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This report complements the American association of State Highway and Transportation Officials' (AASHTO) Strategic Highway Safety Plan to develop guidance on safety of nonsignalized and signalized intersections. The goal is to reduce the annual number of highway deaths. This guide is a comprehensive document that contains methods for evaluating the safety and operations of signalized intersections and tools to remedy deficiencies. The treatments in this guide range from low-cost measures such as improvements to signal timing and signage, to high-cost measures such as intersection reconstruction or grade separation. Topics covered include fundamental principles of user needs, geometric design, and traffic design and operation; safety and operational analysis techniques; and a wide variety of treatments to address existing or projected problems, including individual movements and approaches, pedestrian and bicycle treatments, and corridor techniques. It also includes coverage of alternative intersection forms that improve intersection performance through the use of indirect left turns and other treatments. Each treatment includes a discussion of safety, operational performance, multimodal issues, and physical and economic factors that the practitioner should consider. Although the guide has considerable focus on high-volume signalized intersections, many treatments also are applicable for lower volume intersections. The information contained in this guide is based on the latest research on available treatments and best practices in use by jurisdictions across the United States. Additional resources and references are highlighted for the student, practitioner, researcher, or decisionmaker who wishes to learn more about a particular subject.
Copies of this report may be obtained from the Research and technology Report Center, 9701 Philadelphia Court, Unit Q, Lanham, MD 20706; telephone: 301–577–0818; fax: 301–577–1421; or the National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161; telephone: 703–487–4650; fax: 703–321–8547.
Michael F. Trentacoste
Director
Office of Safety Research and Development
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 its contents or use thereof. This report does not constitute a standard, specification, or regulation.
The U.S. Government does not endorse products or manufacturers. Trade and manufacturers’ names appear in this report only because they are considered essential to the object of this 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.
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7. Author(s) Principal Investigator: Lee A. Rodegerdts Co-Investigators: Brandon Nevers, Bruce Robinson Co-Authors: John Ringert, Peter Koonce, Justin Bansen, Tina Nguyen, John McGill, Del Stewart, Jeff Suggett, Tim Neuman, Nick Antonucci, Kelly Hardy, Ken Courage |
8. Performing Organization Report No. Project 4770 |
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9. Performing Organization Name and Address Kittelson & Associates, Inc. Subconsultants: Synectics transportation Consultants, Inc.; CH2M Hill, Inc.;
and Ken Courage |
10. Work Unit No. (TRAIS)
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11. Contract or Grant No. Contract No. DTFH61-98-C-00075, |
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12. Sponsoring Agency Name and Address Federal Highway Administration |
13. Type of Report and Period Covered Informational Guide Book
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14. Sponsoring Agency Code |
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15. Supplementary Notes Joe G. Bared (Joe.Bared@fhwa.dot.gov) at the turner-Fairbank Highway Research Center (http://www.tfhrc.gov) was the technical Representative for the Federal Highway Administration (FHWA). Project focus group members contributed significantly to document organization, content, and exhibits: Tom Hicks, Maryland State Highway Administration; Nick Kalivoda, Louisiana Department of Transportation; Nazir Lalani, Ventura County (California); John Mason, Pennsylvania State University; and brian Walsh, Washington State Department of Transportation. In addition, many FHWA staff members participated as focus group members and/or provided comments throughout the project, including Carl Andersen, David Gibson, Hari Kalla, Ray Krammes, Barbara McMillen, Bill Prosser, fred Ranck, Tamara Redmon, Essie Wagner, and Scott Wainwright. |
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16. Abstract This guide provides a single, comprehensive document with methods for evaluating the safety and operations of signalized intersections and tools to remedy deficiencies. The treatments in this guide range from low-cost measures such as improvements to signal timing and signage, to high-cost measures such as intersection reconstruction or grade separation. Topics covered include fundamental principles of user needs, geometric design, and traffic design and operation; safety and operational analysis techniques; and a wide variety of treatments to address existing or projected problems, including individual movements and approaches, pedestrian and bicycle treatments, and corridor techniques. It also covers alternative intersection forms that improve intersection performance through the use of indirect left turns and other treatments. Each treatment includes a discussion of safety, operational performance, multimodal issues, and physical and economic factors that the practitioner should consider. Although the guide focuses primarily on high-volume signalized intersections, many treatments are applicable for lower volume intersections as well. The information contained in this guide is based on the latest research available on treatments and best practices in use by jurisdictions across the United States. Additional resources and references are highlighted for the student, practitioner, researcher, or decisionmaker who wishes to learn more about a particular subject. |
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18. Distribution Statement
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19. Security Classif. (of this report) |
