Office of Operations
21st Century Operations Using 21st Century Technologies

Recurring Traffic Bottlenecks: A Primer
Focus on Low-Cost Operational Improvements (Fourth Edition)

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U.S. Department of Transportation
Federal Highway Administration
Office of Operations
1200 New Jersey Avenue, SE
Washington, DC 20590


November 2017

Table of Contents

Chapter 1. Introduction

When Did "Plan on Being Delayed" Become Part of Our Everyday Lexicon?

Purpose of the Primer

Why Focus on Bottlenecks?

Chapter 2. Understanding Bottlenecks

What Exactly is a "Traffic Bottleneck?"

How Are Bottlenecks Monitored and Measured?

Understanding Merging at Recurring Bottlenecks

Merge Principles

Which Is Best? "Early" or "Late" Merging?

Principles Put into Practice: Variable Speed Limits and Speed Harmonization

Is Murphy Right? Does the Other Lane "Always Move Faster"?

Chapter 3. Dealing With Bottlenecks Programmatically

What is the Federal Highway Administration Doing to Mitigate Bottlenecks?

Benefits of Localized Bottleneck Reduction Strategies

Chapter 4. How to Structure a Localized Bottleneck Program

What is Stopping Us from Fixing Bottlenecks?

Overcoming Challenges to Implementing Localized Bottlenecks Reduction Projects

Ideas for Structuring a Localized Bottleneck Reduction Program

Potential Issues with Localized Bottleneck Reduction Treatments

Chapter 5. Analytical Identification and Assessment of Bottlenecks

Where Are the Bottlenecks and How Severe Are They?

Recent Advances in Data and Analytics for Bottleneck Assessment

Chapter 6. Localized Bottleneck Reduction Strategies

Types of Localized Bottleneck Reduction Treatments

Advanced Forms of Bottleneck Treatments Already In Practice

Chapter 7. Emerging Bottleneck Treatments

Dynamic Hard Shoulder Running

Dynamic Reversible Left Turn Lanes

Contraflow Left Turn Pockets

Chapter 8. Success Stories: How Agencies are Developing Localized Bottleneck Reduction Programs

Successful Localized Bottleneck Reduction Program Development

Successful Localized Bottleneck Reduction Applications

Want More Information?

Appendix A. Additional Principles on Traffic Flow and Bottlenecks

Shock Waves and the Accordion Effect: The Movement of Queues on Freeways

Appendix B. Traffic Bottleneck Typology

Appendix C. Case Studies






Appendix D. Definitions and Traffic Bottleneck Typologies

List of Figures

Figure 1. Chart. Common locations for localized bottlenecks.

Figure 2. Infographic. Overview of Maryland's I‑270 Upgrade Project.

Figure 3. Photo. Cover of Federal Highway Administration's Traffic Bottlenecks: Identification and Solutions report.

Figure 4. Simulation graphics. Typical Section of MN I‑35W Northbound Priced Dynamic Shoulder Lane (PDSL)

Figure 5. Photo. Cover of Federal Highway Administration's An Agency Guide on Overcoming Unique Challenges to Localized Congestion Reduction Projects.

Figure 6. Flow chart. Minnesota Department of Transportation project screening process.

Figure 7. Graph. Speed contours over time and space showing bottleneck locations.

Figure 8. Map. Using vehicle probe data for bottleneck analysis.

Figure 9. Matrix. Spatiotemporal Traffic Matrix (STM).

Figure 10. Chart. Using the variability in delay to prioritize bottlenecks.

Figure 11. Schematic. Example of dynamic lane grouping at a signalized intersection.

Figure 12. Simulation graphic. Dynamic junction control implementation.

Figure 13. Schematic. Vehicular movements at a continuous flow intersection.

Figure 14. Schematic. Crossover movement in a double crossover diamond (DCD) interchange

Figure 15. Schematic. Median U-turn (MUT) intersection.

Figure 16. Schematic. Restricted crossing U-turn (RCUT) intersection.

Figure 17. Photo. U.S. Route 17 restricted crossing U-turn intersection corridor in Leland, North Carolina.

Figure 18. Schematic. The quadrant roadway (QR) intersection.

Figure 19. Map. Success spawns success: Virginia's Strategically Targeted Affordable Roadway Solutions (STARS) program spurs Rhode Island to develop its own STARS Program

Figure 20. Traffic backed up on northbound Wadsworth prior to the project. Restaurant (blue roof) had to be relocated.

Figure 21. The new Grandview Bridge, "Gateway to Olde Arvada."

Figure 22. A ramp meter.

Figure 23. The sign for U.S. 183.

Figure 24. Moving Washington logo.

List of Tables

Table 1. The 10 worst physical bottlenecks in the United States.

Table 2. Examples of how agencies have addressed localized bottleneck issues.

Table 3. Reliability prediction methods developed by the Strategic Highway Research Program 2 program.

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