the main intersection, which 

frees up ROW compared to a conventional intersection. This ROW can be used for 

multimodal facilities in the form of sidewalks, bicycle lanes, or transit facilities. 

• At the main intersection, pedestrian walk phases can be shorter, as curb-to-curb crossing 

distances are shortened not having to cross multiple left-turn lanes. Furthermore, as cycle 

lengths can be shorter at QR intersections compared to conventional intersections, 

pedestrians and bicyclists wait time is also shortened (more pedestrian cycles per hour). 
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© NCDOT 

Figure 29. Graphic. Multimodal considerations. 

• As QR intersections are often at locations with balanced approach volumes, pedestrian walk 

phases can be more equally distributed, providing added time for pedestrians, particularly 

pedestrians with disabilities. 

• Note that only two of three crosswalks are provided at the secondary T-intersections. 

Eliminating interior crosswalks limit pedestrian interaction with left-turning vehicles 

leaving the quadrant roadway at both secondary T-intersections. The placement and design 

of crosswalks is discussed in greater detail in chapter 7. 

Anticipating Multimodal Needs, Behavior, and Patterns 

A fundamental challenge in developing any new intersection form is deciding how to best 

provide for pedestrian and bicycle movements and anticipating the desire lines between different 

origins and destinations for these modes (e.g., how bicyclists, pedestrians, heavy vehicles, and 

transit vehicles travel through the intersection). Forecast volumes for non-motorized users are 

rarely available, and if they are, they typically do not capture travel patterns within the 

intersection. 
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Most QR intersections constructed to date feature pedestrian facilities and some provide separate 

bicycle facilities. For retrofit sites, the existing pedestrian and bicycle facilities were improved 

with construction of the QR intersection. QR intersection improvement projects at both the 

Huntersville, North Carolina and Front Royal, Virginia locations added sidewalks and pedestrian 

crosswalks on all roadways, and the Front Royal project also added a separate in-street bicycle 

facility on US-340/522. At three of these four QR intersection sites, the construction of 

multimodal facilities was a priority for agencies, garnering positive feedback from local residents 

and users for inclusion at each facility. 

At major intersections in suburban areas, pedestrian improvements and connectivity can 

sometimes lag land use development, as land uses are often required to only make improvements 

along their direct frontage and not provide connectivity through the intersection. QR 

intersections are well suited in built-up environments where development is already present in 

one or more intersection quadrants and where roadway capacity has not been improved in recent 

years. Therefore, early consideration and provision for pedestrian, bicycle, transit, and heavy 

vehicle movements should be a priority consideration for QR intersection projects where not 

already present and should be accounted for early in the planning and design phases. 

The remainder of this chapter describes the unique characteristics of the primary multimodal 

modes of pedestrians, bicyclists, transit, and heavy vehicles that should be considered when 

analyzing and designing QR intersections. Transportation professionals need to work to identify 

and understand the needs of these various user groups to produce a balanced design that serves 

them all. 

PEDESTRIANS 

The inclusion of pedestrian facilities should receive attention and consideration throughout the 

design process. This section describes QR intersection design features, considerations, and tradeoffs relating to the pedestrian mode. 

Pedestrian facilities should be planned, designed, and constructed to emphasize pedestrian 

convenience and safety, which is achieved through appropriately sized sidewalks, vertical and 

horizontal separation from adjacent travel lanes, minimized pedestrian crossing distances, clearly 

defined pedestrian paths, adequate time to cross, and low vehicular speeds. Landscaping and 

other aesthetic treatments can contribute to a positive pedestrian experience. 

Potential benefits for pedestrians at QR intersections include: 

• Reduced pedestrian-vehicle conflict points. 

• Shorter pedestrian crossing distances and safe refuge areas (less pedestrian exposure). 

• Longer, more frequent pedestrian crossings. 

Pedestrian-Vehicle Conflict Points 

Pedestrians crossing a QR intersection encounter fewer conflicting traffic streams than at a 

conventional intersection. At a conventional intersection, pedestrians cross the street with onestage or two-stage crossings during the vehicle phase of the adjacent street. Figure 30 shows 

pedestrian conflict points with vehicle movements that pedestrians experience at a conventional 

intersection. 
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 © NCDOT 

Figure 30. Graphic. Pedestrian-vehicle conflict points at a conventional intersection. 

Figure 31 shows pedestrian conflict points with traffic movements at a QR intersection. At the 

main intersection, crosswalks can be marked across all intersection legs, as at a conventional 

intersection. Pedestrians at a QR intersection cross one roadway during the through and rightturn signal phase for the other roadway, leaving only pedestrian-vehicle conflicts with opposing 

street right-turning vehicles making a right-turn-on-red (RTOR). 

 © NCDOT 

Figure 31. Graphic. Pedestrian-vehicle conflict points at QR intersection. 

Because the QR includes three signalized intersections, the total number of vehicle-pedestrian 

conflict points at a QR intersection (32 conflict points) is greater compared to a conventional 

intersection (24 conflict points). However, the exposure to pedestrians in the crosswalk is 
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reduced for a QR intersection since left-turn movements are eliminated at the main intersection, 

and the length of the crossings are often reduced compared to conventional intersections. Due to 

be published in 2020, NCHRP 7-25 will provide procedures to evaluate pedestrian and bicycle 

operations and safety for a variety of alternative intersection forms including the QR intersection. 

Figure 32 shows the eight sidewalk origins and destinations (A through G) at a QR intersection. 

Assuming there are no pedestrians making U-turns and none destined for the interior of the 

quadrant roadway, each of the 8 origins have 6 potential destinations, for a total of 48 pedestrian 

origin-destination (O-D) pairs. Of those 48 pairs, only 8 O-D paths (17 percent) require 

pedestrians to cross an additional crosswalk compared to a conventional intersection. These 

paths are: A to F, B to F, C to G, and D to G (and their reciprocals). All other pedestrian O-D 

pairs make the same number of intersection crossings compared to a conventional intersection 

and are benefited by having shorter crossing distances (less exposure to vehicles) and longer 

walk times. In addition, two O-D pairs can walk along the quadrant roadway (E to G, E to H, F 

to G, and F to H and their reciprocals), shortening the distance a pedestrian must travel. 

Note that at the secondary T-intersections in figure 32, only two of three approaches include 

crosswalks. Omitting the one particular crosswalk eliminates pedestrian conflicts with vehicles 

turning left out from the quadrant roadway. Greater details on T-intersection crosswalk 

placement is included in chapter 7. 

 © NCDOT 

Figure 32. Graphic. Pedestrian movements through a QR intersection. 
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Pedestrian Crossing Distances 

Because there are no left-turn lanes at the main intersection of a QR intersection, the curb-tocurb pedestrian crosswalk distance is typically shorter. At a conventional intersection, 

pedestrians must cross the width of the through lanes of travel in both directions, plus a single or 

dual left-turn lane(s) and often a right-turn lane. This length increases the exposure time for 

pedestrians as well as the length of the pedestrian walk/don’t walk phase. Figure 33 and figure 

34 compare the pedestrian crossing distance at the main intersection of a QR intersection with a 

conventional intersection (both assuming two through lanes in each direction and 8-ft medians). 

The pedestrian crossing distance under the QR intersection (figure 33) is approximately 80 ft 

compared to the approximate 104 ft to cross at a conventional intersection (figure 34), a 30-

percent reduction in pedestrian exposure to vehicular traffic. 

© NCDOT 

Figure 33. Graphic. Conventional intersection crosswalk distances. 

© NCDOT 

Figure 34. Graphic. QR intersection crosswalk distances. 

At conventional intersections, intersection width can dictate the length of signal phases to allow 

pedestrians to safely cross during the adjacent street through vehicle phase. Conventional 

intersections often display very short “walk” phases to reduce the pedestrian impacts to signal 

phases and cycle lengths. The shorter crosswalk lengths at a QR intersection allow greater phase 

flexibility and pedestrian safety to be built into each signal cycle. At QR intersections, since 

there are only two signal phases (that are often close to being equal), pedestrians can receive 

longer “walk” times, and crossing lengths are less of an impact to vehicle signal phase lengths. 
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Pedestrian Crossing Time 

A third benefit to pedestrians is gained by the two-phase signal operations at the main 

intersection. Two-phase operations can result in a shorter signal cycle length (meaning more 

pedestrian crossing phases per hour), while providing additional walk time for pedestrians to 

cross the intersection. Figure 35 shows the pedestrian “walk”, flashing “don’t walk” and “Don’t 

Walk” indicator progression for pedestrians crossing Street 1 at a conventional intersection. 

Figure 36 shows that QR intersections can increase the time allotted for pedestrian crossing both 

streets during each signal cycle despite an overall decrease in signal cycle length (CL). The 

greater number of signal cycles per hour also provides more pedestrian crossing time per hour 

and a shorter wait time for pedestrians between signal cycles. 

© NCDOT 

Figure 35. Graphic. Pedestrian walk phases at a conventional intersection. 

 © NCDOT 

Figure 36. Graphic. Pedestrian walk phases at a QR intersection. 

Pedestrian-Focused QR Intersection Design 

Pedestrian safety and comfort are enhanced by reduced vehicle speeds, good driver-to-pedestrian 

sight distances, and appropriate crosswalk locations. At QR intersections, there are opportunities 

at both the crossing and secondary T-intersections for pedestrian-focused designs through the use 

of reduced curve radii, enhanced pedestrian crossings, and other geometric details. Key concepts 

underlying pedestrian-focused design of QR intersections include: 

• Tighten vehicle curve radii to reduce speeds at the crosswalk. Lower vehicle speeds have 

been linked in research to increased driver yielding rates as well as lower risk of serious 

injury or death for the pedestrian in the case of a crash. 

• Provide adequate sight distance for vehicle approaches to crosswalks by limiting roadside 

obstacles. Improved vehicle sight distance also provides enhanced pedestrian sight distance 

to make adequate gap crossing decisions at unsignalized crossings. 

• Where right-turn channelizing islands are needed, provide one vehicle length of storage 

downstream of the crosswalks for yield-controlled vehicle movements. Similar to the 

crosswalk placement at roundabouts, this separates the driver decision points of yielding to 

pedestrians at the crosswalk and screening for gaps at the yield sign. It also prevents drivers 

waiting at the yield line from blocking the crosswalk with their vehicle. 
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• Locate crosswalks behind the stop bar for signalized vehicle turns, consistent with driver 

and pedestrian expectations at signalized intersections. 

Typical QR intersections include signalization at all three intersections, with possible variations 

such as the use of roundabouts described in the earlier chapter. Lighting of all intersections and 

crosswalks is often cost-feasible and generally beneficial to pedestrian safety and should be 

included in cost estimates to benefit pedestrian visibility and safety. 

ADA and PROWAG Accessibility Considerations 

Accessibility was previously described in chapter 2 in the broader context of considering a 

project’s built and planned environment and the ability for various users to approach a desired 

destination or potential opportunity for activity using highways and streets (including the 

sidewalks and/or bicycle lanes provided within those ROW). In this section, accessibility is 

explicitly focused on the policies related to American with Disabilities Act (ADA) and Public 

Rights-of-Way Accessibility Guidelines (PROWAG). Special consideration should be given to 

pedestrians with disabilities, including accommodating pedestrians with vision or mobility 

impairments. Being relatively new on a national level, specific guidance for “Accessible QR

intersections” is not yet available. However, general accessibility principles can be borrowed 

from other forms of intersections and applied here. The United States Access Board provides 

many additional resources on accessibility and specific requirements for Accessible Public 

Rights of Way, which the transportation professional should refer to and become familiar with, 

in addition to AASHTO guidance.(18) 

All pedestrians—but especially those with vision, mobility, or cognitive impairments—may 

benefit from targeted outreach and informational material created with pedestrians in mind. 

These outreach materials include information on crosswalk placement and intended behavior, as 

well as answers to frequently asked questions. For blind pedestrians, materials need to be 

presented in an accessible format with descriptions of distinct features of the QR intersection. 

Pedestrians with vision, mobility, or cognitive impairments should find crossing QR 

intersections similar to crossing a conventional intersection. Either intersection form requires 

crossing multiple through travel lanes and generates conflicts with right-turning vehicles. In 

general, intersection crossings can be accommodated with traditional design techniques. The 

cues that pedestrians with vision impairments rely on to cross intersections, such as the sound of 

traffic parallel to their crossing, are similar in QR and conventional intersection forms. The direct 

crossing paths of a QR intersection are relatively easy and convenient to use. All pedestrians will 

experience two-phase signal timing and a reduced number of conflicting traffic streams. 

The basic principles for accessible design can be divided into the pedestrian walkway and the 

pedestrian crossing location. For the pedestrian walkways, the following considerations apply: 

• Provide sufficient space (length, width) and recommended slope rates for wheelchair and 

other non-motorized users such as people pushing strollers, walking bicycles, and others. 

• Construct an appropriate landing with flat slope and sufficient size at crossing points. 

For pedestrian crossing locations, these additional considerations apply: 

• Provide curb ramps and detectable warning surfaces at the transition to the street. 

• Separation of the pedestrian path from the back of curb and delineation of the pedestrian 

route using curbing, vegetative, or other type of buffer. 
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• Provide accessible pedestrian signals with locator tone at signalized crossings.

• Locate push-buttons to be accessible by wheelchairs and adjacent to the crossing at a

minimum separation of 10 ft.

• Use audible speech messages where spacing is less than 10 ft, or where additional narrative

for the expected direction of traffic is needed.

• Align crosswalk landings to the intended crossing direction.

• Crosswalk width through the intersection should be wide enough to permit pedestrians and

wheelchairs to pass without delay from opposing directions.

• Use high-visibility crosswalk markings (this is important for low-vision pedestrians and can

make the crosswalk more detectable to motorists).

Figure 37 illustrates a QR intersection pedestrian crossing in Front Royal, Virginia that includes 

many of the aforementioned considerations.

 NCDOT

Figure 37. Photo. Example of pedestrian wayfinding provision via curbing. 

BICYCLISTS

QR intersections are most often found in urban and suburban settings along arterials or other 

high-volume streets where bicycle accommodations are less likely to be included. However, the 

current trend in many communities is to integrate Complete Streets policies that include bicycle 

accommodations on all types of streets. Figure 38 illustrates bicycle lane accommodations at the 

Front Royal, Virginia QR intersection, including marked bicycle lanes on US-340/522. 
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46 

  NCDOT

Figure 38. Photo. Bike lanes at Front Royal QR intersection. 

At QR intersections, through and right-turning bicyclists receive higher percentages of green 

time at QR intersections compared to conventional intersections. Where vehicular right turns are 

in conflict with bicycle lanes, an increasingly common practice is to shift the right-turn lane to 

the right of the bicycle lane upstream of the signalized intersection, as illustrated in figure 39. 

This clearly identifies the conflict areas between though bicyclists and right-turning vehicles. 

 Source: FHWA

Figure 39. Graphic. Right-turn lane with bicycle lane.

Options for Bicycle Accommodation at QR Intersections

Three basic options exist for accommodating bicyclists at QR intersections. These options 

include providing: 

1. Shared-lanes on one or both roadway, which may include the use of wider shoulders or 

bicyclists using the vehicular travel lane. For this option, “sharrow” markings can 

reinforce to motorists that bicyclists are legal roadway users. 
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2. A defined bicycle lane on one or both roadways through the QR intersection. For this 

option, pavement markings can reinforce to drivers that the bicycle lane is not a shoulder. 

Along higher-speed roads, buffered bicycle lanes are preferred.

3. A separated multi-purpose or shared-use path. 

Each of these options may be viable in certain locations; the choice depends to a large extent on 

the expected use of the facility by bicyclists, the expected behavior of these bicyclists, location 

of local and regional destinations (schools, shopping, employment centers, parks), and the 

available ROW on both roadways. Without a bicycle lane, experienced bicyclists are likely to 

use the vehicular travel lanes while recreational bicyclists may use the sidewalk or vehicular 

lanes (depending on their speed differential with pedestrians and/or local bicycle ordinances). 

As direct left-turn lanes are removed from the main intersection in a QR design, left-turning 

bicyclists have three options for navigating a QR intersection: 

A. Bicyclists making a “two-stage left-turn” using bicycle box: Bicyclists on both roadways 

approach the intersection and follow the vehicle signals. When receiving a green phase, the 

bicyclists proceed across the intersection and stop in a bicycle left-turn queue box on the 

right. When the crossing street receives a green indication, bicyclists proceed along with the 

crossing street traffic. Signage on both streets should reinforce the auto no left-turn 

movement against crossing autos and bicycles. One option is to use R3-5a mandatory 

movement lane control signs (i.e., straight ahead only) for the auto lanes. This option is most 

desirable for bicyclists. Figure 40 illustrates the two-stage bicycle left turn placement. Figure 

41 illustrates a typical in-street bike-box pavement marking. 

 Source: FHWA

Figure 40. Graphic. Bicycle two-stage crossing path.
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 Source: FHWA

Figure 41. Graphic. Bicycle in-pavement bike box.

B. Bicyclists cross following “pedestrian rules”: Bicyclists approach the intersection and 

instead of traveling through based on the vehicle indications, exit the street to the right and 

follow the “walk”/ “don’t walk” indications (just as a pedestrian would).

C. Bicyclists cross following “vehicle rules” using the quadrant roadway: Under this option, 

bicycle lanes would be included on both sides of the quadrant roadway. Each bicycle left turn 

approaching from all four directions would take a different path. Two of the paths may be 

considered intuitive to bicyclists, while the other two paths create two-stage crossings at the 

secondary T-intersections. Figure 42 and figure 43 illustrate each bicycle movement path and 

each movement path is described following each figure. 
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 © NCDOT 

Figure 42. Graphic. D Street bicyclists left turns following quadrant roadway. 

Path 1: Bicycles turn right at the first T-intersection onto the quadrant roadway with rightturn vehicles under signal control (or as RTOR) and then turn left at the second Tintersection with the left-turn vehicle phase. All bicycle movements operate under protected 

signal phases, but the total distance traveled by bicycles is increased compared to the 

conventional two-stage option. 

Path 2: Bicycles pass through the main intersection and turn left by making a two-stage 

crossing with pedestrian movements on the near and quadrant sides of the first T-intersection. 

These movements are inconvenient for experienced bicyclists who must cross with 

pedestrians and may wait for crossing phases at two locations. Bicycles would then traverse 

the quadrant roadway then right at the second T-intersection with right-turn vehicles under 

signal control (or as RTOR). All bicycle movements operate under protected signal phases, 

but the total distance traveled by bicycles is increased compared to the conventional twostage option. 
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 © NCDOT 

Figure 43. Graphic. A Street bicyclists left turns following quadrant roadway. 

Path 3: Bicycles turning left at the first T-intersection do so by making a two-stage crossing 

on the near and quadrant sides of the T-intersection, crossing with pedestrian movements. 

These two movements are inconvenient for experienced bicyclists who must cross with 

pedestrians and may wait for crossing phases at two locations. Bicycles would traverse the 

quadrant roadway then turn left at the second T-intersection with the left-turn vehicle phase. 

All bicycle movements operate under protected signal phases, and the total travel distance is 

slightly reduced compared to the conventional two-stage option. 

Path 4: Bicycles pass through the main intersection and turn right onto the quadrant roadway 

with right-turn vehicles under signal control or as RTOR and then turn right at the second Tintersection with right-turn vehicles under signal control or as RTOR. All bicycle movements 

operate under protected signal phases, but the total distance traveled by bicycles is increased 

compared to the conventional two-stage option and bicyclists travel through the main 

intersection twice. 

Of the three options for bicycle left turns, the “two-stage left-turn” option is the most natural for 

bicyclists and the most likely to be obeyed. The “pedestrian rules” option can be considered 

when upgrading sidewalks to multi-use paths, or when an otherwise off-street bicycle path 

crosses the street at the intersection. The “vehicle rules” option is least desirable, as several 

movements require two-stage crossing at the secondary T-intersection (not meeting bicyclist 

expectations), bicycle travel distance is increased for most movements and there is additional 

cost to construct bicycle lanes on the quadrant roadway. 
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Bicycle-Pedestrian Conflicts 

Potential pedestrian-bicycle conflicts exist in those cases where bicycles are expected to use the 

pedestrian walkway and sidewalk system. Just as there is a speed differential between motorized 

traffic and bicycles, there is also a speed differential between bicycles and pedestrians, unless 

bicyclists choose to dismount on the sidewalk. The minimum width of a shared-use path is 10 ft 

except in very rare circumstances. Wider paths, or fully separated bicycle paths, may be needed 

in cases where high pedestrian and bicycle volumes are expected at a QR intersection, such as 

when a path or trail system goes through an interchange. 

TRANSIT VEHICLE CONSIDERATION 

Rail or Bus Rapid Transit 

The QR intersection does not introduce any unique benefits or fatal flaws for light-or heavy-rail 

transit (LRT or HRT) and bus rapid transit (BRT) vehicle crossings. However, if choosing which 

intersection quadrant to place the QR is an option, there would be an advantage for the rail 

crossing to be located along the top end of a secondary T-intersection so that there is no track 

crossing the quadrant roadway, as illustrated in figure 44 and figure 45. 

 © NCDOT 

Figure 44. Graphic. Desirable QR intersection rail crossings. 

 © NCDOT 

Figure 45. Graphic. Less desirable QR intersection rail crossings. 
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This would also help preserve the T-intersection operations, as a fourth leg would create an 

undesirable additional track crossing. The transit line crossing of the main intersection would be 

planned and designed similar to transit crossings at any conventional intersection. The QR main 

intersection has a slight advantage because the rail line would not have to cross any left-turn 

lanes. A special phasing plan would have to be included for all three intersections that would 

preempt the roadway crossing the track and would systematically clear the intersection after the 

crossing is cleared.

At the time of this publication, there are no known examples of LRT or BRT corridors running 

through a QR intersection.

Bus Transit

The QR intersection does not introduce any unique movements for buses traveling through the 

intersection compared to a conventional intersection. Buses on the major street can operate using 

the right lane on both intersecting roadways and make stops before or after the main intersection

in the same manner as conventional intersections, while receiving more green time and incurring 

less delay. Bus routes turning left at the intersection would follow the rules of the QR 

intersection, which will add additional travel distance for buses, but typically will not increase 

the overall travel time for buses. There is an advantage to left-turning buses. At a conventional 

intersection, left-turning buses must leave the right (curb) lane and weave across through lanes to 

gain access to left-turn lanes at the main intersection. Under a QR intersection, two of the leftturn movements allow buses to stay in the right lanes and use the quadrant roadway to complete 

the left-turn movement.

Bus Stop and Transfer Locations

If transit service is only provided along one of the interesting roadways, providing a far-side bus 

stop downstream of the secondary T-intersection is preferred (including a bus-bypass lane as 

possible) to allow buses to take advantage of signal progression, support green-extension transit 

signal priority treatments and avoid blocking right-turn movements. If transit service is provided 

on both streets, then transfer opportunities between bus lines should also be considered. This 

may involve a combination of a nearside stop on one street and a far-side stop on the other street, 

allowing transfer movements to be made by simply walking around the corner of the 

intersection. In that case, buses stopping at a nearside stop in a right-turn lane should be 

exempted from the right-turn requirement and possibly provided with a queue-jump phase to 

assist them in leaving the stop. Figure 46 illustrates potential locations for the near-side and farside bus stop locations.

Additionally, bus stops may be located on the quadrant roadway (if buses are not making through 

movements), where their stopping impact may be lessened compared to stops on the higher 

volume intersecting roadways. However, considerations should be given to the fact that bus stop 

locations on the quadrant roadway may be inconvenient and/or less intuitive for the pedestrian to 

discover and walk to the bus stop locations. Stops should not be located in any areas on the 

quadrant roadway where there is only a single lane, or where transit stops could block QR 

intersection operations.
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© NCDOT 

Figure 46. Graphic. Potential bus stop locations. 

HEAVY VEHICLE CONSIDERATIONS 

The typical QR intersection can easily be designed to accommodate heavy vehicle movements at 

the main intersection, as heavy vehicles are not permitted to turn left at the main intersection, so 

focus should be on making the right-turn curb radii adequate for the design vehicle. The 

secondary T-intersections should be designed using truck turning templates according to the 

design vehicle (typically a WB-67 vehicle) to provide adequate turning radii and tracking for 

both the front and rear ends of trucks. This may impact the raised median nose design, turn lane 

widths, location, and curb radii and is typical for the design of any conventional T-intersection. 