20. Security Classif. (of this page) |
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Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
1.4 Organization of the Guidelines
PART I FUNDAMENTALS
2.2.1 Human Factors Common to All Road Users
3.2 Number of Intersection Legs
3.4 Horizontal and Vertical Alignment
3.5 Corner Radius and Curb Ramp Design
3.6.3 Intersection Sight Distance
4.0 TRAFFIC DESIGN AND ILLUMINATION
4.1 Traffic Signal Control Type
4.2.1 "Permissive-Only" Left-Turn phasing
4.2.2 "Protected-Only" Left-Turn phasing
4.2.3 Protected-Permissive Left-Turn phasing
4.2.5 Prohibited Left-Turn phasing
4.3 Vehicle and Pedestrian Displays
4.4 Traffic Signal Pole Layout
4.7 Basic Signal Timing parameters
4.7.2 Vehicle timing—Green interval
4.7.3 Vehicle timing—Detector Timing
4.7.4 Vehicle timing—Vehicle Clearance
4.7.5 Vehicle timing—Cycle Length
4.8 Signing and Pavement Marking Design
PART II PROJECT PROCESS ANALYSIS METHODS
5.2 Identify Stakeholder Interests and Objectives
5.2.2 Adjacent Property/Business owners
5.4.1 Establish Performance Measures and Criteria
5.4.2 Summarize Operational and Safety Conditions
5.4.3 Develop Problem Statement
5.6.1 Identify Range of Treatments
5.6.3 Assess Potential To Introduce Undesirable Effects
5.6.4 Determine Costs and Implementation issues
6.1 Balancing Safety and Mobility
6.2 Selection of an intersection
6.2.3 Combined Collision Frequency and Rate Method
6.2.4 Collision Severity Method
6.2.7 Safety Performance Functions
6.3 Identification of Potential Problems
6.3.3 Analyze/Diagnose Collision Data
6.3.4 Determine Overrepresentation
6.3.6 Deciding on Further Analysis
6.3.7 Conducting Further Studies
6.3.8 Defining the Problem Statement
6.4 Identification of Possible Treatments
6.4.1 List Possible Treatments
6.4.3 Selecting a Collision Modification Factor or Study Finding
6.5 Improvement Plan Development
7.0 OPERATIONAL ANALYSIS METHODS
7.1 Operational measures of Effectiveness
7.1.1 Motor Vehicle Capacity and Volume-to-Capacity Ratio
7.1.2 Motor vehicle Delay and Level of Service
7.1.4 Transit Level of Service
7.1.5 Bicycle Level of Service
7.1.6 Pedestrian Level of Service
7.2 Traffic Operations Elements
7.2.1 Traffic Volume Characteristics
7.3 Rules of Thumb for Sizing an intersection
7.4 Critical movement analysis
7.5 HCM Operational Procedure for Signalized Intersections
7.6 Arterial and Network Signal Timing Models
7.7 Microscopic Simulation Models
PART III TREATMENTS
8.1.9 Enforcement, Education, and maintenance
8.2.9 Enforcement, Education, and maintenance
8.3.8 Enforcement, Education, and maintenance
8.4 Signal Preemption and/or Priority
8.4.2 Emergency Vehicle Preemption
8.4.9 Enforcement, Education, and Maintenance
9.0 INTERSECTION-WIDE TREATMENTS
9.1.3 Modify Stop Bar Location
9.1.4 Improve Pedestrian Signal Displays
9.1.5 Modify Pedestrian Signal Phasing
9.1.6 Grade-Separate Pedestrian Movements
9.4 Traffic Control Treatments
9.4.1 Change signal Control from Pre-Timed to Actuated
9.4.2 Modify Yellow Change interval and/or Red Clearance interval
9.4.4 Late Night/Early Morning Flash Removal
9.5 Street Lighting and Illumination
9.5.1 Provide or Upgrade illumination
10.0 ALTERNATIVE INTERSECTION TREATMENTS
10.1 Intersection Reconfiguration and Realignment treatments
10.1.1 Remove intersection Skew Angle
10.1.2 Remove Deflection in Travel Path for Through Vehicles
10.1.3 Convert four-Leg Intersection to Two T-Intersections
10.1.4 Convert two T-Intersections to Four-Leg Intersection
10.2 Indirect Left-Turn Treatments
10.2.2 Median U-Turn Crossover
10.2.3 Continuous Flow Intersection
10.2.4 Quadrant Roadway intersection
10.2.5 Super-Street Median Crossover
10.3 Grade-Separation Treatments
11.1 Signal Head Placement and Visibility
11.1.1 Convert to Mast arm or Span Wire Mounted Signal Heads
11.1.2 Add Near-Side signal Heads
11.1.3 Increase size of Signal Heads
11.1.4 Use two Red Signal Sections
11.1.5 Increase Number of Signal Heads
11.1.7 Provide Advance Warning
11.2 Signing and Speed Control Treatments
11.3 Roadway Surface Improvements
11.3.1 Improve Pavement Surface
11.3.4 Remove Obstacles from Clear Zone
11.4 Sight Distance Treatments
12.0 INDIVIDUAL MOVEMENT TREATMENTS
12.1.1 Add Single Left-Turn Lane
12.1.2 Multiple Left-Turn Lanes
12.2.1 Provide Auxiliary Through Lanes
12.3.1 Add Single Right-Turn Lane
12.3.2 Provide Double Right-Turn Lanes
12.3.3 Provide Channelized Right-Turn Lane
12.4 Variable Lane Use Treatments
12.4.1 Provide Reversible Lanes
12.4.2 Provide Variable Lane Use Assignments
BIBLIOGRAPHY (OTHER REFERENCES)
CHAPTER 2
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2 |
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3 |
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4 |
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5 |
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6 |
Examples of pedestrians of various abilities preparing to cross an intersection |
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8 |
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9 |
Pedestrian conflicts at signalized intersections |
CHAPTER 3
CHAPTER 4
CHAPTER 6
CHAPTER 7
CHAPTER 8
CHAPTER 9
CHAPTER 10
CHAPTER 11
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Signal head with a double red signal indication |
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114 |
Lane-aligned signal heads |
115 |
Illustration of sight distance triangles |
CHAPTER 12
LIST OF TABLES
CHAPTER 1
1 |
Summary of motor vehicle crashes related to junction and severity in the United States during 2002 |
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2 |
Organization of the guide |
3 |
CHAPTER 2
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5 |
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6 |
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Proportion of crashes by collision type at signalized intersections |
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Typical dimensions for a sample of types of pedestrians |
CHAPTER 3
CHAPTER 4
CHAPTER 5
CHAPTER 6
CHAPTER 7
CHAPTER 8
CHAPTER 9
CHAPTER 10
CHAPTER 11
CHAPTER 12
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