Traffic Signal Timing Manual

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Contact Information: Eddie Curtis at Eddie.Curtis@dot.gov

Table of Contents

Notice

Documentation Page

• 1.0 INTRODUCTION
• 1.1 BACKGROUND
  • 1.1.1 Purpose of Traffic Signals
  • 1.1.2 Intersection Design and its Relationship to Signal Timing
  • 1.1.3 Objectives of Basic Signal Timing Parameters and Settings
  • 1.1.4 Establishing the Need for Retiming
  • 1.1.5 Benefits of Up-to-Date Timing
• 1.2 ORGANIZATION OF THE MANUAL
• 1.3 USE OF THE MANUAL
• 1.4 REFERENCES

• 2.0 SIGNAL TIMING POLICY
• 2.1 Policy Development
  • 2.1.1 Policy Influence on Signal Timing
  • 2.1.2 Challenges to Signal Timing Policy Development
  • 2.1.3 Use of Standards
• 2.2 Signal Timing Process
  • 2.2.1 Signal Timing Maintenance and Data Management
  • 2.2.2 Hardware and Software Considerations
  • 2.2.3 Selection of Optimization Tools and Evaluation of Policies
  • 2.2.4 Other Policy Considerations
• 2.3 Performance Measures and National Perspective in Signal Timing
  • 2.3.1 National Traffic Signal Report Card
  • 2.3.2 National Signal Timing Findings
• 2.4 Funding Considerations
  • 2.4.1 Direct Signal Timing Funding
  • 2.4.2 Partnerships for Funding Signal Timing
• 2.5 Examples of Programs
• 2.6 References

• 3.0 OPERATIONAL AND SAFETY ANALYSIS
• 3.1 Terminology
• 3.2 Characteristics Affecting Signal Timing
  • 3.2.1 Location
  • 3.2.2 Transportation Network Characteristics
  • 3.2.3 Intersection Geometry
  • 3.2.4 User Characteristics
• 3.3 Capacity and Critical Movement Analysis
  • 3.3.1 Basic Operational Principles
  • 3.3.2 Saturation Flow Rate
  • 3.3.3 Lost Time
  • 3.3.4 Capacity
  • 3.3.5 Volume-to-Capacity Ratio
  • 3.3.6 Critical Movement Analysis
• 3.4 Intersection-Level Performance Measures and Analysis Techniques
  • 3.4.1 Performance Measures
  • 3.4.2 Evaluation Techniques: The HCM Procedure for Signalized Intersections
  • 3.4.3 Practical Operational Approximations
  • 3.4.4 Intersection-Level Field Measurement
• 3.5 Arterial- and Network-Level Performance Measures and Prediction Techniques
  • 3.5.1 Arterial- and Network-Level Performance Measures
  • 3.5.2 Evaluation Techniques
  • 3.5.3 Arterial and Network Field Measurement Techniques
• 3.6 Safety Assessment
  • 3.6.1 Crash Data Review
  • 3.6.2 Quantitative Safety Assessment
• 3.7 Signal Warrants
• 3.8 References

• 4.0 TRAFFIC SIGNAL DESIGN CONCEPTS
• 4.1 Overview
  • 4.1.1 Relationship between Signal Timing and Traffic Control Design
  • 4.1.2 Traffic Signal System Design
• 4.2 Phasing Overview
  • 4.2.1 Definitions and Terminology
  • 4.2.2 Ring-and-Barrier Diagrams
• 4.3 Left-Turn Display Options
  • 4.3.1 Permissive Only Left-Turn Phasing
  • 4.3.2 Protected Only Left-Turn Phasing
  • 4.3.3 Protected-Permissive Left-Turn Phasing
  • 4.3.4 Split Phasing
  • 4.3.5 Prohibition of Left-Turns as a Phasing Option
  • 4.3.6 Guidelines for Selecting Left-Turn Phasing
• 4.4 Left-Turn Phase Sequence Options
  • 4.4.1 Lead-Lead Left-Turn Phase Sequence
  • 4.4.2 Lag-Lag Left-Turn Phase Sequence
  • 4.4.3 Lead-Lag Left-Turn Phase Sequence
• 4.5 Pedestrian Phasing
• 4.6 Right-Turn Phasing
• 4.7 Detection Fundamentals
  • 4.7.1 Detection Design Objectives
  • 4.7.2 Detector Operating Modes
  • 4.7.3 Controller Memory Modes
  • 4.7.4 Detection Design for High-Speed Approaches
  • 4.7.5 Detection Design for Low-Speed Traffic Movements
• 4.8 Detection Applications
  • 4.8.1 Basic Fully-Actuated Design
  • 4.8.2 Volume-Density Design
  • 4.8.3 Multiple-Detector Design
  • 4.8.4 Left-Turn Movements
  • 4.8.5 Right-Turn Movements
• 4.9 References

• 5.0 BASIC SIGNAL TIMING PROCEDURE AND CONTROLLER PARAMETERS
• 5.1 Terminology and Key Definitions
• 5.2 Modes of Traffic Signal Operation and Their Use
  • 5.2.1 Pre-timed Control
  • 5.2.2 Semi-Actuated Control
  • 5.2.3 Fully-Actuated Control
• 5.3 Phase Intervals and Basic Parameters
  • 5.3.1 Vehicular Green Interval
  • 5.3.2 Vehicular Change and Clearance Intervals
  • 5.3.3 Pedestrian Timing Intervals
• 5.4 Actuated Timing Parameters
  • 5.4.1 Phase Recalls
  • 5.4.2 Passage Time
  • 5.4.3 Simultaneous Gap
  • 5.4.4 Dual Entry
• 5.5 Volume-Density Features
  • 5.5.1 Gap Reduction
  • 5.5.2 Variable Initial
• 5.6 Detection Configuration and Parameters
  • 5.6.1 Delay
  • 5.6.2 Extend
  • 5.6.3 Carryover
  • 5.6.4 Call
  • 5.6.5 Queue
• 5.7 Guidelines for Time-Base Controls
• 5.8 References