Should the QR intersection be located on an identified OSOW vehicle route, additional design 

modifications may be required, including wider lanes on the quadrant roadway, the use of 

mountable curbs and/or pavement bulb-outs as deemed necessary.

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CHAPTER 4 — SAFETY 

This chapter discusses safety principles and performance for QR intersections, including 

geometric design and human factors that potentially impact safety. Safety performance and 

observations are presented, as well as discussions of specific safety issues or concerns not typical 

at conventional intersections. 

An appropriate level of safety assessment corresponding to the stage of the project development 

process (planning, alternatives identification and evaluation, preliminary design, final design, 

and construction) supports decisions about QR intersections. The analysis should be consistent 

with the available data, and the data should be consistent with the applied tools. Multimodal 

safety principles, including vehicle-pedestrian and vehicle-bicycle conflict points, accessibility, 

and crossing options, are discussed in chapter 3. 

SAFETY PRINCIPLES 

The change in safety performance associated with the conversion of a conventional intersection 

to a QR intersection is highly dependent on the existing conditions and expected change in traffic 

and turning movements. For example, converting two existing stop-controlled intersections to 

traffic signals has the potential to improve safety performance based on the crash modification 

factors (CMFs) presented in the Highway Safety Manual. However, this depends on the existing 

safety performance of the intersections since rear-end crashes are expected to increase while leftturn and angle crashes are expected to decrease. If there are relatively few left-turn and angle 

crashes, then the traffic signals may not provide a further safety benefit. 

Concerns have been raised that QR intersections could increase crashes because two new 

signalized intersections are created. Based on the Highway Safety Manual, any new signalized 

intersection is expected to increase the frequency and potentially the severity of crashes 

compared to a similar roadway segment with no signalized intersection. The long-term expected 

frequency and severity of crashes at each new intersection is dependent on the specific geometric 

and operational characteristics such as traffic volumes, turning movements, presence of left- and 

right-turn lanes, permissive or protected left-turn phase, and allowance or prohibition of rightturn-on-red. 

As described previously, another safety concern is related to vehicle-pedestrian conflict points. 

While total vehicle-pedestrian conflict points increase by 50 percent compared to a conventional 

intersection, the conflict point characteristics differ. As more QR intersections are constructed, 

data collection on the pedestrian safety experience will be of significant value. 

However, there is some thought that QR intersections can improve intersection safety by 

reducing the overall number of vehicle-vehicle conflict points, changing the type of conflict 

points, and redistributing turning movements: 

• Reduced vehicle-vehicle conflict points: There is a net change of two fewer vehiclevehicle conflict points for a QR intersection compared to a conventional intersection: six 

fewer crossing conflict points, two more merging conflict points, and two more diverging 

conflict points. 
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• Change in conflict types: Crossing path crashes tend to be more severe than merging and 

diverging crashes. While there is an increase in the number of merging and diverging 

conflict points, there may be a net benefit in crash severity for vehicle-vehicle crashes 

because of the larger reduction in crossing conflict points. 

• Redistribution of turning movements: Left-turn conflict points are transferred to the 

secondary T-intersections where the intersection volumes are lower, conflict points are 

fewer, and the intersection is smaller, making it easier for drivers to focus on potential 

conflicts (fewer decision points). 

Also, as an indirect benefit, relocating and managing uncontrolled driveways near an intersection 

to the low-volume, low-speed quadrant roadway can result in overall safety benefits.

Reduced Vehicle-Vehicle Conflict Points 

While crash data are often used to develop models or other tools that can ultimately help 

professionals make safety decisions about transportation facilities, crash data are often limited or 

completely unavailable for some types of facilities. In lieu of crash data, one often-applied 

strategy is to examine the number of conflict points at an intersection. While no mathematical 

relationship between conflicts and collisions has been clearly documented, conflicts are 

intuitively correlated with collisions and are often used as a surrogate measure, particularly to 

compare different intersection forms. It is common to consider both lane-by-lane conflicts and an 

aggregated conflict analysis that treats each movement as one lane; the latter approach will be 

presented here for the sake of simplicity. 

Figure 47 and figure 48 identify the vehicle conflict points at conventional and QR intersections, 

respectively. By restricting direct left turns at the main intersection, QR intersections reduce 

vehicular intersection conflict points from 32 to 30. This includes the remaining conflict points at 

the main intersection (12) and the conflicts introduced by the QR at both secondary Tintersections (9 each), for a total of 30. 

 © NCDOT 

Figure 47. Graphic. Vehicle-vehicle conflict points at conventional intersection. 
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 © NCDOT 

Figure 48. Graphic. Vehicle-vehicle conflict points at QR intersection. 

Removing direct left turns at the main intersection also reduces some of the vehicular crossing 

conflict points that tend to be associated with higher crash severity, including left/through angle 

(or “T-bone”) collisions. As shown in table 4, the QR intersection reduces crossing conflict 

points from 16 at a conventional intersection to 10 over all 3 QR intersections (a 38-percent 

reduction). While no mathematical relationship between conflict points and crashes has been 

determined, conflict points are often used as a surrogate measure, particularly to compare 

different intersection. 

Table 4. Conflict point comparison. 

Intersection Type Crossing Merging Diverging Total 

Conventional Intersection 16 8 8 32

QR Intersection* 10 10 10 30

*totals for all three intersections 

If a roadway is connected as a fourth leg at either of the T-intersections (and no turns are 

restricted), the number of conflict points would substantially increase from 9 to 32 at the fourth 

leg / quadrant roadway full-movement intersection and from 30 to 53 for the overall QR 

intersection. 

Human Factors Principles and Considerations 

Based on human factors and driver expectation, motorists expect to make left turns at the main 

intersection. Drivers desiring to make a left turn do not expect the prohibition of direct left turns 

at QR intersections. Furthermore, motorists approaching a conventional intersection where they 

intend to make a left turn are accustomed to positioning their vehicles in the left lane(s) 

approaching the intersection, and motorists approaching an intersection where they intend to 

make a right turn position their vehicle in the right lane(s). Lastly, all of the left-turn movements 

and one right-turn movement are made at a different location than would be expected at a 

conventional intersection. 
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Figure 49 through figure 52 illustrate the QR intersection left-turn patterns from each approach 

(assuming the quadrant roadway is in the southeast intersection quadrant). Each of the four QR 

intersection left turn movements are unique and can have significantly different geometric and 

operational impacts. Using “Main” and “Quadrant” as references, the intersections that each left 

turn crosses through in order are: 

• Main-Through, Quadrant-Left, Quadrant-Right (MT-QL-QR).

• Quadrant-Left, Quadrant-Left (QL-QL). 

• Quadrant-Right, Quadrant-Left, Main-Through (QR-QL-MT).

• Main-Through, Quadrant-Right, Quadrant-Right, Main-Through (MT-QR-QR-MT). 

© NCDOT; Background image: © Google® EarthTM Accessed 2018 

Figure 49. Graphic. QR intersection MT-QL-QR pattern.

© NCDOT; Background image: © Google® EarthTM Accessed 2018 

Figure 50. Graphic. QR intersection QL-QL pattern. 
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© NCDOT; Background image: © Google® EarthTM Accessed 2018 

Figure 51. Graphic. QR intersection QR-QL-MT pattern. 

© NCDOT; Background image: © Google® EarthTM Accessed 2018 

Figure 52. Graphic. QR intersection MT-QR-QR-MT pattern. 

Examining the QR intersection left-turn patterns, some interesting human factor and driver 

expectation characteristics can be noted: 

• For the two left-turn patterns NOT ending in MT (figure 49 and figure 50), the left-turn 

movements both meet the driver expectation of turning left from the left side of the 

roadway. Both movements require adequate signing and marking (discussed in greater 

detail in chapter 8) to instruct motorists to make their desired left-turn movement prior to or 

after the main intersection. Once on the quadrant roadway, additional signing and marking 

is needed to guide motorists through the completion of their left-turn movement. 
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• For the two left-turn patterns beginning with QR (figure 51 and figure 52), left turns are 

made by first turning right, which does not meet driver expectation of turning left from the 

left side of the roadway. The QR-QL-MT movement must be clearly communicated to 

motorists by ground-mounted signs (at minimum) or overhead signs (desirable) in advance 

of the secondary T-intersection, as discussed later in chapter 8. 

• The MT-QR-QR-MT movement (figure 52) is the least intuitive and the most challenging 

movement to communicate to motorists. Therefore, this movement deserves the greatest 

attention in the project planning and design phases. Clear, concise signing must be provided 

far enough in advance of the intersection to direct motorists desiring to make a left turn to 

move to the right side of the roadway and proceed through the main intersection before 

making a right turn at the downstream secondary T-intersection. Without proper signing 

and marking, motorists expecting a conventional left turn are likely to approach the 

intersection on the left side of the roadway, realize the left-turn prohibition at the main 

intersection, and then try to cross one or more lanes to the right in a short distance to turn 

right onto the quadrant roadway. Every effort should be made to reduce occurrences of this 

challenging movement. 

One potential way to mitigate the driver expectancy concern of the MT-QR-QR-MT movement 

is to build a U-turn downstream of the main intersection. Vehicles would pass through the main 

intersection, make a U-turn at a downstream location and then make a right turn (MT-UT-RT). 

This U-turn movement could be signed and marked to replace the MT-QR-QR-MT movement, 

or serve as an option to capture vehicles unfamiliar with the QR design, giving them the option 

to stay in the left-most lane approaching the secondary T-intersection. In either case, attention 

should be given to the design of the U-turn to ensure it has the geometric and operational 

capacity to accommodate the U-turn demand. 

A second alternative would be to integrate the U-turn movement into the signal at the secondary 

T-intersection, similar to an RCUT intersection (as described in the FHWA RCUT Informational 

Guide).(21) This hybrid concept would require full access control of the secondary T-intersection 

(no possibility of a fourth leg) and may require creation of a bulb-out to accommodate larger 

design vehicle U-turn movements, likely requiring additional ROW. The U-turn can be aligned 

with the beginning of the right-turn lane for the main intersection, providing continuity for the 

left-turn path. This QR / RCUT hybrid concept is illustrated in figure 53. 

Note that this hybrid U-turn concept reduces the travel distance for left-turning vehicles from one 

approach compared to the typical QR intersection and would also replace a right turn movement 

with a through movement, resulting in added efficiencies. 
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 © NCDOT 

Figure 53. Graphic. Hybrid QR intersection with U-turn at secondary T-intersection. 

SAFETY CONCERNS 

The QR intersection introduces some unique safety concerns not present at conventional 

intersections. These concerns are discussed in the following sections. 

Potential for Violating Left-turn Prohibitions 

While signing and geometric design can deter motorists from making direct left and/or U-turns at 

the main intersection, there is no physical barrier to prevent left turns or U-turns. Proper 

overhead and ground-mount signing and markings, combined with proper geometric design that 

positively guides vehicles through a QR intersection, are all important factors in discouraging 

prohibited left turns at the main intersection. 

The QR is a relatively new design with limited implementations, and thus will not be common to 

drivers upon opening. Figure 54 shows illegal movements captured on video cameras shortly 

after the opening of the Huntersville QR intersection. Because of the learning curve associated 

with this new design, several QR intersection openings have included State or local police forces 

being used during the first days of operations to reinforce the turning prohibitions through the 

issuance of warnings and citations, providing a deterrence from improper intersection use. 
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© Town of Huntersville, NC 

Figure 54. Photo. Traffic camera capture of illegal turns at QR intersection. 

Intersection Spacing 

The QR intersection introduces two new traffic signals—one on each roadway approaching the 

main intersection. The optimal signal spacing between main and secondary T-intersections is 

approximately 500 ft, depending on left-turn volumes and storage capacity needs. This spacing 

may not meet individual State or local jurisdiction signal spacing or median opening guidelines. 

Some State DOT policies require minimum signalized intersection spacing of 600 or 800 ft. 

Quadrant roadways that must meet 800 ft intersection spacing will impose significantly greater 

travel time and delays for motorists using the QR intersection. This is discussed in greater detail 

in chapter 7. 

On the other end of the spectrum, excessively close intersection spacing may confuse motorists 

who may not be able to distinguish and make stopping decisions at successive intersections. In 

the two directions where motorists must pass through a secondary T-intersection then the main 

intersection (in that order of succession), it is important that there is sufficient braking distance 

for the second signal after the vehicle has cleared the first so that motorists can make 

independent decisions to stop or proceed through each intersection. Figure 55 presents the 

AASHTO formula for braking distance, which is based on approach speed, vehicle deceleration 

rates, roadway grades, and perception-reaction time. 

Figure 55. Equation. Calculation of safe stopping distance. 
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The parameters in figure 55 include: 

SSD = required stopping sight distance (SSD). 

V = vehicle speed, in mph. 

t = perception-reaction time, typically 2.5 seconds for design. 

g = roadway grade in percentage (downhill has negative value). 

a = vehicle deceleration rate, typically 11.2 ft/s. 

g = roadway grade (in decimal form). 

The goal is for the SSD for the main intersection (SSD1) to be lower than the distance between 

the main and secondary T-intersection. This would allow motorists to clear the first signal before 

reacting to the second, as illustrated in figure 56.

© NCDOT

Figure 56. Graphic. QR intersection braking distances.

Based on the stopping sight distance formula in the equation above, table 5 provides the 

calculated SSD based on roadway speeds and grades, which can be used to determine minimum 

spacing distance between the main and secondary T-intersections for a given location. Note that 

table 5 results are only meant to be used as a guide for planning QR intersection spacing in the 

project planning stage. The calculation of SSD for the purposes of determining signal clearance 

times should be performed in final design. 

Table 5. Minimum intersection spacing by stopping sight distance. 

Roadway 

Speed (mph) 

Roadway 

Speed (ft/s) 

SSD1 (ft) 

Grade=0%

SSD1 (ft) 

Grade=3% 

SSD1 (ft) 

Grade=-3%

35 mph 51 ft/s 246 237 257

40 mph 59 ft/s 300 288 315

45 mph 66 ft/s 360 344 378

50 mph 74 ft/s 423 404 446

55 mph 81 ft/s 492 469 520
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Queue Storage 

Another design and safety consideration for QR intersections is providing sufficient queue 

lengths to reduce the possibility of queues backing up into the through lanes and particularly the 

crossing or secondary T-intersection. Sufficient queue storage is most critical in three areas of a 

QR intersection, as illustrated in figure 57 and described below. 

1. Downstream left storage between intersections. The left-turn storage capacity on D 

Street is governed by the distance between the crossing and secondary T-intersection. To 

maximize storage length, the turn-lane taper begins just downstream of the main intersection. 

The QR signal phasing provides more green time for the left-turn movement and more cycles 

per hour compared to a conventional intersection, and in most cases, a single left turn with 

adequate storage should meet left-turn demands. However, since the left-turn lane is 

downstream of the main intersection, left-turn vehicles that depart the main intersection will 

need to be stored in this left-turn lane until the lagging protected left-turn phase begins. 

© NCDOT 

Figure 57. Graphic. Queue storage areas of concern. 
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2. Upstream left-turn storage at secondary T-intersection. There is less of a concern 

about queue spillback into the main intersection on A Street. However, providing adequate 

left turn storage at this upstream secondary T-intersection must consider impacts to 

driveways and intersections downstream from this intersection. 

3. Queue storage on the quadrant roadway. This distance should be analyzed to determine 

sufficient storage based on the exiting quadrant roadway volumes (at both ends), the length 

of the quadrant roadway, the number of lanes and left-turn storage provided on the quadrant 

roadway, and the assumed cycle length. Shorter quadrant roadways (less than 800 ft) will 

require greater attention to queue lengths and storage requirements to ensure there is no 

spillback between the two secondary T-intersections. 

Note that queuing between the secondary T-intersection and main intersection is typically not 

critical because the signal phasing is set to progress and not store queues between the two 

intersections. This is described in greater detail in chapter 5.

INCIDENT RESPONSE CONSIDERATIONS

Direct left turns at QR intersections are denied by signing, signal indications, and pavement 

markings. However, emergency vehicles using sirens and flashing lights as they approach a QR 

intersection can make a direct left turn after vehicles with conflicting movements have yielded 

the ROW. This practice is no different than an emergency vehicle making a direct left turn at a 

conventional intersection when approaching a red signal indication. As noted earlier, QR 

intersections have 20 fewer conflict points at the main intersection compared a conventional 

intersection. As a result, emergency vehicles traveling through the QR intersection have fewer 

potential conflict points with vehicles who must yield right of way.

One issue that may arise related to emergency vehicles is whether or not the quadrant roadway 

should have its own street name and address number. Having a street number is necessary for 

efficient emergency vehicle response; however, naming the quadrant roadway complicates 

signing and wayfinding for motorists using the roadway as part of a left-turn movement. The 

preferred practice is to name the quadrant roadway only if the land parcels are not accessible 

from either roadway (are ONLY accessible via the quadrant roadway).

OBSERVED SAFETY PERFORMANCE

There is little published crash data and documented safety performance for existing QR 

intersections. There has also not yet been a noteworthy study of crash experience at QR 

intersections, and no crash data involving pedestrians or bicyclists at QR intersections have been 

collected or analyzed. This section presents and discusses limited empirical safety data for QR 

intersections in the U.S.

Crash Observations

Since the publication of the FHWA QR Intersection Tech Brief in 2010, there have been three 

QR intersections constructed—Fairfield, Ohio; Huntersville, North Carolina; and Front Royal, 

Virginia. The Fairfield and Huntersville intersections both opened in 2012; thus, there has been 

sufficient time to acquire meaningful “after” crash data to perform full before-and-after safety 

studies. The Fairfield QR intersection is located at the main intersection of SR-4 and SR-4 

Bypass, and the quadrant roadway was named “Diversion Road”. The Huntersville QR 

intersection is located at the main intersection of NC-73 and US-21, and the quadrant roadway 

repurposed an existing roadway (Holly Point Drive) in the southeast intersection quadrant.
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 4: SAFETY 

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At both the Fairfield and Huntersville QR intersections, before-and-after safety studies have been 

conducted by their governing transportation agencies that include three years of crash data 

collected from before and after the QR intersection was opened. However, this is a naïve analysis 

that does not account for effects of changing traffic volume or non-site specific trends that may 

influence crashes in the respective communities. 

Table 6 summarizes the results of the before-and-after safety study conducted for the Fairfield 

QR intersection.(22) Comparative analysis results show that crashes at the main intersection and 

the SR-4 / Diversion Road T-intersection were reduced in number and severity compared to the 

prior conventional intersection. However, there were a significant number of crashes, many 

resulting in injuries, at the SR-4 Bypass / Diversion Road intersection, bringing the threeintersection total to be greater than the “before” singular conventional intersection. Further 

evaluation of the crash data showed the clear majority of the SR-4 Bypass / Diversion Road 

crashes were rear-end crashes (72 percent), and further engineering studies are on-going to 

determine if signal timing, driver confusion or other causes are the root of the high crash 

frequency at this T-intersection. 

Table 6. Three-year crash data comparison at Fairfield QR intersection. 

Note: Pre-project data collected Nov 2006 to Nov 2009; Post-project data collected for 3-year period from August 

2007 to July 2010. 

Table 7 summarizes the results of the before-and-after safety study conducted for the 

Huntersville QR intersection.(23) Comparative analysis results show that total crashes and frontal 

impact (higher severity) crashes were increased at two of the three intersections, with reductions 

only at the NC-73 / Holly Point intersection. However, the total crash severity index increased by 

only 1 percent (from 3.09 to 3.12). Also, the average intersection volume increased by 10,000 

vpd (an 18 percent increase) in the years between the before-and-after crash study periods. 

Factoring the crashes per million-vehicles entering the intersection, the crash rates before was 

2.24 per million vehicles and after was 2.44 per million vehicles (a 9-percent increase). 

Crash Type

Pre-Project 

SR-4 / SR-4 

Bypass 

Post-Project 

SR-4 / SR-4 

Bypass

Post-Project 

SR-4 / 

Diversion Rd

Post-Project 

SR-4 Bypass / 

Diversion Rd

Post-Project 

Totals (3 

Intersections)

Post-Project 

Total 

Change 

Total 

Crashes 77 55 10 90 155 +102% 

Injury Crash 30 15 2 23 40 +33% 

Injuries 45 19 3 37 59 +31% 

Fatal 0 0 0 0 0 no change 

Serious 

Injury 2 0 1 1 2 no change 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 4: SAFETY

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Table 7. Three-year crash data comparison at Huntersville QR intersection.

Crash Types

Before

NC-73 /

US-21

Before

NC-73 / 

Holly Pt.

Before

US-21 / 

Holly Pt.

Totals

After

NC-73 /

US-21

After

NC-73 / 

Holly Pt.

After

US-21 / 

Holly Pt.

Totals Total 

Change

Total Crashes 65 35 13 203 81 28 36 265 +31%

Severity Index - - - 3.09 - - - 3.12 +1%

Fatal/Class A 

Injury Crashes - - - 1 - - - 0 -100%

Front Impact 

Crashes 10 23 9 42 22 5 21 48 +14%

Rear End 

Crashes 47 11 4 62 47 17 11 65 +5%

Note: Pre-project data collected Nov 2006 to Nov 2009; post-project data collected July 2012 to July 2015. –

Signifies no data available.

Table 8 summarizes the results of the before-and-after safety study conducted for the Front 

Royal intersection.

(24) The crash study area included the same roadway segment lengths upstream 

and downstream from the main intersection, with and without the additional QR T-intersections.

Note that since the Front Royal QR intersection has been open for only 18 months, only one year 

of crash data was available to be compared to three years of the conventional intersection prior to

the QR intersection project. Therefore, results from this study should be regarded with caution.

Comparative analysis results show that total crashes increased by 25 percent, but injury crashes 

and injuries were reduced by 130 and 230 percent, respectively. Property-damage-only (PDO) 

crashes and costs increased by 48 and 23 percent, respectively. 

Table 8. One-year crash data comparison at Front Royal QR intersection.

Crash Types

2011

Crash 

Data 

2012 

Crash 

Data

2013 

Crash 

Data

3-Year 

Total

2011-

2013 Avg

2018 

Crash 

Data

Percent 

Change

Total Crashes 5 7 6 18 6.0 8 +25%

Rear End Crashes 5 7 6 18 6.0 5 -20%

Angle Crashes 0 0 0 0 0.0 1 +100%

Sideswipe (same direction) 0 0 0 0 0.0 2 +200%

Injury Crashes 3 2 2 7 2.3 1 -130%

Persons Injured 5 2 3 10 3.3 1 -230%

PDO Crashes 2 5 4 11 3.7 7 +48%

PDO Costs $31,300 $24,800 $21,000 $77,200 $25,733 $33,400 +23%

Note: Three-year pre-project data collected Jan 2011 to Dec 2013; One-year post-project data collected Jan to Dec 2018.
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 4: SAFETY 

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SUMMARY OF SAFETY EVALUATION CONSIDERATIONS 

Due to the limited number of QR intersections that have been open for a sufficient time to gather 

meaningful post-installation crash data, there are not yet CMFs specific to QR intersections. If 

agencies wish to construct their own before-and-after safety evaluation of a set of QR

intersection projects, there are several factors to keep in mind, including: 

• The boundaries of the analysis area need to be large enough to include all three QR 

intersections. It would be unfair to compare a conventional intersection to just the main 

intersection of a QR intersection. 

• Left-turn vehicles at a QR intersection drive longer distances to negotiate the quadrant 

roadway compared to conventional intersections. Thus, any analyses using rates, such as 

crashes per vehicle-mile, must consider the “extra” distances driven.

• It is possible that some left-turning drivers may alter their routes to avoid the intersection or 

use patterns outside of the QR, if available, or through vehicles may divert to the 

uncongested quadrant roadway. Thus, crash migration should be given due consideration. 

Analysts should measure traffic demands during the before and after periods, and if crash 

migration is suspected should also widen the scope of analysis to include new routes drivers 

are using. 

• QR intersections may be installed in conjunction with developments that generate traffic. 

This reinforces the need to account for volume in an analysis since higher volumes result in 

more predicted crashes and lower crash rates for the same number of crashes. Methods such 

as empirical Bayes analysis, described in the Highway Safety Manual,

(12)

 are able to 

explicitly handle changes in traffic volumes. 

General guidance on before-and-after safety studies and development of CMFs can be found in 

FHWA’s A Guide to Developing Quality Crash Modification Factors.

