Overview of Signalized Intersections

Length: Approximately 8 hours

Description

This course introduces the key concepts, parameters, and processes used in modern traffic signal timing. Students will explore detector-based controller operations (including recall modes, gap timing, and volume-density functions), coordinated timing principles across multiple intersections (such as cycle length, offsets, and bandwidth), and the step-by-step development of timing plans—from defining the project scope to implementation in the field. The course also highlights multimodal considerations and integrates pedestrian, bicycle, and transit needs into timing decisions, emphasizing a holistic system-wide approach to corridor operations.

Objectives

Upon completion of this course, participants will be able to:

Discuss the fundamental concepts that underlie traffic signal timing.
Identify the different types of traffic control signals and their operating characteristics.
Define common Measures of Effectiveness (MOEs) used in evaluating traffic signal performance, such as delay, travel time, and volume-to-capacity ratios.
List the key steps in developing a signal timing plan.
Recognize how traffic signal timing fits into broader corridor and system operations, including multimodal considerations.

Outline (click to display)

The course outline is as follows:

Lesson 1: Introduction to Intersections
• Intersection Control Basics
-Using the Manual on Uniform Traffic Control Devices (MUTCD)
-Traffic Signal Warrants
-Engineering Studies
-Traffic Signal Life Cycle

Lesson 2: Signalized Intersection Operations Analysis
• Intersection Analysis
-Headway and Gap
-Estimating Capacity
• Critical Movement Analysis
-Critical Pairs
-Phases, Rings, Barriers
• Highway Capacity Manual (HCM) Intersection Analysis
-HCM Capacity Definition
-Saturation Flow Rate
• Time Within a Phase
-Green Time
-Effective Green Time
-Lost Time

Lesson 3: Signal Equipment Fundamentals
• Signal Displays
-Vehicle Displays
-Pedestrian Displays
• Traffic Controller Cabinets
-Controller Cabinet Locations
-Controller Cabinet Types
• Detection
-Detection Uses
-Detection Types

Lesson 4: Signal Timing Basics Part 1
• Movements and Phases
-Movement and Phase Numbering
-Ring and Barrier Diagram
-Movement and Phase Diagram
• Basic Signal Timing Parameters
-Yellow Change Interval
-Red Clearance
-Minimum Green Time
-Maximum Green Time
-Pedestrian Intervals

Lesson 5: Signal Timing Basics Part 2
• Left-Turn Phasing
-Permitted
-Protected
-Protected-Permitted
• Split Phasing
• Overlaps

Lesson 6: Detection
• Modes of Operations
-Fixed Time
-Semi-Actuated
-Fully Actuated
• Detection Placement
-Typical Locations
-Decision Zones
• Signal Timing Parameters
-Passage Time
-Delay
-Extend

Lesson 7: Detection Based Controller Settings
• Recall Modes
-Minimum Recall
-Maximum Recall
-Pedestrian Recall
• Gap Settings
• Volume Density Timing Parameters

Lesson 8: Coordinated Timing Concepts
• Coordinated Operations Basic Concepts
• Time-Space Diagram
• Offset
• Bandwidth
• Communication

Lesson 9: Developing a Timing Plan
• Signal Timing Plan Development
-Work Scope Definition
-Objectives
-Define Study Corridor
-Data Collection
-Timing Plan Model
-Signal Timing Methodology
-Measures of Effectiveness (MOE)
-Field Implementation

Lesson 10: Multimodal Considerations
• Multimodal Process
• Multimodal Considerations
• Pedestrian Design Elements
• Bicycle Design Elements
• Transit Treatments

Contributor(s)

Kevin Lee
Founder & Principal, Illumine Transportation