• 6.0 COORDINATION
• 6.1 Terminology
• 6.2 Principles of Coordinated Operation
  • 6.2.1 Coordination Objectives
  • 6.2.2 When to Use Coordination
  • 6.2.3 Fundamentals of Coordination
  • 6.2.4 Summary
• 6.3 Coordination Mechanics
  • 6.3.1 Cycle Length
  • 6.3.2 Yield Point
  • 6.3.3 Splits
  • 6.3.4 Offsets
  • 6.3.5 Other Coordination Settings
  • 6.3.6 Pre-timed and Actuated Comparison
• 6.4 Time-Space Diagram
  • 6.4.1 Basic Concepts (Time, Distance, Speed, and Delay)
  • 6.4.2 Left-Turn Phasing
  • 6.4.3 Bandwidth
• 6.5 Transition Logic
  • 6.5.1 Example Application of Time Based Coordination Transition
  • 6.5.2 Transition Modes
  • 6.5.3 Operational Guidelines
• 6.6 Coordination Timing Plan Guidelines
  • 6.6.1 Coordinated Phase Assignment
  • 6.6.2 Cycle Length Selection
  • 6.6.3 Split Distribution
  • 6.6.4 Offset Optimization
• 6.7 Coordination Complexities
  • 6.7.1 Hardware Limitations
  • 6.7.2 Pedestrians
  • 6.7.3 Phase Sequence
  • 6.7.4 Early Return to Green
  • 6.7.5 Heavy Side Street Volumes
  • 6.7.6 Turn Bay Interactions
  • 6.7.7 Critical Intersection Control
  • 6.7.8 Oversaturated Conditions
• 6.8 REFERENCES

• 7.0 DEVELOPING SIGNAL TIMING PLANS
• 7.1 OVERVIEW
  • 7.1.1 Signal Timing Process
  • 7.1.2 Frequency of Timing Updates
  • 7.1.3 Steps
• 7.2 Project Scoping
  • 7.2.1 Determine Objectives based on Signal Timing Policies
  • 7.2.2 Confirm Standards and Procedures
  • 7.2.3 Dividing the System into Sections
  • 7.2.4 Select Performance Measures
  • 7.2.5 Identify the Number of Timing Plans
• 7.3 Data Collection
  • 7.3.1 Traffic Volumes
  • 7.3.2 Intersection Geometry and Control
  • 7.3.3 Field Review
  • 7.3.4 Existing Signal Timing
  • 7.3.5 Intersection Analysis
• 7.4 Model Development
  • 7.4.1 Data Input
  • 7.4.2 Analysis
  • 7.4.3 Draft Timing Plans
  • 7.4.4 Final Timing Plans
• 7.5 Field Implementation and Fine Tuning
• 7.6 Evaluation of Timing
  • 7.6.1 Performance Measurement
  • 7.6.2 Policy Confirmation and Reporting
• 7.7 References

• 8.0 SIGNAL TIMING MAINTENANCE: OPERATIONS AND MONITORING
• 8.1 Overview
• 8.2 Traffic Signal Operations
  • 8.2.1 Signal Timing Maintenance Activities
  • 8.2.2 Reasons for Signal Timing Maintenance
• 8.3 Day-to-Day Operations
  • 8.3.1 Signal Retiming
  • 8.3.2 Signal Timing Inventory
  • 8.3.3 Staff Training
  • 8.3.4 Responding to Citizen Calls
  • 8.3.5 Incident Management and Planned Special Events
• 8.4 Staffing Needs
  • 8.4.1 Background Information
  • 8.4.2 Staff Positions and Roles
  • 8.4.3 Staff Needs
• 8.5 References

• 9.0 ADVANCED SIGNAL TIMING CONCEPTS
• 9.1 Traffic Signal Preemption
  • 9.1.1 Preemption Overview
  • 9.1.2 Effect on Signal Timing
  • 9.1.3 Example Applications
• 9.2 Traffic Signal Priority
  • 9.1.4 Traffic Signal Priority Overview
  • 9.1.5 Effect on Signal Timing
  • 9.1.6 Examples of Transit Signal Priority
• 9.3 Traffic Responsive Operation
  • 9.1.7 Traffic Responsive Overview
  • 9.1.8 Techniques - Operational
• 9.4 Adaptive Traffic Signal Control
  • 9.1.9 Adaptive Traffic Signal Control Overview
  • 9.1.10 Adaptive Control Concepts
  • 9.1.11 Examples of Adaptive Traffic Control Systems
• 9.5 Planned Special Events, Incident, & Emergency Management
  • 9.1.12 Overview
  • 9.1.13 Techniques – Operational
  • 9.1.14 Policy/Institutional Strategies
  • 9.1.15 Example Implementations
• 9.6 Weather-Related Factors that Influence Signal Timing
  • 9.1.16 Weather-Related Factors Overview
  • 9.1.17 Techniques – Operational
• 9.7 References

1200 New Jersey Avenue, SE
Washingtion, DC 20590

June 2008

Publication Number: FHWA-HOP-08-024

Task Order Under Contract Number: DTFH61-98-C-00075