(25) 
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CHAPTER 5 — OPERATIONAL CHARACTERISTICS 

This chapter provides information on the unique operational characteristics of QR intersections 

and how they affect elements such as traffic signal phasing and coordination. The guidance 

presented here builds on existing QR intersection studies, which include operational performance 

studies, comparative performance studies, and simulation analysis. The chapter also provides 

guidance relating to design elements that could affect the operational performance of QR 

intersections. It is intended to help transportation professionals understand the unique operational 

characteristics of QR intersections and prepare them for conducting operational analysis as 

described in chapter 6. 

Figure 58 compares D Street left-turn movements made at a conventional intersection versus a 

QR intersection. Figure 59 compares A Street left-turn movements made at a conventional 

intersection versus a QR intersection. 

© NCDOT 

Figure 58. Graphic. Conventional versus QR left turn movements: D Street. 

© NCDOT 

Figure 59. Graphic. Conventional versus QR left turn: A Street. 
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OPERATIONAL CONSIDERATIONS 

The QR intersection provides traffic operational benefits, particularly for through movements, by 

reducing the number of intersection signal phases at the main intersection and shortening 

intersection signal cycle lengths. Despite several turning patterns requiring vehicles to travel an 

additional distance compared to a conventional intersection, QR intersection left turns typically 

have equal or improved travel times. However, there are many operational considerations that 

can diminish or enhance QR intersection operational performances. 

Location of the Quadrant Roadway Based on Volume Characteristics 

Each of the four QR intersection left-turn movements illustrated in figure 58 and figure 59 can 

have significantly different impacts on operations depending on intersection volumes. Using the 

movement abbreviations developed in chapter 4, some interesting operational characteristics can 

be noted: 

• The QL-QL movement is completely removed from impacting the main intersection. 

Therefore, the best quadrant arrangement from a capacity and operations perspective would 

link this movement with the highest intersection left-turn demand. Note that the 

complementary right turn may also be heavy and would likewise completely avoid the main 

intersection. 

• Movements that end with MT re-route vehicles into an “interior” approach to the main 

intersection, potentially creating queuing challenges for signal coordination. 

• The MT-QR-QR-MT movement potentially impacts the capacity of the main intersection 

twice (depending on critical movements). 

Location of the Quadrant Roadway Based on Land Use and Access Impacts 

When planning a QR intersection to improve operations at a conventional intersection, one of the 

first considerations is in which intersection quadrant to place the quadrant roadway. In most 

cases, this decision is limited to (or dictated by) the availability of land in a singular intersection 

quadrant or the presence of an existing roadway that can be repurposed. Since QR intersections 

are best suited at the crossing of two major roadways, typically one or more (and often all) of the 

intersection quadrants are often already developed, often limiting the choice of a vacant parcel (if 

any) and most intersections lack an existing roadway that can be suitably repurposed as a 

quadrant roadway. 

In the case that there is land available in two or more quadrants, future operations can be 

modeled for each option available using planning-level tools (such as FHWA’s Capacity 

Analysis for Planning of Junctions [CAP-X] tool) to gain a general understanding of intersection 

capacity, geometric requirements and expected intersection operations. However, because of the 

interdependency of the three traffic signals in a QR intersection, detailed operational analysis 

requires the use of microscopic simulation tools to answer detailed questions such as total travel 

time of individual left-turn patterns before and after a QR intersection improvement. 

The QR intersection has varying access impacts in each of the four intersection quadrants, as 

illustrated in figure 60. The intersection quadrant containing the quadrant roadway has 

potentially the best access, as property (or properties) on the outside of the quadrant roadway 

could have access to both intersecting roadways via the quadrant roadway and the area inscribed 

by the quadrant roadway has access to both signalized intersections (via the quadrant roadway) 

plus potential RIRO access to both roadways. 
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 NCDOT

Figure 60. Graphic. QR intersection access impacts.

The two quadrants opposite the quadrant roadway have potential access impacts. While 

landowners and developers would see immediate potential for access to either intersection 

roadway (by adding a driveway as a fourth leg to the T-intersection signal), the overall efficiency 

of the QR intersection depends on the signal phasing afforded by the T-intersection. Therefore, 

every effort should be made to preserve the T-intersection functionality and limit access 

between signalized intersections to right-in/right-out access. Lastly, the intersection quadrant 

diagonally opposite from the quadrant roadway may have perceived access impacts due to the 

loss of direct left turns at the main intersection, but efficiency gains by the QR intersection 

should offset any perceived impacts to access to this quadrant.
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Access Management 

Access management is an important factor to consider in QR intersection safety. QR 

intersections are best suited for urban and suburban areas where there is often auto-dependent 

development in one or more intersection quadrant(s) that depend on good access to both 

intersecting roadways. 

Potential access management issues that could impact intersection operations and safety include: 

• Allowing a fourth leg at one or both secondary T-intersections with managed access. The 

Huntersville, North Carolina partial-QR intersection allows a fourth leg at the NC-73 / 

quadrant roadway intersection to provide access to a regional shopping center opposite the 

quadrant roadway. Access to the fourth leg is managed by a RCUT intersection design that 

permits left turns from NC-73 but restricts left turns from the fourth leg, lessening 

intersection operational and safety impacts of a full-movement intersection. 

• Relocating an existing roadway that would otherwise add an additional leg to the secondary 

T-intersection (or worse, intersect the roadway in between the main and secondary Tintersections). The Front Royal, Virginia QR intersection included the relocation of an 

existing residential street to intersect one of the roadways at a full-movement intersection 

upstream of the secondary-T intersection. 

While access management needs and issues will be different for each site, there are several 

principles that will help the QR intersection function optimally: 

• At a minimum, a raised median should be placed between the crossing and secondary Tintersections on BOTH roadways. This access control will limit delays and unexpected 

vehicle conflicts between the closely spaced intersections. Right-in/right-out access may be 

provided between these intersections so long as the impacts do not degrade traffic on the 

through roadways. 

• A raised median is highly recommended along the length of the quadrant roadway between 

secondary T-intersection to limit future full access to the quadrant roadway. If access to the 

quadrant roadway is required to serve existing development and can be safely managed, a 

singular mid-point access may be provided and ideally managed with a directional median 

opening. If there are multiple land uses within the quadrant roadway, the driveways should 

be consolidated to a single access point on the quadrant roadway.

• With both of the first two access management principles in place, the land parcel inscribed 

by the quadrant roadway is limited to right-in/right out access on one or more roadways, 

and this may present challenges to access depending on the land use within the quadrant. 

Allowing U-turns on any of the intersection approaches should be avoided, particularly 

where no dedicated left / U-turn lane is provided. 

Figure 61 illustrates access management principles where land uses within the quadrant can be 

served by a RIRO access on the quadrant roadway. Figure 62 illustrates access management 

principles where directional median access to the area inscribed by the QR is provided from the 

quadrant roadway. 
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73

 © NCDOT 

Figure 61. Graphic. QR RIRO access management recommendations. 

 © NCDOT 

Figure 62. Graphic. QR directional access management recommendations. 
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The level of access management on the quadrant roadway has impacts on the accessibility to 

land uses within the quadrant roadway. Figure 63 and figure 64 illustrate vehicle paths 

approaching the QR intersection from all four directions and shows the paths of both pass-by 

traffic and traffic destined for land uses internal to the quadrant roadway and then returning to 

their ordinal direction. Figure 63 shows vehicle paths assuming RIRO access to the quadrant and 

figure 64 shows vehicle paths assuming a directional median break on the quadrant roadway. 

The RIRO access condition requires provision of three different U-turn movements and creates a 

circuitous return path for vehicles to/from the north (under this quadrant roadway location). 

Providing a directional median opening on the quadrant roadway eliminates one U-turn 

movement at the secondary T-intersection. Note that the routing patterns assume that there is 

internal circulation within the inscribed intersection quadrant that connects the access points. 

© NCDOT 

Figure 63. Graphic. Directional vehicle paths w/RIRO access on quadrant roadway. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 5: OPERATIONAL CHARACTERISTCS 

75

© NCDOT 

Figure 64. Graphic. Directional vehicle paths w/directional access on quadrant roadway. 

Spacing of Secondary T-Intersections 

The spacing of the two secondary T-intersections have significant impact on both intersection 

operations and motorist acceptance of the QR intersection. Secondary T-intersections placed too 

close to the main intersection may cause a queue spillback from the left-turn lane onto the 

quadrant roadway. Secondary T-intersections placed too far from the main intersection increases 

the added distance left turns must travel, which may be untenable to motorists and cause them to 

seek other paths via parallel roads and/or through surface parking to cut through and bypass the 

main intersection. Note that QR intersection geometry does not have to be symmetrical; the 

crossing and two secondary T-intersections may have unequal spacing. 

As noted in chapter 4, crossing and secondary T-intersections spaced too close together may 

create safety and operational issues. Of equal concern is crossing and secondary T-intersection 

spacing that is too far apart. For most QR intersection left-turn movements, motorists are 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 5: OPERATIONAL CHARACTERISTCS 

76

traveling greater distances to make a left-turn compared to a conventional intersection. Figure 65

illustrates the additional travel distance incurred by left-turn movements at QR intersections 

assuming equal 500-ft intersection spacing. Two left-turn movements incur an additional 850 ft 

in travel distance, with the longest left turn path (A to D) requiring an additional 1,850 ft travel 

distance. Figure 66 illustrates the additional travel distance incurred by left turn movements at 

QR intersections assuming equal 800-ft intersection spacing. At this spacing, two left-turn 

movements incur an additional 1,320 ft in travel distance, with the longest left turn path (A to D) 

requiring an additional 2,920 ft travel distance (more than 0.5 mi). At an average travel speed of 

30 mph, the 2,920 ft travel distance equates to 70 seconds of travel time, which may exceed 

delays waiting for a left-turn phase at a conventional signalized intersection. 

 © NCDOT 

Figure 65. Graphic. Additional QR left-turn travel distances at 500-ft spacing. 

© NCDOT 

Figure 66. Graphic. Additional QR left-turn travel distances at 800-ft spacing. 
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Table 9 through table 13 provide the travel distances for QR roadway left turns compared to left 

turns at a conventional intersection based on different intersection spacings on Street A-B and 

Street C-D, assuming the quadrant roadway is located in intersection quadrant B-C.

Table 9. Additional QR left-turn travel distances: Street C-D spacing = 400 ft. 

Table 10. Additional QR left-turn travel distances: Street C-D spacing = 500 ft.

Table 11. Additional QR left-turn travel distances: Street C-D spacing = 600 ft.

Table 12. Additional QR left-turn travel distances: Street C-D spacing = 700 ft.

Table 13. Additional QR left-turn travel distances: Street C-D spacing = 800 ft.

Left Turn 

Street A-B

Spacing 400 ft

Street A-B

Spacing 500 ft

Street A-B

Spacing 600 ft

Street A-B

Spacing 700 ft

Street A-B

Spacing 800 ft

A to D 1,490 1,690 1,890 2,090 2,290

B to C -110 -110 -110 -110 -110

C to A 690 690 690 690 690

D to B 690 890 1,090 1,290 1,490

Totals 2,760 3,160 3,560 3,960 4,360

Left Turn 

Street A-B

Spacing 400 ft

Street A-B

Spacing 500 ft

Street A-B

Spacing 600 ft

Street A-B

Spacing 700 ft

Street A-B

Spacing 800 ft

A to D 1,690 1,850 2,050 2,250 2,450

B to C -110 -150 -150 -150 -150

C to A 890 850 850 850 850

D to B 690 850 1,050 1,250 1,450

Totals 3,160 3,400 3,800 4,200 4,600

Left Turn 

Street A-B

Spacing 400 ft

Street A-B

Spacing 500 ft

Street A-B

Spacing 600 ft

Street A-B

Spacing 700 ft

Street A-B

Spacing 800 ft

A to D 1,890 2,050 2,210 2,410 2,610

B to C -110 -150 -190 -190 -190

C to A 1,090 1,050 1,010 1,010 1,010

D to B 690 850 1,010 1,210 1,410

Totals 3,560 3,800 4,040 4,440 4,840

Left Turn 

Street A-B

Spacing 400 ft

Street A-B

Spacing 500 ft

Street A-B

Spacing 600 ft

Street A-B

Spacing 700 ft

Street A-B

Spacing 800 ft

A to D 2,090 2,250 2,410 2,560 2,760

B to C -110 -150 -190 -240 -240

C to A 1,290 1,250 1,210 1,160 1,160

D to B 690 850 1,010 1,160 1,360

Totals 3,960 4,200 4,440 4,640 5,040

Left Turn 

Street A-B

Spacing 400 ft

Street A-B

Spacing 500 ft

Street A-B

Spacing 600 ft

Street A-B

Spacing 700 ft

Street A-B

Spacing 800 ft

A to D 2,290 2,450 2,610 2,760 2,920

B to C -110 -150 -190 -240 -280

C to A 1,490 1,450 1,410 1,360 1,320

D to B 690 850 1,010 1,160 1,320

Totals 4,360 4,600 4,840 5,040 5,280
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While there is no hard rule for maximum intersection spacing, planners and designers should be 

acutely aware of the left-turn distance and travel time penalties imposed by greater intersection 

spacing, particularly when other travel path alternatives exist (even circuitous cut-through or 

paths through parking lots) that may tempt motorists to avoid using the prescribed QR 

intersection turning paths. 

Left-Turn Storage 

Minimum intersection spacing can also be governed by the needed distance for left-turn storage 

between the main intersection and downstream secondary T-intersection. The length of left-turn 

storage bays should be determined thorough HCM analyses or microsimulation study, but as a 

rule of thumb, the left-turn storage lane should be designed to accommodate 1.5 to 2 times the 

average vehicle queues per cycle. AASHTO guidance calls for a taper rate of between 8:1 to 

15:1 for high-speed roadways. Table 14 summarizes a suggested minimum distance (to 

accommodate adequate storage plus taper) between the crossing and secondary T-intersections 

based on levels of left-turn volumes and 90- and 120-second cycle lengths. 

Table 14. Storage bay and taper length guidance. 

Left Turns 

(vph) 

Storage + taper length 

(90-second cycle) 

Storage + taper length 

(120-second cycle) 

100 190 - 230 230 - 270

150 240 - 290 290 - 350

200 290 - 350 350 - 430

250 330 - 410 410 - 520

300 380 - 480 480 - 600

350 430 - 540 540 - 680

400 480 - 600 600 - 770

Note: Assumes single turn lane, average car length of 25 ft and 

minimum taper ratio of 8:1 (100 ft for 12-ft lanes). 

Table 14 values support an assumption that intersection spacing of approximately 500 ft should 

provide adequate intersection storage, with greater storage needed in cases of high left-turn 

volumes (more than 300 vph) and/or moderate left-turn volumes and longer cycle lengths (120 

seconds and greater). Note that these values are provided to serve as a planning-level guide for 

minimum intersection spacing. Governing State or jurisdictional policies for storage length 

and/or taper lengths should be investigated and followed. 

Simulation studies have shown that at intersections with moderate to low left-turn demand (300 

vph or less) and a cycle length of 120 seconds or less, a left-turn bay and taper of 300 and 150 ft, 

respectively (resulting in an overall intersection spacing of approximately 500 ft), will provide 

adequate queue storage at a 95-percent confidence level.(1) However, it is always appropriate to 

use HCM and/or microsimulation analysis to verify storage lengths required with known 

intersection volumes and signal timings. 

Coordination with Mobile Navigation Systems 

During the final stages of the project, the project team or jurisdictional authority should consider 

contacting the large providers of mobile navigation data to ensure that the coding of the QR 

intersection (including turn prohibitions) is current when the project opens in order to avoid 
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79

confusion or incorrect movements. In the case of the SR-4 / SR-4 Bypass, the right-turning 

movement was not coded correctly, and instead of a simple right-turn movement at the main 

intersection, motorist on northbound SR-4 were directed to travel through the main intersection, 

turn right onto the quadrant roadway and then left at the secondary T-intersection. Once this was 

conveyed to the project manager, a request was made to fix the coding of this intersection. 

SIGNAL CYCLE LENGTHS, PHASING AND COORDINATION 

Cycle Length 

The QR intersection, like many other alternative intersections, removes left-turn phasing at the 

main intersection, which results in a reduction in the number of clearance phases in each signal 

cycle from four to two compared to a conventional intersection. The time formerly allocated for 

the eliminated clearance intervals can be reallocated to through and right-turn movements at the 

main intersection that results in greater intersection efficiency. The elimination of clearance 

phases and reduction in signal phases can also allow the cycle length to be shortened, as only two 

phases and two clearance times are served in the signal cycle. The left-turn clearance phases are 

typically longer than through movement clearance times and are removed from the signal cycle. 

Shorter cycle lengths allow more cycles to be served each hour, and vehicles have less time to 

“store” and form queues, thus shortening queues. However, desirable short cycle lengths are 

often infeasible for conventional intersections with multi-phase signals required to serve all 

approach demands. 

Figure 67 illustrates a 150-second conventional intersection multi-phase signal that serves 

protected through and separate left-turn movements from both intersecting roadways, separated 

by intersection clearance phases. Figure 68 illustrates a 90-second QR main intersection twophase signal that serves through and right-turn movements from both intersecting roadways, 

separated by intersection clearance phases. Figure 69 illustrates a 90-second QR secondary Tintersection that serves the through street and turns to/from the quadrant roadway. Under the QR 

intersection, the percentage of the signal cycle allocated to through and right-turn movements is 

significantly increased by the elimination of left-turn and clearance phases and more cycles can 

be served each hour. 

 © NCDOT 

Figure 67. Graphic. 150-second conventional intersection multi-phase signal splits.
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80

 © NCDOT. 

Figure 68. Graphic. 90-second QR main intersection signal splits. 

 © NCDOT. 

Figure 69. Graphic. 90-second QR secondary-T intersection signal splits. 

Comparing these figures, the green time allotted to the arterial through movement is 56 seconds 

under a conventional intersection and 45 seconds under a QR intersection. The conventional 

intersection 150-second cycle serves 24 full cycles each hour, which allocates 1,344 seconds of 

green time to the arterial through movement. The QR intersection’s 90-second cycle serves 40 

full cycles each hour, which allocates 1,800 seconds of green time to the arterial through 

movement. Figure 70 illustrates this comparative 34-percent increase in green time provided 

under the 90-second two-phase signal at a QR intersection compared to the 150-second multiphase signal at a conventional intersection. However, since left-turn movements pass through the 

intersection as well (some twice), the actual net increase in capacity is likely to be somewhat less 

than 34 percent. 
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81

© NCDOT 

Figure 70. Chart. Comparison of movement green times. 

To achieve optimal QR intersection operations and signal coordination, each of the 3 signalized 

intersections within the QR intersection must have the same cycle length, which typically ranges 

from 90 to 120 seconds. The cycle length is dependent on intersection traffic volumes, pedestrian 

crossing times, and the cycle lengths of other adjacent signals on the corridors upstream and 

downstream of the QR intersection. In some cases, a QR intersection will operate well with a 

shorter cycle length than is appropriate for one or more of the other signalized intersections 

along a corridor. If the cycle length for the QR intersections is half of the cycle length for 

upstream and downstream signals in the network, signal coordination and progression can 

remain along the corridor while also maintaining the benefits of QR intersection. In other cases, 

the cycle length of the corridor signals may be decreased to match the QR intersection cycle 

length. If the most congested intersection on a corridor is converted to a QR intersection, 

decreasing the cycle length may benefit intersections for the whole corridor.

Signal Phasing 

The QR intersection allows two-phase signal operations at the main intersection, but the 

secondary T-intersections include three signal phases. Figure 71 illustrates the phasing at the 

crossing and secondary T-intersections. The main intersection operates under a two-phase signal 

for both vehicles and pedestrians. This simple signal phasing is both efficient for vehicles and 

allows sufficient crossing time for pedestrians. The secondary T-intersections require three 

separate phases to serve the main or crossing street through movements, left turns from the main 

or crossing street onto the quadrant roadway and left and right turns leaving the quadrant 

roadway. However, signal phasing and coordination strategies can be employed so that traffic on 

the main and crossing roadways experience the efficiency of two-phase signal operations. 
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 © NCDOT

Figure 71. Graphic. QR intersection signal phasing.

Signal Coordination and Offsets 

The removal of left turns at the main intersection results in greater green bandwidths and greater 

progression opportunities through both the main and secondary T-intersections. If the signal 

phasing and offsets are properly coordinated, through traffic may be required to stop only at the 

first signal (either the main or secondary T-intersection depending on approach direction) or 

travel through BOTH intersections without stopping. As a general rule, through vehicles that 

stop for the first intersection should always arrive on green at the second intersection; therefore, 

all through vehicles should stop no more than once.

Figure 72 illustrates the spatial time-space diagram (TSD) relationship between the three QR 

intersection signals. In order for to achieve consistent coordination between the signals, all three 

intersections must have the same cycle length. In the TSD below, the common cycle length is 

assumed to be 90 seconds. Equal phase splits were assumed at the two-phase main intersection 

(40 seconds green plus 5 second yellow/all-red [Y/AR] phase for each direction), and roughly 

equal left-turn phases were assumed at both secondary T-intersections (22 or 23 seconds green 

plus 5 seconds Y/AR for each left-turn phase). 
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© NCDOT 

Figure 72. Graphic. QR intersection time-space diagram.

Beginning with the eastbound through phase at the D Street T-intersection (1), vehicles leave this 

intersection traveling 500 ft at the 45-mph roadway design speed would arrive approximately 8 

seconds later at the main intersection, just as the signal turns green. Conversely, westbound 

vehicles starting from the main intersection (2) arrive approximately 8 seconds later at the 

secondary T-intersection while the signal is already green. 

When the eastbound secondary T-intersection green phase ends, progression should allow the 

last eastbound vehicles to proceed through the main intersection. When this phase ends (3), a 

lagging left-turn phase can begin in the westbound direction, allowing queued left-turning 

vehicles in the westbound direction to turn left onto the quadrant roadway. This through-left 

phase lasts as long as needed to clear the left-turn queue, also allowing sufficient time for the last 

of the westbound through vehicles to clear the secondary T-intersection (4). The remainder of the 

cycle length at the secondary T-intersection can be allotted to serve the left turns departing the 

quadrant roadway. 
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Nearly the same cycle pattern repeats itself for A Street; however, the left turn onto the quadrant 

roadway is a leading left, taking advantage of the delayed arrival of the southbound A Street

through vehicles. The leading left begins exclusive and transitions to a shared through-left phase 

at the time when the through vehicles can progress to arrive at the main intersection at the 

beginning of green.

Note that the phasing and coordination presented is a simplified condition given that two of the 

four left-turn movements removed from the main intersection are routed back through the main 

intersection as part of the through movement. As a result, there may be standing queues on the 

“internal” main intersection approaches when those approaches receive green. Depending on the

level of volumes entering these two approaches while the signal is red, the initial greens could be 

occupied for several seconds to start-up and clear these waiting queues. The best way to account 

for the variances in intersection spacing, cycle lengths, design speeds and internal left-turn 

queuing would be to prepare a site-specific TSD for each unique QR intersection installation, 

further study coordination and progression using microsimulation tools, and make slight field 

adjustments according to actual operational conditions when the project opens.

The spatial TSD also shows how two of the left-turn movements arrive at the secondary Tintersections. The travel speeds are adjusted to reflect the lower speed of the quadrant roadway

and the longer distance between signals along the quadrant roadway (in this case nearly 900 ft). 

Figure 72 illustrates that left turns leaving the A Street T-intersection traveling the quadrant 

roadway counterclockwise would arrive a few seconds before the left-turn phase exiting the 

quadrant roadway begins. However, left turns leaving the main street secondary T-intersection 

arrive at the downstream signal squarely within a red phase. Knowing the arrival patterns may be 

a factor in designing appropriate storage capacity, in this case for right turns onto southbound A

Street.

THROUGHPUT AND FLOW RATES

Corridor Throughput

The combination of reduced clearance intervals and reduced cycle lengths with QR intersections 

enables greater corridor throughput compared to a conventional intersection. However, QR 

intersections are typically isolated solutions to improve operations at singular intersections with 

significant volumes on both intersecting roadways. Thus, QR intersections do not necessarily 

improve corridor operations and throughput unless the intersection has the significantly worst 

operational performance along a corridor. 

QR intersections gain throughput efficiency due to the two-phase signal operations at the main 

intersection. With only two phases, the amount of intersection lost time is reduced due to fewer 

yellow and all-red clearance phases compared to a conventional intersection. Note that the QR 

having full signals and spacing is critical to good corridor efficiency.

Lane Utilization

For two approaches to a QR intersection (where left turns are made from the left side of the 

roadway), lane utilization would be very similar to that of a conventional intersection with the 

same number and configuration of through and turn lanes. However, the other two approaches, 

where both left and right turns are made from the right side of the roadway, the rightmost lanes 

will likely have higher utilization. Consideration should be given to multiple right-turn lanes (or 

shared through/right-turn lanes) where volumes may overload a single right-turn lane. Also, 

right-turn storage lanes may have to be lengthened in anticipation of additional vehicle storage.

Figure 73 illustrates this proposed geometry.
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© NCDOT

Figure 73. Graphic. Lane continuity through QR left-turn movement. 

Systemwide Considerations 

Unlike corridor-based alternative intersection treatments like the RCUT, QR intersections are 

suitable for and typically used at a singular intersection where volumes on both roadways are 

significant and fairly balanced; thus, the QR intersection is more likely to compete with 

multilane roundabouts, displaced left-turn (DLT) intersections, and MUT intersection 

alternatives. The use of multiple QR intersections in a corridor is not discouraged, but there 

would likely be little operational gains to the corridor and finding successive intersections with 

vacant quadrants or viable roadways to repurpose for quadrant roadways may be challenging. All 

known QR intersections constructed to date have been at isolated intersection locations.

COMPARATIVE PERFORMANCE STUDIES AND LITERATURE REVIEWS 

Based on the comparative traffic operations and simulation studies summarized in table 15, QR 

intersections had the following operational advantages compared to conventional designs: 

• Significantly reduced intersection queuing. 

• Increased throughput of 5 to 15 percent. 

• Reduced intersection delay by 20 to 50 percent. 

• Consistently high-performing intersection form under varying geometric and volume 

conditions. 
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Table 15. Summary of comparison literature and performance studies. 

Study Authors, 

Publication & Date 

Type of 

Study Key Finding 

Reid, ITE Journal 2000(1) Simulation 

Reduced average cycle length by 58 percent; Reduced system 

travel time by 15 percent and reduced delay by 46 percent; 

Greatly improved intersection queue lengths, with the longest 

queue lengths averaging 88-percent shorter compared to the 

conventional design. 

Reid and Hummer, TRB 

2001(3) Simulation 

In comparison of different alternative intersections types 

over a variety of intersections, the quadrant roadway and 

median U-turn designs usually vied for the lowest average 

total time. 

FHWA 2010 Alternative 

Intersection & Interchange 

Report (AIIR)(13)

Simulation 

Higher throughput/lower travel times for scenarios with 

heavy through and moderate left-turn volumes on the main 

street and heavy through and left-turn volumes on the cross 

street. 

FHWA Tech Brief 2009(14) Simulation 

QR throughput showed a 5- to 15-percent increase in travel 

time and a 5- to 20-percent reduction in travel time 

compared to conventional intersections. 

Reese, Carrol & Epperson 

2014(3) Field 

40-percent reduction in intersection delay; significant 

reduction in intersection queues. 

Results from 2000 ITE Study

Both the conventional and QR intersection traffic analysis models used the same coordinate and 

node system to allow equitable comparison of the system-wide MOEs using CORSIM. Signal 

timing designs for both the conventional and QR intersection design were optimized in Synchro. 

The simulation experiment included various levels of traffic volumes and splits: 

• Level of Service (LOS) C and E intersection volumes. 

• Both 55 and 70 percent roadway volume splits to represent balanced and more dominant 

traffic on the major street. 

• Both 50 and 65 percent directional splits, representing balanced and directional traffic.

• Both 10 and 15 percent turn movements (applied equally to right and left turns), 

representing moderate and heavy left-turn volumes. 

Signal and intersection geometric characteristics included: 

• All QR intersections assumed protected-only left-turn phasing; the conventional design 

included fully-actuated signal control. 

• The conventional intersections assumed dual left-turn lanes on the major street and single 

left-turn lanes on the minor street. 

The factorial experiment included 64 simulation runs analyzing LOS conditions, volume splits, 

directional splits, and turn-movement percentages consistent for both conventional and QR 

intersections. System travel-time and delay times were measured in CORSIM by vehicle-hours 

and average speed. Stops per vehicle and maximum queues were computed for each link in the 
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network. Through and left turn travel times were examined for specific links. Intersection LOS 

and delay were computed from CORSIM results and post-processed to HCM standards. The 

MOE results for conventional and QR alternatives from the study are summarized in table 16. 

Table 16. Summary of ITE study results. 

Analysis results show the QR intersection had a 15-percent reduction in system travel time and a 

46-percent reduction in system delay. The reduction in system delay is greater because QR leftturn travel distances are greater, but vehicles are in motion (not counted as delay) along the 

quadrant roadway. The QR intersection was shown to be considerably more efficient for through 

travel time, with a 30-percent reduction in through movement travel time. However, left-turn

travel time was increased by 4 percent. The improvement in through-movement travel time 

greatly influenced overall intersection delay, which was reduced by 215 percent at the main 

intersection, and an improvement on average from LOS E to LOS B. The QR intersection also 

significantly reduced intersection queue lengths, with the longest queue lengths averaging 41-

percent shorter compared to the conventional design.

Results from 2001 TRB Study

Seven different alternative intersections (including the QR intersection) were compared to a 

conventional intersection based on actual intersection volumes and characteristics. The authors 

obtained turning movement counts for seven existing, high-volume intersections in Virginia and 

North Carolina. Table 17 provides details on the selected intersections, including the number of 

lanes, roadway ADT volumes, and average percent turning movements.

Measure Conventional QR Intersection Percent

Difference

Cycle Length 142.0 90.0 - 58%

System Delay, veh/h 35.8 24.4 - 46%

System Travel Time, veh-h 66.9 58.2 - 15%

Stops per vehicle 0.71 0.78 + 9%

Speed, mph 23.4 27.2 + 14 %

Maximum queue, veh 23.4 12.4 - 47%

WB Left Travel Time, sec/veh 120.9 125.6 + 4%

EB Left Travel Time, sec/veh 86.6 66.5 - 30%

Main intersection delay, sec/veh 41.2 13.5 - 215%

Main intersection LOS E B N/R
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Table 17. TRB study intersection evaluated. 

Intersecting 

Roads Location 

Lanes 

(Main/ 

Cross) 

Percent 

Main 

Green 

Percent 

Turns 

Roadway ADT 

(Main/Cross) a

Intersection 

ADT a

Fairview Rd/ 

Sharon Rd Charlotte, NC 4 / 4 0.59 38% 41,700 / 32,600 74,300 

Byron Cameron/ 

Reston Pkwy Arlington, VA 4 / 4 0.51 44% 30,700 / 29,000 59,700 

US-70/Ebenezer 

Church Raleigh, NC 4 / 2 0.85 34% 52,200 / 6,100 58,300 

Sully Road/Old 

Ox Road Arlington, VA 6 / 4 0.82 19% 64,500 / 20,300 84,800 

US-74/Sharon 

Amity Charlotte, NC 6 / 4 0.61 20% 66,300 / 30,900 97,200 

US-64/Smithfield 

Road Knightdale, NC 6 / 2 0.76 20% 46,500 / 9,500 56,000 

US-1/New Hope 

Church Rd Raleigh, NC 8 / 4 0.76 19% 73,300 / 16,300 89,600 

Note: a Estimated based upon peak hour counts. 

CORSIM simulation models were constructed for all seven conventional and alternative 

intersections using consistent volume inputs for all alternatives using O-D features in the 

CORSIM model. The conventional intersections were modeled with existing geometry and the 

QR intersections were modeled to match the conventional intersection turn lanes. Other 

assumptions included: 

• Protected/permissive phasing was used for single-lane left turns and protected-only signal 

phasing was used for dual left turns, which is consistent with general signal timing practice. 

• Intersection splits and signal phasing were optimized based on intersection volumes. 

• Four cycle lengths were analyzed for each alternative: 90, 120, 150, and 180 seconds and 

the cycle length that produced the best (lowest) system time results were used. 

• The experiment considered 3 different volume levels, including the PM peak hour volumes, 

off-peak volumes, and volumes at 115 percent of the PM peak hour volumes. 

The experimental results were reported as total system travel time rather than intersection delays 

or similar measures. Alternative intersection designs can look very good at the main intersection 

while imposing large travel time penalties on left-turning vehicles at secondary intersections. 

Analyzing system-wide travel time inside a boundary constant between designs provide a more 

equitable comparison. CORSIM MOEs for QR intersections were compared to conventional 

intersections for each of the seven studied intersections, presented in table 18. Total system time 

and percent stop MOEs are reported for each of the three time periods and for an average of all 

three time periods. 
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Table 18. Summary of TRB study results.(27)

Measure 

Conv 

#1

QR 

#1

Conv 

#2

QR 

#2

Conv 

#3

QR 

#3

Conv 

#4

QR 

#4

Conv 

#5

QR 

#5

Conv 

#6

QR 

#6

Conv 

#7

QR 

#7

Off peak 

Total, v/h 67 64 50 48 37 34 73 74 112 89 36 31 36 31

PM peak 

Total, v/h 121 95 70 69 63 57 106 98 116 93 57 53 57 53

Peak+15% 

Total, v/h 170 135 91 83 103 73 146 125 179 124 66 57 66 57

Avg Total 

Time, v/h 120 98 70 66 68 55 108 99 136 102 53 47 53 47

Off-peak % 

Stops 0.73 1.10 0.74 0.98 0.59 0.60 0.71 0.94 0.46 0.90 0.68 0.60 0.68 0.60 

PM peak % 

Stops 0.80 1.06 0.80 106 0.50 0.59 0.70 0.81 0.72 0.85 0.67 0.65 0.67 0.65 

Peak+15% 

Stops 0.88 1.14 0.84 111 0.77 0.60 0.75 0.91 0.83 0.90 0.69 0.66 0.69 0.66 

Avg % 

Stops 0.81 1.10 0.79 105 0.62 0.60 0.72 0.89 0.67 0.89 0.68 0.64 0.68 0.64 

Average 

Cycle, sec 170 100 120 90 160 120 150 110 170 100 120 90 120 90

Average 

Veh-Miles 1936 2,088 1,620 1,704 1,464 1,573 2,419 2,550 2,484 2,664 1,460 1,525 1,460 1,525 

Veh Avg 

Served 2849 2,937 2,384 2,384 2,148 2,261 3,562 3,577 3,646 3,765 2,146 2,202 2,146 2,202 

Avg% 

Move Time 0.40 0.52 0.53 0.61 0.52 0.62 0.49 0.57 0.41 0.58 0.57 0.70 0.57 0.70 

Source: TRB 

The results show QR intersection had consistently lower system travel times for every PM and 

PM+15 percent volume scenario compared to a conventional intersection. In all but one case, the 

QR intersection had reduced system travel time, and in the one exception, system travel time was 

1-percent greater (intersection 3). Despite the increase in vehicle stops under the QR intersection

for all seven cases, there was a reduction in system travel time.

Results from FHWA AIIR Study

FHWA’s AIIR guide provided analyses that demonstrates how QR intersection design affects 

intersection throughput for several geometric conditions. Multiple simulation analyses were 

conducted for the AIIR guide comparing QR and conventional intersections under various 

volumes and geometric scenarios.(13)Results showed QR intersections operated comparably to 

conventional intersections in cases of moderate and balanced through volumes on both streets. 

However, QR intersections had higher throughput and lower travel times compared to the 

conventional intersections in cases of high through and moderate left-turn volumes on the major 

street and heavy through and left-turn volumes on the minor street. In the latter scenarios, the 

increase in throughput ranged from 5 to 20 percent, and travel time savings were between 50 and 

200 percent. Figure 74 compares throughput and average intersection delay of QR and 

conventional six-lane by four-lane intersection with multiple left-turn lanes under several 

different volume scenarios. 
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Simulation results showed that QR intersections performed comparably to conventional 

intersections for moderate and balanced through volumes on the major street. However, QR 

intersections had higher throughput and lower travel times compared to the conventional 

intersections for scenarios with heavy through and moderate left-turn volumes on the major 

street and heavy through and left-turn volumes on the minor street. For such scenarios, the 

increase in throughput ranged from 5 to 20 percent with 50 to 200 percent travel time savings. 

Source: FHWA 

Figure 74. Graphic. Throughput comparison of QR versus conventional intersection. 

Microsimulation analyses were conducted for four cases: 

A. Intersection of four-lane, two-way major street, two-lane, two-way minor street with one 

left-turn lane on the mainline, and a two-lane, two-way connector roadway. 

B. Intersection of four-lane major street, four-lane minor street with one left-turn lane on the 

mainline, and two-lane connector roadway. 

C. Intersection of six-lane major street, four-lane minor street with one left-turn lane on the 

mainline, and two-lane, two-way connector roadway. 

D. Intersection of six-lane major street, four-lane, two-way minor street with two left-turn 

lanes on the mainline, and four-lane, two-way connector roadway. 
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Simulation results showed: 

• For case A, the conventional intersection performed slightly better compared to the QR 

intersection. 

• For case B the conventional intersection was similar in operational performance compared 

to the QR intersection. 

• For case C, the QR intersection was similar in operational performance compared to the 

conventional intersection. 

• For case D, the QR intersection was significantly better than the conventional intersection 

in operational performance. 

Results from Huntersville Study

Before construction of the NC-73 project, very poor operations occurred near the US-21 and NC73 intersection during peak travel hours, frequently causing crashes and resulting in stopped 

traffic queuing across multiple adjacent intersections. Stopped queues on NC-73 would often 

extend from US-21 down the adjacent I-77 northbound ramp and onto I-77 during peak hours. If 

the QR intersection project was not constructed, 2030 peak hour delay could have worsened to 

predicted average delays of as much as 7-minutes per vehicle. Several operational safety studies 

were performed both prior to and post-construction: 

• A comparison of 2030 No Build and 2030 Build QR intersection operations showed that the 

QR intersection improvements would reduce peak hour network delay by 46 percent. 

• An operational capacity analysis was performed in 2014 by the North Carolina Department 

of Transportation (NCDOT) Congestion Management Section for the US-21 and NC-73

QR intersection and vicinity. At the time of the study in 2014, the intersection operated at 

overall LOS C with all movements operating acceptably at LOS D or better, and traffic 

queues did not extend down the I-77 northbound ramp onto I-77. 

• Travel time runs were performed in May 2014 as part of the routine signal timing for the 

NC-73 corridor. A review of the actual travel time runs showed that in the AM peak hour 

on eastbound NC-73 (from the I-77 southbound ramp to Holly Point Drive), vehicles 

averaged 90 seconds to travel approximately 2,350 ft between these points at an average 

travel speed of 24 mph; in the PM peak hour, the westbound to northbound movement had 

a travel time of 95 seconds and an average arterial speed of 17 mph. These results showed 

that the capacity analysis described in the previous bullet was reasonably calibrated to 

actual field conditions if not slightly more conservative. 

Capacity analysis was performed using 2014 AM/PM peak hour volumes to compare traffic 

operations with the QR intersection to how the intersection would have operated if the QR 

intersection would not have been constructed. Results showed that if the intersection reverted 

to a conventional all-movement intersection (with conventional turn lane improvements), the 

intersection would operate at overall LOS D, but near capacity with multiple movements 

operating at LOS F with some spillback and stopped queues on NC-73 would still extend from 

US-21 down the I-77 northbound ramp to I-77.

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CHAPTER 6 — OPERATIONAL ANALYSIS 

The previous chapter presented operational characteristics unique to QR intersections. To 

support decisions regarding the choice and design of a QR intersection, there needs to be an 

appropriate level of traffic operations analysis corresponding to the stage of the project 

development process. The level of analysis needs to be consistent with the available data, and 

that data needs to support the applied analysis tools. As vehicular traffic operations coincide with 

multimodal considerations, final intersection configurations and associated signal timing should 

be in balance with multimodal needs for each unique project context. 

A QR intersection configuration is a system of multiple intersections, including the main 

intersections and two secondary T-intersections at either end of the quadrant roadway. Therefore, 

operational analysis must consider the operations of each signalized intersection and the 

relationship among all signalized intersections. 

Necessary data to preform operational analysis may include the following elements: 

• Average daily traffic (ADT). 

• Speed (posted, design, or 85th percentile). 

• Weekday and weekend peak-hour intersection turning movement counts. 

• Weekday and weekend off-peak intersection turning movement counts. 

• Pedestrian volume at the intersection. 

• Bicycle volume at the intersection. 

• Proportion of the traffic movements composed of heavy vehicles. 

• Basic geometric data, including number of through and turn lanes and distances between 

the main and secondary T-intersections.

Measures of effectiveness are used to evaluate the operational efficiency of a particular design 

like the QR intersection. The FHWA Traffic Analysis Toolbox has identified the following seven 

basic measures of effectiveness for vehicle operations:(29) 

• Travel time: average time spent by vehicles traversing a facility, including control delay, in 

seconds or minutes per vehicle. 

• Speed: rate of motion (expressed in distance per unit of time).

• Delay: additional travel time experienced by travelers at speeds less than the free-flow 

(posted) speed (expressed in seconds or minutes). 

• Queues: length of queued vehicles waiting to be served by the system (expressed in 

distance or number of vehicles). 

• Stops: number of stops experienced by the section and/or corridor (based on a minimum 

travel speed threshold). 

• Density: number of vehicles on a street segment averaged over space (usually expressed in 

vehicles per mile or vehicles per mile per lane). 

• Travel time variance: a quantification of the unexpected non-recurring delay associated 

with excess travel demand (can be expressed in several ways). 
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The final two measures, density and travel time variance, are less applicable to an intersection 

treatment than an uninterrupted flow facility, but may still be considered during the operational 

analysis. While average speed and travel time apply to the QR intersection much like they would 

to a conventional intersection (as long as the analysis area includes the entire configuration), the 

delay and stops performance measures must be carefully aggregated over the multiple 

intersections. Individual performance measures such as queues, stops, and delay across multiple 

intersections of a typical vehicle progressed through all intersections provides more meaningful 

comparisons versus simply adding or averaging the performance measures from each 

intersection. 

OPERATIONAL ANALYSIS TOOL OVERVIEW 

According to FHWA’s Traffic Analysis Toolbox, several tools are available to analyze traffic 

operations at intersections, including the following: 

• Planning-level analysis, such as critical lane volume, CAP-X(30)and VJUST.(31)

• Highway Capacity Manual 6th Edition (HCM) analysis. 

• Microsimulation analysis.

One major factor distinguishing these three types of analysis is the amount of time required to 

evaluate each scenario. HCM analysis may take several times as long as planning analysis, and 

microsimulation is typically an order of magnitude greater effort than HCM analyses. Planninglevel tools are useful in the initial feasibility analysis and to conduct a high-level comparison of 

the approximate number of lanes for a QR intersection. An operational analysis using a 

deterministic method, such as the HCM, is useful to perform a more detailed peak-hour 

performance analysis and to estimate performance measures like delay, travel time, and queue 

lengths. The HCM analysis may provide insight on additional geometric design and signal timing 

details. Microsimulation is useful for alternative intersection forms like the QR containing 

multiple closely-spaced intersections for which an HCM procedure has not been explicitly 

developed. Table 19 provides a summary of available analysis techniques for QR intersections. 

Table 19. QR intersection analysis techniques. 

Planning Highway Capacity Manual(9) Microscopic simulation 

Available using critical 

lane analysis tool like 

CAP-X and VJUST 

Difficult to perform now for motor vehicles; 

can analyze crossing pedestrians and bicycles. 

QR intersection-specific HCM procedure 

Can be performed for 

motor vehicles, pedestrians, 

and bicycles with most 

simulation packages 

Figure 75 shows how to translate conventional turning movements into QR intersection 

movements. Most analysis software designed for QR intersections (such as CAP-X described 

later) will make the translation automatically. Most microsimulation packages start with an 

origin-destination matrix rather than intersection-level turning movement data, but analysts using 

software not designed for origin-destination formatting or making manual calculations will have 

to make the translations. Figure 75 depicts the quadrant roadway in the southwest quadrant, but 

the volume assignments can be derived in the same manner for any intersection quadrant. 
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© NCDOT 

Figure 75. Graphic. Translating turn movements from conventional to a QR intersection. 

For one approach, there are two potential paths for right turns—one using the quadrant roadway 

and one advancing to the main intersection and turning right. The former is the shortest and 

perhaps most attractive path for motorists to make a right turn; however, the later path is the 

most conventional to motorists. The volume assignments in figure 75 assumes that 100 percent 

of the right turns use the quadrant roadway; however, the model can be calibrated to local 

conditions and preferences by splitting the percentage of right turns onto the quadrant roadway 

or at the main intersection. An example of conventional intersection turning movement volumes 

converted to a QR intersection volumes in shown in figure 76.
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© NCDOT 

Figure 76. Graphic. Converting conventional to QR intersection volumes. 

PLANNING-LEVEL ANALYSIS 

Planning-level tools and methods are useful in the early stages of a project when a QR

intersection is being considered as an intersection improvement alternative. Planning-level tools 

and methods provide high-level analysis, typically providing no greater detail than volume-tocapacity (v/c) ratios and/or LOS computations. Travel time, delay, queue lengths, signal timings,

and specific geometric data are typically not inputs nor outputs of planning-level tools. In 

general, planning-level analysis results are useful for feasibility and high-level design features 

but are not directly tied to actual operational performance or operational model results. 

Critical Lane Capacity Analysis 

The critical lane volume (CLV) summation technique estimates intersection capacity by viewing 

the intersection as a finite space shared by a set of conflicting traffic movements. For example, 

an eastbound left turn cannot be made simultaneously with the westbound through movement. 

Therefore, the east-west CLV is the sum of the eastbound left turn and westbound through 

volumes divided by the lanes available for each movement (or the westbound left turn and 

eastbound through movement divided by the lanes available for each movement—whichever is 

greater). The north-south CLV total is calculated in the same manner. The sum of the CLVs for 

east-west and the north-south becomes the basis for calculating the v/c ratio for the intersection. 

The intersection v/c can be correlated to LOS based on the ranges shown in table 20. 
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Table 20. V/C correlation to LOS. 

V/C Ratio Corresponding LOS

< 0.73 C or Better

0.73 – 0.85 D

0.85 – 1.0 E

> 1.0 F

The assumed per-lane capacity of each QR intersection movement is a key parameter in the 

planning-level results. The capacity in an operational analysis is derived from the saturation flow 

rate and the green-to-cycle-length ratio. In a planning-level analysis, the combined capacity of 

two intersecting lanes is estimated through the critical lane volume at the crossing point. This 

value is reduced from a base, uninterrupted saturation flow rate of 1,800 to 1,900 vehicles-perhour-per-lane (vphpl) to account for lost time in the signal cycle. The typical critical lane volume 

used for all intersections in a tool like CAP-X is 1,600 vphpl. For the QR intersection, the 

saturation flow rate is higher due to the reduced lost time due to two-phase signal operations and 

the generally narrower intersection crossing distance compared to a conventional intersection. 

Table 21 provides the calculated values CLV capacities based on the number of signal phases. 

Table 21. CLV capacity by number of signal phases. 

Number of Signal Phases CLV Capacity

2 1750

3 1675

4 or more 1600

As an example, using the given intersection turning movement volumes converted to a QR

intersection volumes in figure 76, the procedure for calculating the CLV and corresponding LOS 

for both a conventional and QR intersection is provided in table 22. In the case of the QR 

intersection, the highest CLV among the three intersection governs overall LOS.
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Table 22. Conventional and QR intersection critical lane capacity analysis. 

Determinant Conventional 

Intersection 

Quadrant Rdwy 

Main Intersection 

Quadrant Rdwy 

Secondary-T (1) 

Quadrant Rdwy 

Secondary-T (2) 

CLV for E/W 

movements 

(highest 

directional CLV) 

1,050/2 + 240/1 = 765 

-or710/2 + 210/1 = 565 

1,300/2 = 650 

-or900/2 = 450 

1050/2 + 240/1 

= 765 

330/1 = 330 

-or210/1 = 210 

CLV for N/S 

movements 

(highest 

directional CLV) 

580/2 + 250/1 = 540 

-or1,100/2 + 310 = 810 

1,350/2 = 675 

-or790/2 = 245 

310/2 = 155 

 -or250/1 = 250

1,100/2 + 310/1 

= 810

Total (highest) 

intersection CLV 765+860 = 1,625 675+650 = 1,325 765+250 = 1,015 810+330 = 1,140 

V/C ratio 1,625/1,600 = 1.02 1325/1750 = 0.76 1,015/1,750 = 0.58 1,140/1,750 = 0.65 

Level of Service LOS F (over capacity) LOS D LOS C LOS C 

CAP-X Software 

For planning-level evaluation of QR intersections, the principal tool available is criticalmovement analysis, as implemented in CAP-X.(30) CAP-X is a tool used to evaluate select types 

of alternative intersections, including the QR intersection, requiring only peak volumes inputs. 

The tool, easily implemented in a spreadsheet workbook, is designed to work using simple inputs 

including:

• Turning movement counts at both the main and secondary T-intersections. 

• Heavy vehicle percentages. 

• Number of lanes on each intersection approach. 

• Estimate of future growth in traffic. 

The outputs are the approximate v/c ratios at the main intersection and each of the secondary Tintersections. Figure 77 is a screen capture from the downloadable spreadsheet. 

Note that when considering the result of the planning-level analysis, the worst intersection 

governs the operations of the entire QR intersection. In the CAP-X example shown in figure 77, 

the main intersection analysis results show an acceptable v/c of 0.51 and one of the secondary Tintersections has an acceptable v/c of 0.58; however, the other secondary T-intersection has an 

unacceptable v/c of 1.07 (slightly over capacity). In this case, the QR intersection would be 

considered unsatisfactory at a planning-level analysis. 

However, the CAP-X may rank the QR intersection at or close to the top of a list of alternative 

intersection choices. In this case, the CAP-X tool could be used to evaluate if additional through 

or turn lanes can be added at the deficient secondary T-intersection to attain satisfactory 

operations. To evaluate any QR intersection design variation, the analyst would need to develop 

their own spreadsheet analysis consistent with the CAP-X methodology for evaluating CLV at 

each intersection. Another option would be to perform more detailed capacity analysis using 

other mesoscopic or microsimulation tools. 
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Source: VJUST 

Figure 77. Graphic. CAP-X planning level tool screen capture for QR intersection.
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HIGHWAY CAPACITY ANALYSIS ANALYSIS 

Analytical methods and deterministic models to establish highway capacity, vehicular delay, and 

other performance measures are required for a more detailed analysis. The HCM, as well as 

Highway Capacity Software (HCS) and other types of software available from private vendors, 

can be used to perform this level of analysis.(9) These tools use deterministic methods derived 

through analytical equations. 

The operational analysis methods provide further insight into the operational effects of geometric 

design and signal timing elements of a QR intersection compared to planning-level analysis 

methods. Advantages of the operational-level analysis approach in the HCM include the ability 

to balance operational detail with reasonable data input needs and analysis resource 

requirements. The HCM method provides more detailed output in the form of delays, travel time, 

and queue estimates than the planning-level method, while allowing for more customization and 

consideration of geometric variability and signal timing details. At the same time, its methods are 

typically applied more quickly than a more resource-intensive simulation analysis. Another key 

advantage of the HCM over simulation analysis is that the deterministic analysis framework 

offers consistency in performance estimation across analysts and interchange options. The HCM 

is generally regarded as the benchmark for operational performance estimation, and its equations 

and LOS stratification form the basis of comparison with other tools. 

Disadvantages of the current HCM include a limited scope of applicable geometry and lack of 

focus on network and system effects, including the interaction of the main and secondary Tintersections. Other operational characteristics of QR intersections not adequately handled by 

existing HCM methodologies include: 

• The arrival and departure of vehicles between the main and secondary T-intersections 

(signal coordination). 

• The potential for queuing to spill back from the main intersection through the secondary Tintersections. 

• The added travel time associated with left-turn movements using the quadrant roadway. 

• Potential for queuing in the single left-turn lanes on both intersecting roadways.

• The impact of transit stops within the boundary of the QR intersection. 

• Estimation of pedestrian or bicycle level of service. 

Current HCM analysis models analyze each intersection independently. Weaving movements 

and lane imbalance in positioning for downstream movements are not factored into the results. It 

is also not possible to cumulatively analyze the travel time and delay associated with left-turning 

movements that are made through a series of intersections. Vehicles are not “tracked” through 

the series of intersections, and thus the net impact to left-turn delay and vehicle travel time is not 

readily comparable to conventional intersection operations. 

The RCUT Informational Guide provides a step-by-step procedure for calculating delay for 

indirect left-turn movements and integrating into the overall intersection delay calculations.(21)

This methodology has been adapted for determining the additional left turn delay at a QR 

intersection and the computational steps are provided below. 
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1. Given the turning movement demand estimate, redistribute the demands across the QR 

intersection as shown earlier in the chapter. For the remainder of this procedure, work 

with the redistributed demands. 

2. Calculate control delays for all approaches to all three signals using the “incremental 

queue analysis” delay estimation methodology from Chapter 19 of the HCM.(9) Mimic 

RTOR operations where applicable by analyzing approaches as if they had protectedpermissive signals, with the appropriate critical gap and follow-up times. 

3. Calculate queue lengths at each intersection storage bay and compare to actual storage bay 

lengths. If the 95-percent queue length exceeds the storage bay provided, and if spillback 

occurs, consider using microscopic simulation. 

4. Use table 23 to determine the additional left-turn travel times for each movement (based 

on intersection spacing) using the estimated free-flow speed multiplied by the distance 

traveled. 

5. Estimate the overall control delays for major street left turns, through movements, and 

right turns by adding the control delay from each of the three signals. 

6. Estimate the extra travel time for the minor street left turn and through vehicles by adding 

the control delays from step 2 from each signal those vehicles traverse and the travel times 

from step 4. 

7. Apply a LOS scale to the overall control delays and extra travel times from steps 5 

through 6 if desired. 

While the HCM has the limitations discussed above, it does provide the consistency agencies 

need for evaluating alternatives. The HCM is an international reference manual overseen by an 

independent committee of experts in the field, and thus is often the basis for policy decisions and 

LOS thresholds for intersection selection. 

Level of Service Definition 

The LOS of an entire QR intersection in the HCM can only be evaluated on an intersection-byintersection basis. At present, there is no methodology for establishing an overall LOS grade for 

the QR intersection; rather the intersection evaluation should be based on the “worst” operations 

of the multiple signalized intersections within the QR intersection footprint. Evaluation of the 

approach delay and LOS should be rated according to the thresholds established in table 23, 

which is reproduced from the HCM. 

Table 23. LOS criteria for signalized intersections.(9) 

LOS Control Delay (s/veh) 

A ≤10

B >10–20

C >20–35

D >35–55

E >55–80

F >80 
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Computational Steps 

The basic methodology for analyzing QR intersection operations is shown in flowchart form in

figure 78. The QR intersection methodology mirrors the HCM signalized intersection method 

(HCM 6

th Edition Exhibit 19-18), but with additional considerations, including: 

• Assigning conventional turning movements to the patterns permitted by the QR 

intersection’s geometry. 

• Assuming optimal progression arriving at the main intersection and queues do not exceed 

available storage length. 

Source: Adapted from 6th Edition HCM Exhibit 19-18

Figure 78. Graphic. HCM method for QR evaluation.
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A variety of input data are required to apply the HCM methodology to evaluate a QR 

intersection. These generally fall into the three categories of geometric, traffic and signalization 

conditions. Table 24 summarizes the input data needed for evaluating a QR intersection using the 

HCM methodology.

Table 24. Input data for HCM evaluation of QR. 

Type of Condition Parameter 

Traffic 

Characteristics 

Demand volume by O-D or turning movement 

Right-turn-on-red flow rate 

Percent heavy vehicles 

Intersection peak hour factor 

Platoon ratios 

Upstream filtering adjustment factor 

Initial queue 

Base saturation flow rate 

Lane utilization adjustment factor 

Approach speed 

Pedestrian flow rate 

Bicycle flow rate 

Local bus stopping rate 

Geometric Design 

Number of lanes 

Average lane width 

Turn bay lengths 

Approach grades 

Turning radii for all turning movements 

Distance between main and secondary T-intersections 

Existence of exclusive or shared left- or right-turn lanes 

Signal Control 

Type of signal control 

Phase sequence 

Cycle length 

Green times 

Yellow-plus-all-red change-and-clearance interval 

Offsets 

Maximum, minimum green, passage times, phase recall (for actuated control) 

Minimum pedestrian green 

Phase plan 

Other 

Analysis period 

85th percentile, design, or posted speed 

Area type 

Source: Adapted from 6th Edition HCM Exhibit 19-11
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One of the key considerations in evaluating QR intersections in an HCM context is traffic signal 

optimization. The HCM methodology does not include a methodology for optimizing QR 

intersection traffic signals. Therefore, other tools are needed for optimizing QR intersection 

signal timing plans prior to implementation in the HCM or a simulation environment. To 

overcome this challenge, analysts often use off-the-shelf signal optimization tools to arrive at 

signal timing parameters for analysis of unbuilt QR intersections. 

When optimization tools are not available, some simplified optimization techniques can be 

applied. Since all QR intersections operate with two-phase signals at the main intersection and 

three-phase signals at the secondary T-intersections, simple base signal timing assumptions can 

be developed by balancing the phasing split according to the proportional volumes on both 

intersecting roadways. Once the main intersection split is established, the secondary Tintersections can be developed to match the green time allocated for the opposite signal phase, 

and the offset is adjusted such that left-turn vehicles using the quadrant roadway are not unduly 

delayed by multiple stops. The base signal phasing assumption can be tested and modified using 

microsimulation analysis. 

MICROSIMULATION ANALYSIS 

Microsimulation analysis tools are capable of modeling the unique operational aspects of 

alternative intersections, including QR intersections. Capacity is derived from car-following 

models rather than static assumptions, and all intersections within a QR intersection 

configuration can be included in a single network. Among the more critical features required to 

accurately model QR intersections is the ability to replicate and track the turning movement 

patterns, including lane changing and lane assignment preferences. A list of calibration factors 

and validation parameters are described below. The selected tool must be able to include these. A 

discussion on the calibration process can be found on FHWA’s Traffic Analysis Tools website in 

Volumes III or IV.(33) 

Advantages of microsimulation models include flexible customization and configuration of 

geometry, signal timing, and other operational parameters. However, the greatest advantage is 

that microsimulation models can output “system” measures of effectiveness for QR intersections, 

so that overall movement delay, travel times, and number of stops can be readily compared to 

conventional or other unconventional intersection designs. Post-processing tools can be 

constructed that use microsimulation data output to generate movement-specific MOEs, 

including measurement of travel time and speeds for each QR left-turn movement. Models can 

also generate safety-surrogate data such as stops and near-misses. 

Disadvantages of microsimulation models include the time, budget, data required for input and 

proper calibration, and the knowledge of how to properly choose, set-up, run, validate, and 

obtain results. Another limitation of simulation is the need to calibrate and validate the effort, as 

well as the potential implications of failing to do so. The analyst needs to understand the many 

unique operational attributes of the QR intersection including saturation flow rate, speed profiles, 

lost time and gap acceptance, and know how to replicate those in simulation. There may also be 

variability in the results of QR intersection evaluations performed by different analysts. 

Calibration Factors 

Key data needed to establish calibration factors for QR intersection simulation models include: 

• Field-measured free-flow speeds through all QR intersections. For calibration, speeds on 

the QR intersection roadway are below the free-flow speeds of through movement 

approaches, as discussed in chapter 5. If the model does not accurately reflect observed 
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field conditions, an alternate approach is to observe free-flow speeds from existing or 

similar roadways with similar intersection controls and driver behavior.

• Accurately modeling signalized control of QR intersections requires exploring whether the 

main and secondary T-intersections should be modeled with one versus multiple 

controllers. The selected tool should employ signal control logic that is flexible enough to 

allow modeling of multiple or single controllers. Details of QR intersection signalization 

strategies are presented in chapters 5 and 8. 

Validation Factors 

Several validation parameters are recommended for accurately modeling existing QR 

intersections in simulation. Data should be collected in existing conditions to support these 

parameters and the testing of the base conditions model, including:

• O-D volumes collected beyond the area of influence of the QR intersection footprint. A 

calibrated base model should be able to reflect similar volumes and travel patterns 

compared to existing field conditions. For QR intersections, the O-D patterns are adjusted 

and compared to the conventional intersection to match QR intersection geometry and 

permitted movements. 

• Route travel times collected using GPS receivers, floating car, or other collection 

techniques. A calibrated model should be able to reflect similar travel times compared to 

existing field conditions. 

• Average and 95th percentile queue lengths, particularly for through and left-turn 

movements. A calibrated model should be able to reflect reasonably similar queue lengths 

compared to existing field conditions. 

SUMMARY 

There are a range of tools that can be used for planning and operational analysis of QR 

intersections. Table 25 provides guidance on the advantages and disadvantages of using each tool 

and when each tool is best used in the planning and design process. 

Table 25. Best use of analysis tools. 

Analysis Tool Advantages Disadvantages Use When Conducting....

CAP-X /other 

planning-level 

Simple inputs and 

results 

Many default assumptions; 

difficult to calibrate 

Most planning-level analysis 

HCM or other 

macroscopic 

Simple inputs and 

LOS outputs 

Does not consider 

interaction between signals 

Planning level analysis with 

deeper knowledge of default 

values 

Microscopic 

Models 

Detailed operational 

results and MOEs by 

movement 

More time consuming to 

code and post-process to 

obtain LOS results 

Operations level analysis or to test 

and implement signal timings 

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CHAPTER 7 — GEOMETRIC DESIGN

This chapter describes the typical QR intersection design approach and provides guidance for 

geometric features. This chapter presents best practice design criteria developed by experienced 

local and State agencies, and also provides information regarding implementations in several 

States. It requires input from the multimodal considerations (chapter 3), safety assessment 

(chapter 4), and traffic operational analysis (chapters 5 and 6). The guidance in this chapter is 

intended to supplement national resources on intersections that apply basic design principles.

DESIGN APPROACH 

Developing the geometric layout for an intersection configuration requires considering the 

relationship and interaction of safety, operations, and design. In addition, it requires 

understanding the trade-offs of the physical, environmental, or ROW constraints for the proposed 

QR intersection that may preclude ideal median width or crossover location. As with any 

intersection form under consideration, undesirable geometry cannot necessarily be mitigated by 

signing and pavement markings. The overarching goal is to provide geometry that serves various 

users and meets their expectations. This includes clear and defined geometrics that are 

supplemented with signing and pavement markings. Figure 79 highlights the characteristic 

features of a QR intersection with signals at the main and secondary T-intersections. 

 © NCDOT 

Figure 79. Graphic. QR intersection characteristics. 
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GEOMETRIC DESIGN PRINCIPLES 

The geometric design of a QR intersection introduces some unique design elements not typically 

present at a conventional intersection. These elements include: 

• The roadway in one intersection quadrant, either constructed new as part of the QR 

intersection or an existing street that is repurposed to function as the quadrant roadway. 

• Potential change in access to land uses in the four intersection quadrants compared to a 

conventional intersection, resulting in access strategies and management considerations to 

promote safe and efficient access to adjacent properties. 

• Closely spaced signals on both crossing roadways that require coordination.

• Restriction of left and U-turns at the main intersection, enforced by positive guidance using 

design elements and/or traffic control devices to reduce chances of driver error. 

• Signing, marking, and geometric design promoting safe and efficient movements that 

would otherwise be unexpected or unfamiliar to motorists. 

GEOMETRIC DESIGN PARAMETERS 

QR intersections can have a variety of design characteristics to accommodate specific location 

context and access demands. The number of lanes on the quadrant roadway and the land use and 

functionality within the intersection quadrant can impact access management and ROW along 

both crossing roadways. 

Speed of the Quadrant Roadway 

As previously described in chapter 4, the recommended spacing between the main and secondary 

T-intersections should be approximately 500 ft based on minimum breaking distances between 

intersections and queue storage demands. It is desirous to have a minimum 100-ft tangent 

distance coming out of the curve approaching the secondary T-intersections to transition out of 

any superelevation and allow vehicles to align at 90 degrees at the stop bar. 

Given the short link distance and potential queues on the quadrant roadway, the roadway should 

be designed as a low speed urban roadway with posted speed range of 25 mph or 30 mph. 

According to AASHTO criteria, the corresponding horizontal curve radius for a 25-mph lowspeed roadway (DS=30) with a superelevation rate of 4 percent is 250 ft, and for a similar 30-

mph roadway (DS=35), the radii increases to 371 ft.(12) Greater curve radii may be used 

(particularly if a current roadway is being repurposed), but a larger radii encourages higher 

speeds than desired on the quadrant roadway. This basic QR intersection criteria is presented in 

figure 80 and figure 81 for speeds of 30 and 35 mph, respectively. 

Superelevation 

Because of the desired low-speed operations of the quadrant roadway, a maximum superelevation of 4 percent is the greatest superelevation that should be considered. With this 

superelevation rate, drainage outlets would need to be placed in the desired center raised 

concrete island. However, with lower speed design, superelevation may not be critical, thus 

eliminating the need for drainage catch basins in the center island. 
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© NCDOT 

Figure 80. Graphic. QR intersection geometric design (DS=30mph). 

© NCDOT 

Figure 81. Graphic. QR intersection geometric design (DS=35mph). 
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Number of Lanes on the Quadrant Roadway 

The planning phase of a QR intersection should include an analysis of the number of through and 

turning lanes required on the quadrant roadway to provide safe and efficient operations. Strong 

consideration should be given to lane assignment and vehicle paths through the quadrant 

roadway to reduce weaving movements along the quadrant roadway. Figure 82 through figure 84

illustrate three potential QR lane geometries, with a description of each lane geometry scenario 

following the figures. 

 © NCDOT 

Figure 82. Graphic. Two-lane quadrant roadway. 

 © NCDOT 

Figure 83. Graphic. Four-lane quadrant roadway. 
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 © NCDOT 

Figure 84. Graphic. Six-lane quadrant roadway. 

Two-lane quadrant roadway (figure 82): If there are only single left-turn lanes onto the 

quadrant roadway, the quadrant roadway can adequately store queue demands, and there are no 

intermittent driveways on the quadrant roadway, a two-lane quadrant roadway may be 

appropriate. This configuration includes one continual through lane in each direction and a 

shared third lane to create back-to-back left-turn lanes at both ends of the quadrant roadway. A 

separate right-turn lane can be developed if dual left-turn lanes are warranted. The single rightturn lane is typically sufficient as right turns are given more green time. Right turns are permitted 

during both the quadrant roadway phase and as a right-turn overlap with the left turn entering the 

quadrant roadway. If access is allowed along the quadrant roadway, a continuous raised median 

should traverse the entire length of the quadrant roadway to manage access to RIRO or 

directional openings only. 

Four-lane quadrant roadway (figure 83): If additional queue storage is determined to be 

needed (or if an intermediate break in the median is necessary), the quadrant roadway can be 

expanded to four lanes, two continuous lanes in each direction plus a back-to-back left-turn lane 

and single right-turn lane. It is recommended to use lane guidance striping and/or lane guidance 

signing to align right- and left-turn lanes with the lanes on the quadrant roadway that ultimately 

turn right or left leaving the quadrant roadway. Also, one of the right turns (the left turn that 

circles the quadrant roadway in a clockwise direction) can be made free-flow onto the quadrant 

roadway; however, this would be an impact to pedestrians. 

Six-lane quadrant roadway (figure 84): If multiple right- or left-turn lanes are needed turning 

onto the quadrant roadway at either secondary T-intersection, or analysis shows the need for 

additional queue storage on the quadrant roadway, a six-lane quadrant roadway may be 

appropriate. In this case, lane assignments must be carefully considered to avoid forcing either 

right- or left-turning lanes entering the quadrant roadway to change lanes to reach their desired 

exit lanes. A six-lane configuration was used at the SR-4/SR-4 Bypass QR intersection, but with 

single left turns from both intersecting roadways onto the quadrant roadway.
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Stopping Sight Distance

A low-speed quadrant roadway requires less stopping sight distance, such that typical curb and 

gutter and sidewalk widths may provide adequate clear zone sight distance along the roadway. If 

there are RIRO or directional access points along the quadrant roadway, clear sight-distance 

triangles should be provided and maintained at the access point.

Lane Widths

There are no special lane width requirements for any of the roadway elements in a QR 

intersection, so lane widths of 11 or 12 ft are generally sufficient. If there are single-lane 

segments on the quadrant roadway, wider lane widths should be considered and/or shoulder 

width provided as room for vehicles to pass a stalled vehicle in the single lane. Lane widths may 

need to be adjusted if Tractor-Trailer/ Semi-Truck (TTST) vehicle traffic is considered 

significant. Also, intersection geometry and median and curbs should be designed to 

accommodate the selected design vehicle passing through the intersection. 

Design Access Controls

Every effort should be made to preserve T-intersection operations at both ends of the quadrant 

roadway. The best case would utilize physical features to control access, such as a lake, steep 

grade, or permanent structures in the natural path of a fourth leg to limit a future roadway. If 

physical restrictions are not possible, granting a limit of access line across the top end of the Tintersection would allow State or governing jurisdictions to deny a future roadway. If neither is 

possible and/or if local development and/or access pressures would otherwise stop a QR 

intersection project, a compromise of a fourth leg with restrictive covenants could be considered.

If the quadrant roadway is constructed as a new roadway and connectivity can be provided from 

either intersecting roadway to land parcels in the intersection quadrant containing the quadrant 

roadway, prohibiting access to the quadrant roadway can be ensured by establishing a control of 

access on the outside and the inside of the quadrant roadway for its entire length between the 

secondary T-intersections. 

Area Inscribed by the Quadrant Roadway

Using 500-ft secondary T-intersection spacing and 250-ft curve radius design parameters 

previously described in this chapter, the area inscribed by the quadrant roadway is approximately 

5 acres. Ideally, this land is preserved as part of the intersection through purchase and access to 

the quadrant roadway is limited. One corresponding use may be as a bioretention pond, as 

included at the Front Royal QR intersection as shown in figure 85.

The preservation of land and control of access may not always be possible in urban or suburban 

areas where corner parcels at busy intersections are prime real estate, or in the case when the QR 

intersection repurposes an existing roadway. In this case, every effort should be made to control 

access to the quadrant roadway to RIRO by installation of a raised median the length of the 

quadrant roadway. If intermediate access to land uses adjacent to or inscribed by the quadrant 

roadway is required, left turns should be permitted only from the quadrant roadway using 

directional left-turn channelization in the median, avoiding full median breaks.
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© NCDOT 

Figure 85. Photo. Use of parcel inside quadrant roadway for biorention pond.

OPERATIONAL EFFECTS OF GEOMETRIC DESIGN 

This section addresses the operational effects of geometric design on safety performance, traffic 

operations, and quality of service for pedestrians and bicyclists. There are several geometric 

design features potentially affecting how the QR intersection will operate once implemented. 

Preservation of Secondary T-Intersections 

Allowing a fourth leg at one or both of the secondary T-intersections can negatively impact 

secondary T-intersection operations, overall QR intersection effectiveness and ultimately driver 

perception of a QR intersection. The main intersection (two critical phases) can be coordinated 

with the secondary T-intersections (three critical phases) to operate with an overall efficiency of 

a two-phase signal. The addition of a fourth leg to either of the secondary T-intersections can 

introduce additional critical signal phases that compromise signal timing and coordination with 

the main intersection and elevate the secondary T-intersection to control overall QR intersection 

operations. However, commercial, retail, or residential developers (current or future) will view 

the signalized T-intersections as ideal locations to gain access to either intersecting roadway. 
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Figure 86 and figure 87 illustrate the secondary T-intersections that are preferred and to be 

avoided, respectively. 

 © NCDOT 

Figure 86. Graphic. Preferred secondary T-intersection geometry. 

 © NCDOT 

Figure 87. Graphic. Secondary T-intersection geometry to avoid. 

Recognizing that access needs may be political in nature, several compromise design scenarios 

have been developed that minimize the operational impacts of providing a fourth intersection leg. 

Note that in all of these compromises, the secondary T-intersection maintains three critical signal 

phases coordinated with the two-phase main intersection. However, each compromise may create 

additional pedestrian and/or bicycle conflicts and increase the potential for driver confusion. 

These compromise scenarios are illustrated and described in figure 88 through figure 91.
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Compromise 1: Allow through movements from the quadrant roadway across to the fourth leg 

while allowing only right turns from the fourth leg. The through movement can be served in the 

same signal phase with the quadrant roadway left turns in a shared through / left lane (or an 

exclusive through lane as volumes demand). The fourth-leg right-only movement may be yield 

controlled or free-flow into a right-turn or merge lane. 

 © NCDOT 

Figure 88. Graphic. Secondary T-intersection compromise 1. 

• Compromise 2: Allow right- and left-turn lanes exiting the fourth leg (but no through 

movement). The fourth-leg left turn can occur during the signal phase serving left turns 

exiting the quadrant roadway. The fourth-leg right-only movement may be yield controlled 

or free-flow into a right turn or merge lane. A caution with this compromise is that the 

prohibition of through movements (from both the quadrant roadway and from the fourth 

leg) may not be intuitive to motorists and may be difficult to control geometrically. 

 © NCDOT 

Figure 89. Graphic. Secondary T-intersection compromise 2. 
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• Compromise 3: Similar to compromise 2 but allow left turns to and from the fourth leg and 

prohibit through movements from the both the quadrant roadway and fourth leg. Note that 

the intersection still has three critical phases, and the added movements may degrade 

capacity and/or vehicle progression and may encourage undesirable paths to avoid using the 

QR intersection as intended. 

 © NCDOT 

Figure 90. Graphic. Secondary T-intersection compromise 3. 

• Compromise 4: Construct a four-leg, full-access intersection, but operate the intersection 

with seven signal phases including three critical phases.(34) Volumes on the outbound left 

turns from the fourth leg must be low to be served in the same phase as the quadrant 

outbound left. If the fourth-leg left turn or quadrant roadway through volumes are 

significant, intersection operations may degrade and thus impact the overall effectiveness of 

the QR intersection. 

 © NCDOT 

Figure 91. Graphic. Secondary T-intersection compromise 4. 
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Lesson Learned: Huntersville QR Intersection 

The Huntersville, North Carolina QR intersection is an example of a QR intersection where 

fourth legs were included at the secondary T-intersections. As illustrated below, the downstream 

secondary T-intersection on NC-73 permits direct left turns into a pre-existing shopping center 

driveway, a political mandate in order for the project to move forward. Despite proper markings 

and overhead signing directing motorists to use the quadrant loop, many motorists thought they 

would save time by turning left at the secondary T-intersection, traversing the shopping center 

internal loop roadway and finally making a right turn at the end of the loop road to complete the 

left onto northbound US-21 (path identified in the graphic below). While this is a shorter leftturn distance, travel time studies showed the intended QR left turn path provided the shortest 

left-turn travel time. Nonetheless, the internal loop road was unintentionally inundated with 

additional “through” trips. 

After the QR intersection project was complete, NCDOT and the Town of Huntersville wrestled 

with several options to remedy the situation, and ultimately a combination of traffic calming, 

education, and signal timing adjustments mitigated the adverse condition. Today, motorists 

generally find the designated quadrant roadway path to be preferable. Takeaways from this 

experience are: 1) avoid fourth legs at secondary T-intersection wherever possible; 2) where a 

fourth leg compromise is needed, expect that motorists will seek the perceived shortest path; and 

3) proactively use design, traffic calming, and access management strategies to ensure that 

motorists use the preferred left-turn path along the quadrant roadway as intended. 

© NCDOT; Background image © 2018 Google ® EarthTM

Figure 92. Graphic. Huntersville QR intersection access lessons learned. 
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Skewed Intersections

At conventional intersections, acute skewed left turns have a detrimental impact on intersection 

operations and safety. In some cases, skewed intersections afford the QR intersection to have 

operational and safety advantages compared to conventional intersections, as the hard-left turns 

are eliminated at the main intersection, which is particularly beneficial to larger vehicles.

At skewed intersections, left turns both to and from the quadrant roadway can (and should) be 

made at 90-degree angles to both intersecting roadways. If the quadrant roadway is located in the 

acute angle of the intersecting roadways, the quadrant roadway left-turn paths are shorter; 

however, significantly acute intersection angles could lead to insufficient storage on the quadrant 

roadway and/or longer spacing between the main and secondary T-intersections, which increases 

left-turn travel distances. Quadrant roadways located in the obtuse angle of a skewed intersection 

are typically undesirable, as the length of the quadrant roadway becomes significantly longer to 

achieve 90-degree angles with both intersecting roadways. This leads to longer left-turn travel 

distances and increased ROW and construction costs. Figure 93 and figure 94 illustrate the 

preferred acute and undesirable obtuse angles for quadrant roadways at skewed intersections. 

  NCDOT

Figure 93. Graphic. Preferred quadrants at skewed intersections. 

  NCDOT

Figure 94. Graphic. Undesirable quadrants at skewed intersections. 

Free-Flow Right-Turn Lanes

Similar to conventional intersections, the following elements need to be considered when 

designing free-flow right-turn lanes if implemented at QR intersections:

• The geometry at the pedestrian crossing in the 90-degree turn minimizes the speed 

difference with pedestrians at the crosswalk. 
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• Stopping sight distance for the approaching motorists and sight distances for the pedestrians 

approaching the potential oncoming automobiles should be clear of obstructions and 

provide sufficient visibility for various users.

• The location of the weaving/merging segment (where the free-flow right turn rejoins the 

through traffic exiting the intersection) in relation to the next decision point downstream of 

the intersection needs to be evaluated to minimize weaving beyond the intersection. It may 

be necessary to signalize the right turns as part of the crossover signal to eliminate a 

potential downstream weaving/merging segment.

• Driveways within the weaving/merging areas need to be avoided to minimize unexpected 

deceleration and unexpected maneuvers.

Figure 95 and figure 96 show two options for channelized right turns: 

 Source: FHWA 

Figure 95. Graphic. Types of channelized turns (1).(21)

 Source: FHWA

Figure 96. Graphic. Types of channelized turns (2).(21) 
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DESIGN GUIDANCE

The next few sections discuss key geometric design guidance for QR intersections:

• Pedestrian crossings.

• Main intersection left-turn prohibitions. 

• ROW requirements.

• Medians. 

• Design vehicle.

Pedestrian Crossings

The narrower street typical section of a QR intersection reduces the number of lanes crossed by 

pedestrians compared to a conventional intersection with multiple left- and/or right-turn lanes. At 

the secondary T-intersections, crosswalks are typically only needed at two locations to cross the 

either intersecting roadway. The pedestrian crossing should be placed only on the far side of the 

intersection (furthest from the main intersection) where pedestrians are only in conflict with 

right-turning vehicles from the quadrant roadway approach. Recommended pedestrian crossing 

locations at the main and secondary T-intersections are presented in figure 97. 

 NCDOT

Figure 97. Graphic. Pedestrian crosswalk placements.

Main Intersection Turn Prohibitions

At the main intersection, there are no physical barriers to vehicles making prohibited left or Uturns. Therefore, geometric design and proper signing and marking are important to eliminating 

or minimizing violations. One design strategy to deter prohibited turns is to construct raised 

medians on all intersection approaches where left-turn lanes would otherwise be provided. The 

raised medians deny potential left- or U-turning vehicles any refuge for making prohibited 

movements. The raised medians also provide a visible location for the posting of signs 

prohibiting left- and U-turn movements right at the main intersection. The median widths, 

offsets, and curb types should be designed to governing State or local standards and should not 

introduce an additional safety hazard at the intersection. 
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ROW Requirements

Due to the typical lack of need for dual left-turn lanes on either intersecting roadway, the QR 

intersection requires less ROW compared to a conventional intersection with dual left-turn lanes. 

Frontage along both intersecting roadways can also have higher costs and face greater limitations 

in the vicinity of the main intersection, where land costs are typically at a premium. QR 

intersections can also reduce ROW further at the main intersection by narrowing the approach 

median width from the secondary T-intersection through the main intersection. Where an 

existing roadway cannot be repurposed to a quadrant roadway, additional ROW is needed to 

construct a new quadrant roadway, and even greater ROW is needed to preserve the interior 

quadrant. The net ROW required for the QR intersection is typically more than a conventional 

intersection. 

Medians

Raised medians along both roadways should be extended as close to the crossing street through 

lanes of travel as possible, with very small nose radii, to visually reinforce and make the left-turn 

movement geometrically difficult and non-intuitive. The crosswalk can be placed behind the 

nose of the median, and while two-stage pedestrian crossing is typically unnecessary and should 

not be encouraged, the median does reduce pedestrian exposure to vehicle travel lanes. This main 

intersection design guidance is illustrated in figure 98. 

 NCDOT

Figure 98. Graphic. Main intersection design guidance. 
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Lesson Learned: Fairfield QR Intersection

The SR-4 / SR-4 Bypass quadrant roadway design removes all traditional left-turn movements from the 

major intersection, which initially proved challenging for motorists to understand and comply with. When 

the new intersection first opened, the City of Fairfield documented a large number of illegal turns. These 

illegal turns reduced significantly after the first week the intersection was open and decreased 90 percent 

within 8 months. However, after the project opening, many on the design team felt that the use of a 

physical barrier—such as a concrete median or landscaped island—and placing turn prohibition signs in 

those medians, would have been more effective in communicating the left-turn restrictions than simple 

transverse striping to prior left-turn lanes. These medians would have also fully restricted left turns to the 

development between the main and the secondary T-intersections instead of relying on regulatory signs as 

illustrated in figure 99. 

 NCDOT

Figure 99. Graphic. Fairfield median lessons learned.

Design Vehicles 

All movements at a QR intersection can and should be designed to accommodate the design 

vehicles on the intersecting roads, which are typically trucks and large vehicles, up to WB-67 

vehicles. If the QR intersection is located along an OSOW vehicle route, the medians at the 

secondary T-intersections should be designed to accommodate the additional turning width 

requirements, and single-lane portions of the quadrant roadway would need to be sufficiently 

wide to accommodate OSOW vehicle turning movements, potentially using mountable and/or 

traversable curbs.
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CHAPTER 8 — SIGNAL, MARKING, SIGNS, AND LIGHTING 

CONSIDERATIONS

This chapter discusses signal, signing, marking, and lighting design criteria and best practices for 

constructing and operating QR intersections. The guidance in this chapter supplements the 

national resources on intersection design highlighted in previous chapters, including the MUTCD

and local agency design criteria and policies.

(10) 

DESIGN PRINCIPLES AND APPROACH

Traffic signal design, signing, pavement marking, and lighting design at a QR intersection can be 

different from a conventional intersection, particularly related to the left-turn prohibitions at the 

main intersection. The following treatments need to be emphasized at QR intersections:

• Provide signage and pavement markings to indicate the prohibition of left turns. 

• Provide signage and pavement markings to establish wayfinding for right- and left-turn

movements through all QR intersections. 

• Provide a means for direct or indirect bicycle left turns. 

• Provide appropriate lighting at conflict points (i.e., both main and secondary T-intersection 

crossings) to emphasize the presence of various users. 

SIGNALS

Chapter 5 provides operational characteristics for potential signal phasing, cycle length, timing, 

and progression. At QR intersections, the main intersection is always signalized and, in most 

cases, both secondary T-intersections are signalized as well. This chapter provides guidance for 

planning and design of QR intersection signals. 

Signal Equipment Locations

The placement of signal poles and signal heads for the main intersection of a QR intersection 

follow the same criteria as signals at conventional intersections except that no left-turn signals 

are provided at the main intersection. The location of signal poles and signal heads at the main

and secondary T-intersections follow the same MUTCD guidance or State signal design 

standards as with a conventional intersection. At new QR intersections, pedestrian 

accommodations should be considered at all three intersections and should include pedestrian 

signals and accessible pedestrian signals/pushbuttons for all marked pedestrian crossing at all 

three intersections.

MUTCD standards call for signal heads to be placed no less than 40 ft beyond the stop bar, and 

no more than 180 ft, unless a supplemental nearside signal is provided. Because QR intersections 

are generally narrower compared to conventional intersections, supplemental near side signal 

heads are not typically required. Also, mast arm lengths are typically reduced because they do 

not have to hang left-turn signals over outside left-turn lanes as typical at conventional 

intersections. Most States and/or municipalities have their own standards for number and 

locations of signal heads for standard three- and four-leg intersections, and there are no special 

signal head placement requirements for a QR intersection that would override those governing 

standards. Whether wood poles, metal strain poles, or mast arms are used, all poles at all 

intersections should be located comfortably behind the curb lines and/or sidewalks where they 

are shielded from travel lanes. Figure 100 illustrates an example of typical mast arm signal pole 

placements at QR main and secondary T-intersections. 
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 NCDOT

Figure 100. Graphic. Typical mast arm pole, signal head, and cabinet placement.

As there are three signal cabinets at QR intersections, it is important that they be placed in a 

location so as not to obstruct vehicle sight distances. At the main intersection, decisions for 

signal cabinet placement are the same faced at a conventional intersection. At the secondary Tintersections, the logical placement is at the top of the T, where they are both out of the way of 

any vehicle lines of sight and reinforce that a fourth intersection leg is not desirable at any point 

in the future. When determining optimal signal cabinet placement, consider that a signal 

technician should be able to see all signal heads when working in the cabinet. 

Controllers

QR intersections include three signalized intersections operating as a system. In many cases, the 

signal controller technology will allow each intersection to be operated with a single controller, 

although a multiple controller strategy can be implemented as well. Use of a single controller can 

be accomplished by programming the controller with more than the typical two-ring cycle, 

maximizing the flexibility in timing each intersection. Table 26 lists advantages and 

disadvantages of each control strategy. 

A third alternative is to include a cabinet and controller at each intersection but link intersections 

with one controller operating as a “master” and the others as “slaves”. Each controller could 

work on its own, even in coordination, but linking outputs to inputs (using various parameters 

and logic) would allow further refinement of control, mimicking closely what a single controller 

can do. These linkages could be accomplished with hardwire connections or through peer-to-peer 

links on an Ethernet network. This approach might offer a “best of both” result.
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Table 26. Considerations for one versus three controllers at a QR intersection.

Criteria

Single Controller 

Advantages

Single Controller 

Disadvantages

Multiple Controllers 

Advantages

Multiple Controllers 

Disadvantages

Cost

Fewer 

components to 

purchase and 

maintain

Greater need for 

wiring between 

intersections

- Additional hardware 

and installation cost

Power

No 

communication 

set-up between 

controllers

- 

Phases/timings 

simpler to program 

and maintain

- 

Communications

Improved flow 

during free-run 

signal operations

- 

If a controller fails, 

other intersections still 

function

Need for all 

controllers to 

communicate

Wiring Single power 

service point

Long wire runs; cuts, 

voltage drops likely

Only conductor/

detector wire runs to 

controller

- 

Installation - Techs can’t view all 

signals from 1 cabinet

Each cabinet visible to 

signal heads it 

controls

- 

Operations Fewer 

components to fail

More difficult signal 

design/cabinet set-up

Can better control 

offsets

Could have 

undesirable gap outs 

w/low volumes

Note: - signifies no information.

Signal Warrants 

At appropriate locations for a QR intersection, the main intersection should meet MUTCD 

warrants for signalization. Secondary T-intersection volumes are comprised of displaced left-turn 

volumes that may or may not meet the same MUTCD signal warrants. If signalization of the 

secondary T-intersection is judged necessary to provide safe and efficient flow for indirect leftturn movements, the secondary T-intersection should not be required to independently meet 

signal warrants. This view of the secondary T-intersections being integral to overall intersection 

operational efficiency is not dissimilar DLT or RCUT intersections that have not historically 

required independent signal warrants at left-turn crossover or downstream U-turn intersections, 

respectively. Further, signalization of the secondary T-intersections can be operated in a 

coordinated signal phasing pattern that better serves left-turn movements without negatively 

impacting operational efficiency of the main through roadways. 

Pedestrian Signals

Pedestrian signal placement at QR intersections is very similar to placements at conventional 

four-leg or T-intersections. The only difference is the lack of pedestrian crossing one of the 

approaches at the secondary T-intersection. All pedestrian signals should be pedestrian-actuated, 

with pushbuttons mounted on the signal poles or, if not convenient, on a separate pedestal.

Bicycle Signals

Bicyclists making direct left turns by using bicycle boxes or the crosswalks of a shared-use path 

can be controlled with bicycle signals displaying green, yellow, and red bicycle indications. 
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These signals could assist bicyclists who are unfamiliar with the intended bicycle travel pattern 

at a QR intersection.

Signal Coordination 

The three traffic signals in a QR intersection should be interconnected by fiber if possible. On 

major roadways in urban and suburban areas, it is possible that both QR intersection roadways 

would already have fiber interconnectivity and the new or modified signals at the secondary Tintersections can be interconnected. If one or both of the secondary signals need connectivity to 

the main intersection, fiber runs(s) may be required as part of the QR intersection project. One 

possibility to avoid new fiber runs is to connect signals using controllers with GPS clocks. 

High Left-Turn Demand

If one of the left-turn movements has a high-demand volume compared to the other left-turn 

movements at the intersection, consideration should be given to setting the signal offsets and 

cycle length to better facilitate the high demand. The offsets and overall cycle lengths may be 

adjusted such that the left-turn demand entering the quadrant roadway follows the path of the 

quadrant roadway and arrives at the opposite end of the quadrant roadway right as the right- or 

left-turn phase turns green. This eliminates any start-up/lost time and queue storage needs for the 

left-turning vehicles. Determination of the cycle length and offsets based on travel speeds and 

intersection geometry would be best analyzed using microsimulation tools. 

Detection

Figure 101 illustrates potential detector placements at a QR intersection. Vehicle, bicycle, and 

pedestrian detection can be implemented similar to a conventional intersection to “call-off” 

phases having extra green time and giving the excess time to other phases for additional green 

time. This technique is relatively simple in a QR intersection since there are only two phases (at 

the main intersection) or three phases (at the secondary T-intersection) that need to be adjusted 

compared to a multi-phase signal at a conventional intersection. This technique can be 

particularly effective in off-peak times by providing more efficient green time to the rerouted left 

turns, mitigating the longer travel path. 
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  NCDOT

Figure 101. Graphic. Detector placements.

Permissive Left-Turn Phasing

To reduce queue storage requirements on A and D Streets upstream of the secondary Tintersections, signal operators may consider protective/permitted signal phasing for leading left 

turns and permitted/protected signal phasing for lagging left turns. The protected left-turn 

movement should overlap with right turns from the quadrant roadway. Analysis of intersection 

sight distance and crossing through/left-turn demands should be conducted to ensure there is no 

degradation in intersection safety anticipated by allowing permissive left-turn movements. 
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SIGNING

Signing for QR intersections follows the same industry practice and MUTCD guidelines for 

vehicles, pedestrians, and bicyclists as for conventional intersections. In addition, QR 

intersection signing needs to provide motorists wayfinding at appropriate locations along all 

turning-movement paths through the QR intersection. Since QR intersections tend to be placed in 

urban areas, consideration for sign placement should be developed early in the life of the project 

to assist with ROW and utility constraints.

At a QR intersection, drivers may not expect the direct left- and U-turn prohibitions at the main 

intersection. Therefore, regulatory signing must be used to communicate these movements are 

prohibited. QR intersections require an alternate path for left turns that differ for each 

intersection approach. Therefore, signing in advance of the main intersection to guide leftturning vehicle paths is recommended. As indicated driver expectation is to be allowed to 

execute a left turn, advance signing should be required rather than recommended.

Regulatory Signs

The MUTCD does not provide explicit QR intersection signing concepts. However, States with 

QR intersections have used MUTCD regulatory signs supplemented with their State standards. 

Regulatory signs should be located where these signs would normally be placed at conventional 

intersections. Proper application of regulatory highway signs including “no left turn” (R3-2) 

and/or “no left turn/U-turn” (R3-18) aid in the guidance of movements through the QR 

intersection and identify prohibited movements as illegal. Figure 102 through figure 104

illustrate the use of these typical regulatory signs. 

In addition to regulatory signs, ground mounted, and/or overhead guide signs are recommended 

to be placed at or near the intersection on one or both intersecting roadways to inform motorists 

of the required path for making left turns. Advance guide signs may be placed to inform 

motorists to:

• Move to the right or left lanes on A or D Streets. 

• Make a right or left turn at the main intersection. 

• Make a right or left turn at the secondary T-intersection. 

Typically, a minimum of two guide signs on each approach are needed: an advance guide sign, 

and a second sign located at the main or secondary T-intersection confirming the message on the 

advance guide sign. While QR intersection signs and placements may be experimental from an 

agency perspective, the intent is to have them conform to the MUTCD with regard to color, letter 

size based on functional street type, amount of legend, type of destinations, and design of 

directional arrows. Guide signing should include route markings (cardinal direction, route 

number, and arrow guidance) where either intersecting roadway is a numbered route, or by 

making specific guide signs for streets that are not on numbered routes. 

It is important not to “over-sign” a QR intersection. Sign clutter can have a detrimental effect on 

conveying messages and overall intersection safety performance. There is no need to identify the 

QR a special or unique intersection, nor need for special signs with unique messages or colors. 

Drivers should be guided using traditional guide signing wording and lettering common at 

conventional intersections and interchanges. Figure 105 illustrates part of a typical signing plan 

for a QR intersection at the juncture of two U.S. routes. Figure 106 illustrates a typical signing 

plan for a QR intersection at the juncture of a state route with local (municipal) street.
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 NCDOT

Figure 102. Photo. QR intersection regulatory signing, Fairfield, Ohio. 

 NCDOT

Figure 103. Photo. QR intersection regulatory signing, Front Royal, Virginia.

© NCDOT

Figure 104. Photo. QR intersection regulatory signing, Huntersville, North Carolina.
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 NCDOT

Figure 105. Graphic. Typical QR intersection signing plan for juncture of two U.S. routes. 
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 NCDOT

Figure 106. Graphic. Typical QR intersection signing plan for juncture of State/local route.
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Overhead and Special Signing

Motorists must be specially informed when they need to first turn right to make a left-turn 

movement. This is particularly important for motorists who may have to move from the left lane 

of the street to the right lane on multi-lane facilities. For these movements, the use of overhead 

signs is highly recommended. Sign placement is based on providing the motorist adequate time 

and distance to react to their message. 

Figure 107 and figure 108 provides an example of the overhead guide sign placement and 

messages at the NC-73 / US-21 intersection. This location included additional overhead signing 

at the interstate off-ramp intersection upstream of the QR main intersection. Figure 109 through 

figure 111 include field photos of overhead signs placed at several different QR intersection 

locations. 

 Town of Huntersville, NC

Figure 107. Graphic. QR intersection overhead signing plan for westbound NC-73. 

 Town of Huntersville, NC

Figure 108. Graphic. QR intersection overhead signing plan for eastbound NC-73.
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 NCDOT

Figure 109. Photo. Examples of QR overhead signing, Hunstersville, North Carolina. 

 NCDOT

Figure 110. Photo. Examples of QR overhead signing, Front Royal, Virginia.

 NCDOT

Figure 111. Photo. Examples of QR overhead signing, Fairfield, Ohio. 
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Wayfinding Signing on Quadrant Roadway 

Many motorists may be initially unfamiliar with QR intersection operations, particularly left-turn

vehicles that must leave either roadway and travel on the quadrant roadway. Wayfinding signs 

are important to reinforce route patterns and pull motorists through the quadrant roadway. There 

may also be the case where hospital, evacuation routes, or other routes of significance turn left at 

the QR intersection and thus should be incorporated into the QR intersection signing plan. In 

cases where the QR is located close to an interstate that include services signs, additional 

guidance signs may be used to guide motorists through the QR intersection to services identified 

on the interstate, as is the case at the Huntersville QR intersection. Figure 112 illustrates 

wayfinding signs on the quadrant roadway at the Front Royal intersection, and figure 113

illustrates services guide signs on the Huntersville intersection, where one of the QR intersection 

movements serves traffic exiting I-77 immediately west of the QR intersection. 

 NCDOT

Figure 112. Photo. Route wayfinding signs on Front Royal quadrant roadway. 

 NCDOT

Figure 113. Photo. Services wayfinding signs on Huntersville quadrant roadway. 
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Pedestrian / Bicycle Signing

Recommended QR intersection signing and supplemental pavement markings for pedestrian and 

bicycle accommodations should follow MUTCD standards and/or local signing standards. There 

are no special requirements for pedestrian crossings at QR intersections and no QR intersections 

constructed to date uses bicycle queue boxes. Figure 114 illustrates the MUTCD standard bike 

box sign (D11-20a) that could be utilized at future QR intersections. 

Source: FHWA

Figure 114. Graphic. MUTCD signing for left-turn bike boxes.(10)

Figure 115 shows bike box illustrative signing developed for a local bike lane project in Seattle, 

Washington.(34) It must be noted that it does not conform to the current MUTCD. 

 City of Seattle, WA

Figure 115. Photo. Local example of bike box signing.
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PAVEMENT MARKING

The MUTCD does not provide guidance for pavement markings specifically for QR 

intersections. Pavement markings for the main intersection of a QR intersection generally follow 

the same principles for those at conventional intersections (with or without medians), including 

edge lines, lane lines, pavement arrows, and crosswalks for pedestrian and bicycle 

accommodations. 

In addition to traditional pavement markings, in-pavement lane guidance shields are used at each 

of the QR intersections constructed to date. Figure 116 and figure 117 illustrate lane marking 

shields to aid vehicle lane alignment and route guidance through QR intersections. 

 NCDOT

Figure 116. Photo. Directional shield pavement marking, Huntersville, North Carolina. 

 NCDOT

Figure 117. Photo. Directional shield pavement marking, Front Royal, Ohio. 
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CHAPTER 9 — CONSTRUCTION AND MAINTENANCE

QR intersection construction typically follows a sequence that might be similar as conventional 

intersections, with the overall goal to maintain non-motorized and motorized traffic during 

construction while providing a safe work environment. The context of the project location will 

inform the staging and sequencing of construction. 

QR intersection construction costs may be higher compared to conventional intersections given 

the number and extent of intersection improvements and the need for increased traffic control 

devices. This is true for both new quadrant roadway construction and for retrofit situations where 

an existing roadway is repurposed to perform the quadrant roadway function. 

The guidance in this chapter supplements the national resources on construction and 

maintenance, including the MUTCD and local agency design standards and policies. There is 

limited history in building QR intersections, but several different types and methods have been 

used to give examples of lessons learned during construction and/or maintenance. In the case that 

a new quadrant roadway is constructed, maintenance of traffic may be advantaged as the new 

roadway can be used to divert traffic around the main intersection, and present fewer constraints 

for lane additions, temporary construction activities at the main intersection, and provides a 

much larger staging area than at conventional intersection improvement projects.

CONSTRUCTION

North Carolina, Ohio, and Virginia have constructed QR intersections in recent years. These 

State transportation agencies could serve as resources for construction and maintenance 

guidance. As with any new type of street construction, additional communication, and 

coordination with construction contractors may streamline project implementation. 

Understanding lessons learned from agencies having developed QR intersections may reduce 

construction delays. 

One of the benefits of constructing QR intersections, versus other alternative intersections, is 

their ability to be constructed relatively easily when being converted from a conventional 

intersection. This is especially true when the quadrant roadway is new construction. Conversion 

includes removing existing left-turn lanes from the conventional intersection and installing raised 

medians at the main intersection, and construction of two new secondary T-intersections. Unlike 

other alternative intersections and interchanges that transpose traffic streams (such as DDIs and 

DLT intersections), there is no coordination needed in moving traffic movements from the right 

side of the street to the left side of the street. 

Intersection and/or Corridor Widening

Developing new QR intersections, much like conventional intersections, may require additional 

lanes to be added at the following locations: 

• At the secondary T-intersections. 

• Along an existing roadway being repurposed to function as a quadrant roadway. 

• On the far right for right-turn lanes. 
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Unlike a conventional intersection, which is primarily centered at the intersection of the two 

crossroads, QR intersections extend approximately one-eighth of a mile in two directions from 

the main intersection and include a new or repurposed quadrant roadway. Depending on the 

width of the existing ROW and where additional lanes are required, it may be more favorable to: 

• Widen symmetrically on both sides of the street. 

• Perform all widening exclusively on one side. 

• Use the quadrant roadway to maintain traffic. 

Each widening approach might be considered depending on project specific features. Decisions 

on each widening approach will primarily depend on the geometric design, project cost, 

maintenance of traffic plan, and overall impact to adjacent land owners and the community, 

particularly when ROW must be purchased. 

Construction Staging

The sequencing of construction phases for a QR intersection depends on the number of lanes, the 

width and ROW of crossing roadways, and the extent of construction needed for the quadrant 

roadway. While there are numerous variations to consider, two primary variations are provided 

below: 

1. Sequential construction: 

• Construct quadrant roadway (if new) or reconstruct existing roadway to serve as the 

quadrant roadway. 

• Improve geometries at secondary T-intersections and install permanent signals. 

• Improve both intersecting roadways, using quadrant roadway (when necessary) to detour 

traffic when making critical improvements on either roadway. 

• Open all QR intersections to traffic when all movements are open (no partial openings). 

2. Simultaneous construction: 

• Construct improvements along both intersecting roadways including all medians, pavement, 

drainage, bike lanes, sidewalk, and/or other multimodal features.

• At the same time, construct quadrant roadway (if new) or reconstruct existing roadway to 

serve as quadrant. 

• Detour left-turning traffic onto the quadrant roadway (permanently) and close left turns at 

the main intersection. 

• Finalize improvements at the main intersection and open all QR intersections. 

In using either of these construction staging plans, it is not recommended to open the QR 

intersection in phases; that is to open any of the indirect left-turn movements to traffic before 

other left-turn movements. Drivers must acclimate to the new left-turn patterns of the QR 

intersection and doing so more than once may confuse and frustrate motorists despite the best 

intended temporary traffic control measures.

(34) This was one of the lessons learned at the 

Fairfield, OH implementation as detailed in Intersection Profile 1 in Appendix A. 
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COSTS

The cost of converting a conventional intersection to a QR intersection varies depending on the 

specific project context. The general considerations and elements affecting costs of a QR 

intersection are similar to those at a conventional form. It may include the following 

considerations:

• Amount of additional ROW required for the new or repurposed quadrant roadway. 

• Number and length of additional roadway lanes required. 

• Area of new pavement and sidewalks.

• New and/or upgraded signalization and modifications to existing signal system. 

• Utility impacts including relocations, increased lighting, and/or new signal interconnect.

• Number of overhead signs and sign structures. 

• Access modifications. 

Total project costs associated with developing a new QR intersection may vary greatly 

depending on project and community specifics, including ROW acquisition costs, displacements, 

public outreach, and contractor biding. Typically, the most variant cost factor is ROW, which 

may or may not be a project requirement and can vary greatly by geographical location and 

density of adjacent land uses.

While the cost to implement a QR intersection is likely greater than the cost to construct a 

conventional intersection at the same project site, QR intersections are considerably less 

expensive than grade-separation alternatives and are likely compatible to other alternative 

intersection forms. Historically, QR intersection construction costs have been difficult to isolate, 

as projects to date have been part of a larger corridor projects and a significant bridge project.

Table 27 presents cost estimates developed from the four most recent QR intersection 

installations including the total project cost (if the QR was built within a larger construction 

project) and the actual (or best estimated) cost of the QR intersection.
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Table 27. Summary of costs associated with QR intersections. 

Location Project Description Open to 

Traffic 

Project / 

(QR) Costs

SR-4 at SR-4 

Bypass - Fairfield, 

Ohio

First, full QR to open in U.S.; part of larger project on 

SR-4 that included superstreet intersections; only QR 

intersection could equitably serve traffic on both roads

January 

2012

$28 M

($2.3 M)

US-21 at NC-73 - 

Huntersville, North 

Carolina 

QR Intersection part of a larger corridor project that 

included superstreet intersections; first QR that 

repurposed an existing street (Holly Point Drive)

March 

2012

$25 M

($1.8 M)

US-340/522 at SR55 - Front Royal, 

Virginia

QR built as part of major bridge replacement project 

spanning the Shenandoah River in western VA; was 

built to serve traffic “for the lifespan of the bridge”

December 

2017

$49.5 M

($2.5 M)

US-42 at KY-872 - 

Florence, Kentucky

This stand-alone quadrant roadway intersection 

improvement became the fourth pure QR intersection 

in the U.S. and the first in Kentucky

August 

2019 ($3.2 M) 

MAINTENANCE

Maintenance requirements at a QR intersection are similar to a conventional intersection. For 

maintenance of through lanes at the main intersection, lane closure will have reduced impacts as 

there is no adjacent left-turn lane, so there is less chance of vehicles traveling on both sides of 

the work zone simultaneously. Maintenance at the secondary T-intersections would be identical 

to that of any conventional T-intersection. 

There are additional traffic signals and equipment, ground-mounted and overhead signs, and 

pavement marking and potentially in-pavement guide markings to maintain throughout the life of 

the project. There are no additional challenges to performing routine or resurfacing maintenance, 

and typical processes follow the appropriate work zone guidelines as for all conventional 

intersections. However, there are also fewer signal heads and less lane detection to maintain at 

the main intersection. Like other conventional roadways, conducting maintenance activities 

during off-peak times can minimize traffic disruptions. 

In some cases, QR intersections provide the advantage of being able to locate utility vehicles 

within center medians to work on overhead signal, signs, and/or lighting fixtures, where utility 

vehicles at conventional intersections may have to block travel lanes or locate on private 

property to perform maintenance functions. 

Snow Removal 

Snow removal for a QR intersection is accomplished similar to a conventional intersection. 

Through lanes are plowed as part of the corridor, and snow is systematically pushed to the 

outside of the street. The quadrant roadway must be maintained to the same standard as the 

intersecting roadways for the intersection to function. Snow is pushed through the U-turn to the 

opposite side of the street.

Work Zone Traffic Control 

Part 6 of the MUTCD provides guidance regarding signing and marking needs during 

construction and temporary street and intersection configurations.(10) MUTCD principles and 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 9: CONSTRUCTION AND MAINTENANCE

141 

applications for conventional intersections and streets would apply to constructing a QR 

intersection. 

Depending on the construction phasing and sequences, the work zone traffic control includes the 

following types of regulatory information:

• Signalization, signing, and pavement markings to inform motorists traveling through the 

construction zone when they have the right-of-way and appropriate lane assignment. 

• Guidance information to inform unfamiliar motorists in making decisions whether to turn 

right, left, or continue through the intersection. 

• Guidance information to inform motorists of changes in the operation (e.g., lane changes) 

of the intersection due to construction activities. 

While there are numerous variations in constructing QR intersections, the regulatory, guidance, 

and construction-related functions must be provided throughout the construction phases and in 

accordance with MUTCD. 
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142 

Lesson Learned: Front Royal QR

A portion of SR-55 (West Strasburg Road) west of Route 340/522 (North Shenandoah Avenue) was closed 

for several weeks in October 2017, just prior to the final completion of the project. The temporary “detour” 

using the quadrant roadway (illustrated in the graphic to the right) allowed contractors to reconstruct the 

portion of SR-55 within the new QR intersection. The detour limited the need for temporary pavement 

construction and reduced the intersection construction schedule. Traffic was rerouted as follows:

• Drivers heading east on SR-55 from Strasburg turned right onto the quadrant roadway, which led to 

the new traffic signal at SR-55 / US-340/522. 

• Drivers then turned right on East Strasburg Road to reach Front Royal or left to reach I-66. 

• Drivers on SR-55 wanting to reach Strasburg passed through the main intersection, turned right onto 

the quadrant roadway at the new traffic signal and then turned left onto SR-55. 

Intentionally sequencing construction to close Route 55 between the quadrant roadway and Route 340/522 

for reconstruction went a long way to help acclimate motorists to using the quadrant roadway before the 

full opening. Prior to and during the construction “detour” implementation, the project public involvement 

teams conducted critical outreach efforts, which were vital to enhancing the public's understanding of the 

QR intersection’s function. Traffic delays due to the temporary six-week closure were disruptive to 

motorists, so everyone was extremely glad to see the construction end and all lanes accessible. 

  Virginia Department of Transportation.

Figure 118. Graphic. Front Royal construction maintenance of traffic lessons learned.

Provided by Virginia Department of Transportation. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | CHAPTER 9: CONSTRUCTION AND MAINTENANCE

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LAW ENFORCEMENT 

Initially, there may be additional law enforcement needs for a constructed QR intersection. Upon 

project opening, there is nothing to physically prohibit direct left turns at the main intersection. 

Enforcement during the period after the QR intersection is opened to traffic has been effective in 

helping drivers become familiar with intended operations and reducing illegal maneuvers. As the 

novelty effect of the new intersection operations subside, the need for extra enforcement will 

diminish. 

QUADRANT ROADWAY INFORMATIONAL GUIDE | APPENDIX A

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APPENDIX A – CATALOG OF KNOWN INSTALLATIONS IN THE U.S.

Appendix A includes information on all know full, partial, or hybrid QR intersections currently 

operational in the U.S. Table 28 presents project information and locations of all known full or 

partial QR intersections constructed in the U.S. Additional information is presented for several 

QR intersection designs, presented in intersection profiles in this Appendix. 

Table 28. Full, partial, and hybrid QR intersections in the U.S.

Intersection

City, State 

(Type) Description

Year 

Open

Location 

Coordinates

US-42 at KY872 (Hopeful 

Church)

Florence KY

(Full)

Fourth QR intersection in U.S.; Includes a new 3-

lane quadrant roadway with a mid-point access to 

parcels adjacent/inscribed by quadrant roadway

August 

2019

38°58'40.08"N 

84°39'26.49"W

Market St. at 

Kerr Avenue

Wilmington 

NC (2-quad)

Repurposed one roadway and built new roadway 

in opposite quadrant to create a dual-quadrant 

intersection; currently removes two of four lefts

August 

2018

34°14'52.55"N

77°51'49.57"W

US-340/522 

at SR-55

Front Royal 

VA (Full)

Part of $49M bridge project, QR built at terminal 

of new signature bridge over Shenandoah River; 

QR built to serve traffic “thru lifespan of bridge”

December 

2017

38°56'48.14" N 

78°11'58.20" W

NC-73 at US21 (Statesville 

Road)

Huntersville 

NC (Partial)

QR part of a larger superstreet project on NC-73; 

first QR that repurposed an existing street (Holly 

Point Drive) and serve inscribed development

March 

2012

35°26'32.42" N 

80°51'55.23" W

SR-4 (Ross 

Rd) at SR-4 

Bypass (Dixie 

Hwy)

Fairfield OH 

(Full)

First full QR in U.S.; part of a larger superstreet 

project on SR-4. SR-4 / SR-4 Bypass intersection 

had highest & balanced intersection volumes and 

superstreet would not work at this intersection

January 

2012

39°19'26.16" N 

84°30'16.50" W

SR-527 at 

SR-96

Mill Creek 

WA (Partial)

At this skewed intersection, one left-turn 

movement is removed from the main intersection, 

via 16th Avenue SE

2004 47°52'42.16" N 

122°12'25.16" W

US 97 (Bend 

Parkway) at 

Powers Road

Bend OR

(2-quad)

At this 2-quad intersection, both secondary Tintersections on minor street are unsignalized; 

major street is served by RIRO access points

2001 44°01'43.62" N 

121°18'56.01" W

US-220 at 

Church Street

Greensboro 

NC (Partial)

Left turns prohibited on 3 of 4 intersection 

approaches; SB left uses Cherry Street in SW 

quadrant; other two use City streets elsewhere

1977 36°05'15.75" N 

79°47'02.98" W

Telegraph Rd 

(US-24) at 

15-Mile Road

Bloomfield 

Hills MI 

(Hybrid)

Hybrid QR intersection combined with a Median 

U-turn crossover. Main intersection restricts all 

left turns, but only two left turn use QR (other 

two use median crossovers on Telegraph Road)

Mid 70’s 42°32'42.50" N 

83°17'00.16" W

Van Dyke at 

Chicago Road 

& 14 Mile Rd

Warren MI 

(Partial)

Partial QR intersections with unsignalized Tintersections along corridor; quadrant roadways 

in one quadrant “cut the corner” to remove direct 

left turns from Van Dyke Avenue

Mid 70’s

42°31'26.41" N 

83°01'43.65" W

42°32'12.95" N 

83°01'42.49" W

SR 55 at 

Empire Street

Bloomington 

IL (2-quad)

2-quad intersections in opposite quadrants; 

secondary T-intersections are signalized 1980’s 40°29'17.04" N 

88°57'07.62" W

Grand River 

Ave at MLK 

Lansing MI 

(Partial)

Partial QR; left turns prohibited only on Grand 

River and redirected to use Logan Access Road Mid 60’s 42°45'34.07" N 

84°33'59.23" W
QUADRANT ROADWAY INFORMATIONAL GUIDE | APPENDIX A

146 

 INTERSECTION PROFILE 1: SR-4 AT SR-4 BYPASS, FAIRFIELD, OH

 ODOT

Figure 119. Photo. SR-4 at SR-4 Bypass, Fairfield, Ohio. 

The City of Fairfield did not seek to be the first in the U.S. to implement a QR intersection, but 

as part of the SR-4 corridor improvement project, seen in figure 119, the QR intersection was 

found to be the best way to achieve acceptable levels of service and safety while considering the 

social, economic, and environmental costs of the improvement project. Although unique, it best 

met required criteria from project stakeholders including FHWA, the Ohio Department of 

Transportation (ODOT), the City of Fairfield, and the local community. The intersection 

improvement was not specifically developed as a QR intersection, as State and City engineers 

were not initially aware of the QR intersection concept, referring to the design as a “Diversion 

Road”. Once the QR intersection literature and materials were provided to the City, some of the 

public education materials were helpful closer to the project opening. 

The SR-4 / SR-4 Bypass QR intersection included a new roadway in the northwest intersection 

quadrant where the land was owned by ODOT. The intersection of SR-4 and SR-4 Bypass had 

a history of long delays and congestion-related crashes, five times the statewide average.

The QR intersection was projected to reduce crashes and enhance traffic flow to and from 

SR-4, which served 40,000 vehicles per day in 2010. There were initially 10 different 

conventional and alternative intersections studied as potential intersection improvements, and the 

QR intersection was shown to operate the best and have the least ROW and environmental 

impacts and was therefore selected as the preferred alternative and constructed. 

The design included a maximum number of lanes on the quadrant (six total) to provide two 

receiving lanes and dual left and dual right-turn lanes at each end of the quadrant roadway. The 

main and secondary T-intersections are spaced within in the ideal recommended range of 500 

and 550 ft. The design also included overhead signs on span wire and in-pavement markings on 

the quadrant roadways to assist with directional and lane assignments. Regulatory signing is used 

to prohibit left turns at the main intersection; however, there were no raised medians or other 

special signing or markings on either roadway approaching the QR intersection. 

There was an appropriate level of public involvement conducted throughout the planning 

process, including a project website, continual meetings with business owners, and local paper 
QUADRANT ROADWAY INFORMATIONAL GUIDE | APPENDIX A

147 

and TV media announcements, despite there being only a few businesses directly impacted by 

the QR intersection.

After Opening

In the weeks and months after opening, lessons learned were identified and published. In an 

article published in AWPA Reporter in 2013, authors Mann and Hoying made the following 

observations about pre- and post-conditions of the first QR intersection:

(34)

• During construction, portions of the newly constructed quadrant roadway were opened 

before all lanes on the receiving roads were complete, leading to motorist confusion and 

frustration. Temporary message boards were added as the project opened to help reinforce 

the new turning patterns. 

• In addition to problems created by the partial opening, driver habits and inattention created 

some challenges when the intersection opened, and many illegal left turns were being 

made. Through education and enforcement, the number of illegal left turns dropped by 90 

percent after the first month. 

• Left-turn restrictions should stand out through geometric design. Using a physical barrier, 

such as a concrete median or landscaped island, would have been more effective than 

adding transverse striping to previous left-turn lanes to communicate the left-turn 

restrictions. 

• The project met triple bottom-line goals of economic, social, and environmental impacts. 

Neither SR-4 or SR-4 Bypass had to be widened, eliminating roadside wetland impacts. 

The project also used existing local resources, including a large amount of fill obtained 

from sites around the city. Economically, the QR intersection greatly reduced delay and 

had little economic impact on existing business revenues. 

Crash data were collected and analyzed for the three years prior and the three years after the QR 

opened to evaluate safety performance of the QR intersection. Crashes at the main intersection

and the SR-4 / Diversion Road T-intersection were reduced in number and severity compared to 

the prior conventional intersection. However, there were a significant number of crashes, many 

resulting in injuries, at the SR-4 Bypass / Diversion Road intersection, bringing the threeintersection total to be greater than the “before” condition of a singular conventional intersection. 

Further evaluation of the crash data showed the clear majority of the SR-4 Bypass / Diversion 

Road crashes were rear-end crashes (72 percent), and further engineering studies are on-going to 

determine if signal timing, driver confusion or other cause are the root of the high crash rate at 

this one secondary T-intersection.

The overall success of the project was widely acknowledged, leading to receipt of the 2012 

Donald C. Schramm Transportation Improvement Award from the southwest Ohio Chapter of 

the American Society of Highway Engineers. 
QUADRANT ROADWAY INFORMATIONAL GUIDE | APPENDIX A

148 

INTERSECTION PROFILE 2: NC-73 AT US-21, HUNTERSVILLE, NC

 Town of Huntersville NC

Figure 120. Photo. NC-73 at US-21, Huntersville, North Carolina. 

The intersection of US-21 and NC-73 in Huntersville, North Carolina is the meeting of two

regionally significant corridors in the northern Charlotte region, as seen in figure 120. The 

intersection is in close proximity to I-77 and a high-level of service and retail development exists

in the interchange area. The intersection was controlled by a complex 8-phase signal, and 

experienced frequent crashes, long delays and queues that often backed-up onto the interstate 

ramps. 

In 2007, funding was appropriated to widen NC-73 and increase capacity at its intersection with 

US-21. During the planning process, a traditional widening concept was evaluated that would 

create dual left-turn lanes, dual through lanes and right-turn lanes on every intersection approach. 

However, a conventional intersection that maintained the 8-phase signal at the NC-73 / US-21 

intersection in close-proximity to the I-77 ramp terminals would always be subject to current 

weaving and queuing issues and result in congestion reaching the interstate ramp terminals. 

Alternative intersection improvement alternatives were also studied, including the QR 

intersection. Under the QR concept, the existing, underutilized Holly Point Drive, a publicmaintained city street, was found suitable to function as the quadrant roadway. At the time, there 

were no exact examples of a QR in the U.S. in a built-upon urban environment; however, it 

conceptually solved major issues relating to intersection proximity, reduction in signal phases, 

and maintained critical access to local businesses. Under the QR concept (that widens NC-73), 

the 2030 peak hour total network delays were forecast to be reduced by 46 percent compared to 

the conventional intersection improvements. 

Understanding the significant operational benefits that the QR would provide, State and local 

transportation officials and elected representatives recommended the QR intersection as the 

preferred improvement. Some area businesses owners and vocal members of the public 

expressed concerns about potential for negative impacts to businesses and the community. In 

response, Town and State officials made sure there was a robust public outreach and education 

process—both during and after project was complete. Multiple media releases and visualizations 
QUADRANT ROADWAY INFORMATIONAL GUIDE | APPENDIX A

149 

were presented to local newspapers, television stations, and websites to convey the purpose of 

the project and the benefits of the QR. The initial public outcry included e-mails and phone calls 

to public officials proclaiming the QR intersection to be “the worst idea in history” and claimed 

the project would “destroy local businesses”. Public officials and transportation engineers 

worked to address access public concerns and stood firm in their belief the QR intersection was 

the best choice. In 2009, the NC-73 project (inclusive of the QR intersection) began construction 

and was completed in March of 2012 as the second QR open in the U.S. 

The project deviated from a “pure” QR intersection in a couple of ways. First, the intersection 

operates as a partial QR intersection, as left turns are prohibited from NC-73 onto US-21 but are 

allowed from US-21 onto NC-73. Second, both secondary T-intersections include a fourth leg 

with full or partial access provisions. The fourth legs provide access to established regional 

businesses and there was no political will to relocate or remove these access points. To minimize 

the fourth-leg signal phasing impacts, the NC-73 / Holly Point intersection has directional 

crossovers to limit some movements, and the US-21 / Holly Point intersection is split-phased 

with no protected left-turn phases from US-21. 

After the project opened, public comments took a more positive tone. Citizens responded with 

comments like: “The restriction of left turns makes no sense, but the intersection sure works 100 

times better!” and, “Just wanted to express to the Town that after a couple of months of 

withholding judgment, I am convinced that the new traffic pattern has made a HUGE and 

positive difference in moving traffic through the intersection”. Most businesses embraced the 

project, as they did not experience a significant drop off in customers or revenues during 

construction or after the QR was in place. Motorists who once avoided the intersection due to 

routine congestion now find their way to the area for shopping and entertainment, understanding 

the extra travel distance for some movements translated into an overall timesaving. 

Several travel-time runs concluded the signal system was timed appropriately and was well

coordinated. Enforcement of the intersection turn prohibitions included citation of violating 

motorists (more initial but fewer over time) but many motorists were self-policing of drivers 

attempting to make the restricted left turn by blowing their horns to keep them moving. Even

though a vigorous public outreach and education campaign was conducted, at first drivers were

tentative and seemed to not trust the signage and pavement markings guiding them to turn in a 

direction different from what they had been accustomed to for many years. Area business owners 

were initially concerned about the new traffic pattern and change in access in-and-around the 

intersection. This was to be expected since patrons would not only have to navigate a new 

unconventional intersection, but also find new ways in and out of limited access driveways, some 

that had full access prior to the intersection improvement project.

In 2014, an analysis was performed by NCDOT to compare traffic operations with the QR

intersection in place to how the intersection would have operated if the conventional 

improvements had been made. In 2014, the QR intersection operated at overall LOS C with all

individual lane groups operating at LOS D or better and traffic queues did not extend to the 

interstate ramps. Calibrated analysis of the conventional intersection improvements showed 

operations would be near capacity, with multiple movements operating at LOS F and queues 

extending from US-21 onto the I-77 ramps. A crash analysis conducted in 2017 compared three 

years of crash data prior to construction to three years after the project opened. The data 

suggested that crashes adjusted by volume growth increased by nine percent, but the crash 

severity index increased by only one percent. 
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150 

INTERSECTION PROFILE 3: US-340/522 AT SR-55, FRONT ROYAL, VA

 Virginia Department of Transportation 

Figure 121. Photo. US-340/522 at SR-55, Front Royal, Virginia. Provided by Virginia 

Department of Transportation. 

Located on the northern outskirts of the Town of Front Royal, Virginia’s first QR intersection was 

constructed at the intersection of US-340/522 at SR-55 as part of a major bridge replacement project. 

The 2,000-ft South Fork Bridge, spanning the Shenandoah River and the Norfolk and Southern 

Railroad needed replacement, as it was a low sufficiency-rated truss arch bridge similar to the I-35 

Mississippi River Bridge that collapsed in Minneapolis in 2006. The intersection of US-340/522 at 

SR-55 is a few hundred feet from the end of the bridge abutment and VDOT wanted an intersection 

with a capacity that would maximize the life of the intersection and complement the longevity of the 

bridge design. 

A primary goal of this project was to significantly reduce congestion and improve safety on US340/522, a route that carries volumes equivalent to nearby I-66 (approximately 30,000 vpd). A 

regional Small Area Plan study showed that conventional improvements at the US-340/522 / SR-55 

intersection would break down in 20 years, and VDOT wanted an intersection that would 

complement the longevity of the bridge design. Significant development was planned in this area, 

including a proposed Walmart in the northwest intersection quadrant. Design context was also 

important, as this route is a gateway into Shenandoah National Park and there are many historic 

elements in the area. 

VDOT began to develop intersection alternatives with a dozen different concepts—including 

roundabouts, superstreets, and grade separation—that were tested using operational models. Gradeseparated alternatives were dismissed as being too costly and having too great an impact on historic 

elements. An early favorite was a DLT intersection that moved left turns to/from SR-55 “out of the 

way”, reducing conflicts with US-340/522 through traffic, even though left turns experienced lesser 

operational benefits. However, there were concerns that adequate storage for the upstream left-turn 

lanes could not be provided without encroaching on the bridge abutment. When variations of the 

DLT intersection were conceptualized to resolve queuing requirements and work in the computer 

model, the configuration began resembling a QR intersection. Once recognized, the QR intersection 

alternative was added to study and functioned exceedingly well. 

At the time the project began in 2008, this would have been the first QR intersection built in the U.S., 

and wanting to do full due diligence, VDOT referred to the FHWA QR Tech Brief and other 

publications for concept and design guidance and performed CAP-X and CORSIM analysis to 

validate traffic operations. Models showed the QR main intersection would function at LOS C and 

the secondary T-intersections at LOS A through the design year of 2040. 
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151 

The intersection context also favored the QR intersection. SR-55 to the east, accessing the locally 

referred to “Riverton area”, is land-locked by the river and floodplains and will never heavily 

develop. The major movements would always be through traffic on US-340/522 and turns to/from 

SR-55 to the north to access I-66. 

Prior to the QR concept development, a Walmart was proposed in the intersection quadrant the QR 

intersection was ultimately located in, but the development plan was rejected by the City. With no 

pending development plans, VDOT was able to purchase the entire quadrant. The purchase of the 

quadrant added approximately $1M to the project cost (compared to conventional intersection 

improvements), but the project team viewed that as a bargain compared to the cost of grade 

separation. Further, any intersection improvement project would require maintenance of storm water 

on-site (stormwater credits could not be purchased) and the interior of the quadrant became a perfect 

fit for a stormwater management basin. 

The protection of the secondary T-intersections was made easier by the fact that one of the secondary 

T-intersections was too close to the bridge abutment to construct a fourth leg. The other Tintersection on SR-55 was granted limited access by the Commonwealth. Limited access can be 

broken, but not without permission by the highest level of the State that would likely deny any such 

future request to maintain the integrity of the QR intersection. Subsequently, when a service 

station/convenience mart was proposed on the adjacent property, VDOT was able to tightly control 

access and protect the integrity of the QR intersection. 

Signing plan development included an overhead sign structure on the bridge that focused on 

communicating directions (what the motorist SHOULD to) rather than on turn prohibitions (telling 

motorists what they should NOT do). Providing a clear and explicit sign plan was a concern of the 

design team throughout the development of the project. Later in the project, additional diagrammatic 

signs and pavement shields were added as the plans were finalized to provide additional wayfinding. 

A public involvement plan was key to the success of the QR intersection, and the project public 

meetings required citizens entering the meeting to first watch a narrated and animated short video to 

explain the goals of the project, how the project alternatives were developed and shortlisted, and why 

the QR was the preferred alternative. The video included side-by-side comparison of QR and 

alternative intersection configurations and many project operations and safety MOEs. It also showed 

how some of the QR intersection turning movement patters were not dissimilar to loop ramp 

movements at the US-340/522 / I-66 interchange, which resonated well with the citizens. After the 

public meetings, the public reaction was estimated at 70/30 in favor of the project with just a few 

vocal critics of the project. The project team coordinated with GPS/mapping companies in advance to 

have the revised traffic patterns reflected on opening day so turn-by-turn navigation instructions 

accurately guided motorists through the new intersection. 

Once the project was opened, VDOT engineers were pleasantly surprised at how well people adapted 

to the QR intersection. There were the occasional violators and others who slowed or stopped at the 

intersection out of confusion, but that did not become a safety problem. One of the advantages at the 

project opening is that drivers were so used to varying traffic patterns employed during the work-inprogress construction phases—that included a final phase where everybody was forced to use the QR 

while a final section of US-340/522 was rebuilt—that the final product was no less intuitive to 

motorists and they just adapted without any significant level of enforcement. The result is that 

intersection queues are cleared every cycle, and business actually picked up customers because 

traffic flows improved. The project team received several complimentary e-mails and no official 

negative feedback.
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152 

INTERSECTION PROFILE 4: US-42 AT KY-872, FLORENCE, KY

 KYTC 

Figure 122. Photo. US-42 at KY-872, Florence, Kentucky.

The junction of US-42 (Weaver Road) and KY-872 (Hopeful Church Road) is one of the busiest 

intersections in Florence, Kentucky and in August 2019 became home to the fourth QR intersection 

in the U.S. According to local officials, anyone who drives the route regularly knows the amount of 

time wasted waiting for the light to turn green. 

This $3.2 million project aims to change that. All left-turn traffic is diverted onto a newly constructed 

roadway (named Quadrant Roadway), a three-to-four lane undivided roadway that includes a midpoint access to parcels both adjacent to and inscribed by the quadrant roadway. One advantage that 

locals noted is that throughout the construction schedule during the remainder of the school year, 

impacts to commuter and bus traffic were minimal—motorists saw a lot of off-road construction but 

were only impacted during the final short changeover phase. 

Several years of study and planning went into choosing the QR intersection alternative. Studies 

considered four options, including conventional widening and turn lane improvements, a longer 

quadrant roadway utilizing an existing roadway, a two-quadrant intersection (using the southwest and 

northeast quadrants), and the selected QR intersection with its new roadway. A roundabout was also 

considered at one of the secondary T-intersections; however, a single-lane roundabout did not 

provide sufficient capacity and a multi-lane roundabout was deemed too impactful. 

Several of the factors for selecting the QR intersection alternative on the south side versus the other 

proposed alternatives included fewer access management issues, shorter projected queues and no 

major widening to either US-42 or KY-872 (only single left-turn lanes were required at each Tintersection). There were several access management issues to work out, including modifying access 

to a bank parcel. To avoid impacting a second bank parking lot, the eastbound right-turn lane on US42 was slightly shortened. The relocation of the Weaver Road entrance to the strip mall in the south 

corner was viewed as a positive by businesses within the mall. 

There were some concerns prior to opening that eastbound left turns that may cut through the strip 

mall parking lot on the northwest corner to turn on Hopeful Church Road and that the QR 

intersection may increase cut-through traffic on a nearby local street. While this did occur the week 

of opening, motorists familiar with the area quickly adapted to the new pattern which was found to 

be shorter than cut throughs once the lights were synchronized. Aligning the entrance to the strip 

mall and opposite bank access helped eliminate the left-turn conflicts. 
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153 

INTERSECTION PROFILE 5: US-220 AT CHURCH ST, GREENSBORO, NC 

This partial QR intersection application has a long history. In 1977, the City of Greensboro, 

North Carolina conducted a study to improve the congested intersection of US-220 (Wendover 

Avenue) at Church Street, seen in figure 123. Excessive intersection congestion and delay was 

being caused by a high volume of left turns from Church Street onto US-220. 

Several alternatives were considered including adding turn lanes and queue storage, conversion 

of Church Street to one-way, and the partial QR intersection. The City ultimately went with a 

partial QR intersection. The southbound Church Street left-turn movement was converted to a 

series of right turns using the existing street network. Advanced and overhead directional signs 

were used to reinforce this movement. Traffic operations were immediately improved after this 

partial QR improvement, and the PM peak hour bottleneck was immediately removed, never to 

return. 

Since 1977, traffic volumes on US-220 have risen 300 percent and left-turn volumes are 375 

percent greater. Despite the volume growth, the intersection continues to operate safety and 

efficiently. In 2007, a study was done to compute the operational benefits of the project. The 

study estimated that during the peak hour alone, there has been an estimated 2.3 million hours of 

reduced delays over the past 30 years.

 © 2019 Google Earth®

Figure 123. Photo. US-220 at Church St. Greensboro, North Carolina. 
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INTERSECTION PROFILE 6: MARKET ST AT KERR AVE, WILMINGTON, NC

The US-17 Business (Market Street) and SR 1175 (Kerr Avenue) intersection in Wilmington, 

North Carolina, seen in figure 124, was one of several intersections included in a Kerr Avenue 

Widening Study conducted in 2010. Kerr Avenue interchanges with I-40 prior to the I-40 

terminus at US-74 and is used as an alternate route to/from I-40 when the I-40/US-74 

intersection is congested. With the Kerr Avenue widening in place, intersection volumes are 

forecast from 60,000 to 75,000 vpd by 2040. Traditional intersection options were not able to 

achieve the desired LOS at this location and interchange concepts were not feasible due to cost, 

and commercial / residential impacts. As a result, a variety of alternative concepts were 

developed and a QR concept was identified as the preferred alternative to mitigate congestion. 

Multiple QR alternatives were developed for the intersection, including various roadway 

configurations in multiple quadrants. The heaviest left-turn demand was between the south and 

west legs. Eastbound drivers on Market Street would often use Cinema Drive to “cut the corner” 

to head south on Kerr Avenue, bypassing the Market Street / Kerr Avenue intersection. 

Signalizing the intersections of Cinema Drive with both Market Street and Kerr Avenue as part 

of a QR concept allowed northbound left turns to similarly “cut the corner” in the reverse 

direction. Construction of a second quadrant roadway on new alignment in the northeast 

intersection quadrant allows southbound left-turn movements to be removed from the main 

intersection.

In 2005, a single loop QR was proposed at another intersection in Wilmington; however, the 

project was put on hold due, in part, to negative public feedback over rerouting all left-turn 

movements. The community supported the Market Street / Kerr Avenue QR project because it 

only rerouted two lefts (rather than four) and did not force “right-to-go-left” movements that are 

not intuitive to drivers. To help the public understand operations and impacts, simulations were 

developed to visualize how drivers would navigate the QR intersection and explain impacts to 

commercial and residential access.

With the QR improvements in place (including both the repurposed and new quadrant roadways, 

four new signals, and lane improvements at the four secondary intersections), northbound and 

southbound left turns can be redirected, allowing the main intersection to operate with 

approximately half as much peak period delay compared to a conventional intersection. The dual 

QR concept also outperformed conventional intersection improvements during off-peak hours. In 

addition, access to businesses along each quadrant was improved by allowing road users to make 

signalized, direct left turns from the secondary intersections rather than make unsignalized 

movements.

The QR concept opened to traffic in the fall of 2018. While there was initially some driver 

confusion with the rerouted left turns, drivers have generally transitioned well into the new travel 

pattern. The City Traffic Engineer has been pleased with the operations so far and indicated that 

the dual QR intersection concept can eventually transition to reroute all four left turn movements 

in the future as the need arises.
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 NCDOT

Figure 124. Photo. Market Street at Kerr Avenue, Wilmington, North Carolina. 

QUADRANT ROADWAY INFORMATIONAL GUIDE | APPENDIX B

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APPENDIX B – MARKETING / OUTREACH MATERIALS

Several agencies have utilized brochures, videos, and fact sheets to help explain the QR 

intersection. This appendix provides the following examples of outreach materials:

Informational Flyers 

VDOT has developed an informational flyer for QR intersections and is posted on VDOT’s 

Innovative Intersections website. The flyer describes the geometric characteristics of a QR 

intersection and driving instructions, criteria for candidate locations, and the safety and 

operational benefits. The flyer can be found online at: 

http://www.virginiadot.org/images/innovate/QR_Final_082417.pdf

Educational Videos

FHWA created alternative intersection and interchange informational videos case studies, which 

can be viewed on FHWA YouTube channel. While there are no specific videos of QR 

intersections, there are many videos that explain the importance of considering alternative 

intersections when evaluating intersection improvement alternatives. Figure 125 and figure 126

illustrate examples of the type of information provided in videos on the FHWA site. 

Figure 125. Graphic. FHWA innovative intersection (RCUT) video.

Figure 126. Graphic. FHWA innovative intersection informational drive-through video.
QUADRANT ROADWAY INFORMATIONAL GUIDE | APPENDIX B

158 

Several agencies have developed educational videos as part their outreach for QR intersections 

projects. Figure 127 and figure 128 illustrate videos developed for the Huntersville, North 

Carolina and Front Royal, Virginia sites, respectively. 

Figure 127. Graphic. Example of QR intersection video developed for Front Royal project. 

Figure 128. Graphic. Example of QR intersection video developed for Huntersville project.
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159 

Examples weblinks are provided below to other project or informational QR intersection videos. 

• Huntersville Project Video: https://www.youtube.com/watch?v=ZtIL2GqQJbs

• VDOT South Forks Bridge Replacement Project Public Hearing Meeting (August 10, 2010): 

https://www.youtube.com/watch?v=NX_5q801JPg&t=1029s

• Warren County QR Project Overview: https://www.youtube.com/watch?v=D0EU07YJYC4

• Warren County QR Birds Eye: https://www.youtube.com/watch?v=HfVvqymHHjk

• Warren County QR (WB to SB): https://www.youtube.com/watch?v=SERuuezKIyU

• Warren County QR (NB to WB): https://www.youtube.com/watch?v=hzdCnETDYp0

• Generic QR Intersection Video: http://attap.umd.edu/2015/11/11/quadrant-roadway/

• E55th Opportunity Corridor Interchange: https://www.youtube.com/watch?v=Vk9Io8q_58w

VDOT has also developed an “Innovative Intersections and Interchanges” website that contains 

some useful information, brochures and videos that help explain the QR intersections found here: 

http://www.virginiadot.org/info/innovative_intersections_and_interchanges/qr.asp

https://youtu.be/eJwYLr88WsA

QUADRANT ROADWAY INFORMATIONAL GUIDE | APPENDIX C

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APPENDIX C – ARTICLES, PAPERS, AND PUBLICATIONS

Several articles, briefs, and technical papers have been written to describe the QR intersection as 

an alternative intersection concept or for a specific build or planned project. 

FHWA QR Intersection Tech Brief

The FHWA QR Intersection Tech Brief was published in 2009 and provides an overview of the 

QR Intersection that summarizes its geometric design, traffic signal control, operational 

performance, safety performance, and applicability. This publication can be found online at:

https://www.fhwa.dot.gov/publications/research/safety/09058/09058.pdf

ITE Journal Article (June 2000) 

This article introduces the QR Intersection as an alternative/innovative intersection. It explains 

scenarios where a QR Intersection could improve intersection efficiency by relocating left turns 

and therefore reducing cycle length, delay, and queue lengths. The article provides detail on the 

design considerations, traffic signal operations, comparative analysis of intersection efficiency, 

advantages, and disadvantages. The article concludes with statistics showing that QR 

Intersection improves stopped-delay and reduces system travel times (22 percent) when

compared to a traditional intersection. This publication can be found online at:

https://pdfs.semanticscholar.org/3d42/35ab4a1672edaa1ef0cea6f70cee46162a3d.pdf

APWA Reporter article (July 2013) 

This article provides four lessons learned from a QR Intersection constructed in Fairfield, OH in 

January 2012. Lesson #1 says to avoid opening before all lanes and movements can be opened to 

avoid driver confusion. Lesson #2 stated the importance of communicating the changes 

regarding driver behavior and intuition. Lesson #3 stated that left turn movement at the main 

intersection should be restricted with physical barriers. Lesson #4 notes that QR Intersections 

(and this one in particular) should be sustainable for the environment, economy, and the 

community’s health. This publication can be found online at:

https://www.apwa.net/Library/Reporter/201307_ReporterOnline.pdf

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ACKNOWLEDGEMENTS

Publication of the Quadrant Roadway (QR) Informational Guide was provided by FHWA. The 

technical writing of the guide was provided through funding from the North Carolina 

Department of Transportation. Special thanks to Kevin Lacy, State Traffic Engineer, and Joseph 

Hummer, State Traffic Management Engineer, for facilitating the funding and peer review of this 

QR Informational Guide document. 

NCDOT and its subcontractors has granted FHWA with unlimited use of all figures, graphs, and 

photos presented in this guide, unless otherwise credited in the document. 

Aerial images cited throughout the document are copyright property of Google® Earth and used 

by permission. Information on Google Earth can be accessed at https://www.google.com/earth. 

QUADRANT ROADWAY INFORMATIONAL GUIDE

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REFERENCES

1. Reid, Jonathan D. Using Quadrant Roadways to Improve Arterial Intersection 

Operations. ITE Journal, Vol. 70, No. 6, June 2000, pp. 34–36, 43–45. 

2. Partial QR Intersection. Map. Google Maps. Accessed May 1, 2019. 

https://www.google.com/maps/@35.44148,-80.86457,733m/data=!3m1!1e3 

3. Designing Walkable Urban Thoroughfares: A Context Sensitive Approach; ITE 

Publication No. RP-036A, 2010. 

4. Dual Quadrant Intersection. Map. Google Maps. Accessed May 1, 2019. 

https://www.google.com/maps/@44.0288257,-121.3165517,243m/data=!3m1!1e3

5. Four-Quadrant Intersection. Map. Google Maps. Accessed May 1, 2019. 

https://www.google.com/maps/@34.0678479,-84.1691573,1085m/data=!3m1!1e3 

6. Grade-separated single-quadrant interchange. Map. Google Maps. Accessed May 1, 

2019. https://www.google.com/maps/@39.418152,-76.7792529,265m/data=!3m1!1e3

7. Grade-separated single-quadrant interchange. Map. Google Maps. Accessed May 1, 

2019. https://www.google.com/maps/@42.5453444,-83.2840732,208m/data=!3m1!1e3 

8. American Association of State Highway and Transportation Officials (AASHTO). A 

Policy on the Geometric Design of Highways and Streets. Washington, DC: AASHTO, 

2011. 

9. Transportation Research Board. Highway Capacity Manual (HCM) 6th Edition. 

Washington, DC: TRB, National Research Council (NRC), 2018. 

10. Federal Highway Administration (FHWA). Manual on Uniform Traffic Control Devices. 

Washington, DC: U.S. Department of Transportation (USDOT), 2009. 

11. Federal Highway Administration (FHWA). Signalized Intersections: Informational 

Guide. USDOT: Washington, DC, 2013. 

12. AASHTO. Highway Safety Manual (HSM). Washington, DC: AASHTO, 2010. 

13. FHWA. Alternative Intersection/Interchanges: Informational Report (AIIR), Report No. 

FHWA-HRT-09-060. Washington, DC: USDOT, 2010. 

14. FHWA. Techbrief: Quadrant Roadway Intersection, Report No. FHWA-HRT-09-058, 

October 2009. 

15. An Update on the Quadrant Roadway Intersection; Reid, J.D; presented at the TRB 5th 

Urban Street Symposium, 2017. 

16. FHWA’s Every Day Counts Program Center for Accelerating Innovation. 

https://www.fhwa.dot.gov/innovation/everydaycounts/edc-2/geometrics.cfm 

17. https://fatpencilstudio.com/blog/traffic-simulation/ 

18. United States Access Board, Accessible Public Rights of Way webpage. 

http://www.access-board.gov/ 

19. Public Right-of-Way Accessibility Guidelines; United States Access Board publication, 

2011. 

20. FHWA Context Sensitive Solutions. U.S. Department of Transportation webpage. 

https://www.fhwa.dot.gov/planning/css/ 
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21. FHWA RCUT Informational Guide; published 2014. 

https://safety.fhwa.dot.gov/intersection/alter_design/pdf/fhwasa14070_rcut_infoguide.pdf 

22. NC-73 / US-21 Spot Safety Project Evaluation conducted by the North Carolina 

Department of Transportation; completed May 9, 2017. 

23. SR4 / SR-4 Bypass crash data provided by City of Fairfield, OH. 

24. US-340/522 at SR-55 crash data provided by Virginia Department of Transportation 

Staunton District. 

25. Federal Highway Administration (FHWA). A Guide to Developing Quality Crash 

Modification Factors. USDOT: Washington, DC, 2010. 

26. https://www.seattlebikeblog.com/2013/08/01/sdot-on-how-to-use-two-stage-left-turnboxes/ 

27. Reid, Jonathan D., and Hummer, Joseph E. Travel Time Comparisons Between Seven 

Unconventional Arterial Intersection Designs. Transportation Research Board, 

Transportation Research Record 1751, Paper No. 01-2957, 2001, pp. 56-66. 

28. Reese, Michael P., Carroll, Justin T., and Epperson, Sean M. North Carolina’s First 

Quadrant Left: History and Lessons Learned, Transportation Research Board, Paper No. 

15-2138, November 2013. 

29. FHWA Traffic Analysis Toolbox. 

www.fhwa.dot.gov/publications/research/infrastructure/pavements/ltpp/04038/index.cfm 

30. Transportation Systems Institute. Capacity Analysis for Planning of Junctions (CAP-X). 

Version 1.2 (2011). http://tsi.cecs.ucf.edu/index.php/cap-x 

31. VJUST analysis tool. 

http://www.virginiadot.org/business/resources/LocDes/01_VJuST_Ver1.02.xlsm 

32. FHWA’s Traffic Analysis Tools website: 

https://ops.fhwa.dot.gov/trafficanalysistools/index.htm 

33. Joseph Hummer, Michael Reece and Bailey Harden. The Potential of a Seven-Phase 

Signal to Provide Access without Sacrificing Mobility. Institute of Transportation 

Engineers Journal. January 2019, pp 38-42. 

34. https://www.seattlebikeblog.com/2013/08/01/sdot-on-how-to-use-two-stage-left-turnboxes/

35. Mann, Ben and Hoying, Daniel. Alternative Intersection Design Delivers. APWA 

Reporter. July 2013, pp. 60-63.