Federal Hig

hway Administration Operations Research and Development

Saxton Transportation Operations Laboratory

Traffic Bottlenecks

Identification and Diagnosis, Countermeasure Prioritization, and

Innovative Solutions to Local/Systemic Problems

Background

Often entire regions are overwhelmed by increasing traffic demand and 

limited ability to implement expensive systemic improvements to mitigate 

congestion. In 2010 alone, the estimated cost of congestion was $101 billion.

1

In recent years, the Federal Highway Administration (FHWA) has 

led research efforts and produced publications related to congestion 

identification, diagnosis, and mitigation. Through these efforts, FHWA has 

found that a large percentage of traffic congestion results from recurring 

causes, including bottlenecks. Due to rising costs related to congestion, it 

is important to diagnose and identify cost-effective bottleneck solutions; 

however, the current body of knowledge surrounding traffic congestion is 

dated and in need of updating and revision. Some recurring congestion 

occurs at specific locations on the highway system, where periodic volume 

surges coupled with roadway geometrics overwhelm the physical capacity 

of roadway segments, creating traffic bottlenecks. Transportation agencies 

have observed that traffic bottlenecks can be alleviated using low-cost 

and cost-effective solutions, resulting in a better benefit-cost ratio than 

more expensive infrastructure investments. Therefore, research and analysis 

efforts toward developing and evaluating low-cost and cost-effective traffic 

bottleneck solutions are promising. 

The existing research does not clearly separate causes of recurring 

congestion into categories needed to identify causalities. This project aims 

to provide guidance on the characteristics of congestion and bottlenecks 

that occur on a facility level; to investigate existing innovative and 

cost-effective solutions to bottlenecks; and to disseminate information 

to researchers and practitioners for practical use in combating traffic 

congestion and bottlenecks.

Project Objectives • Define congestion. • Develop a prototype application for agencies to identify congestion. • Explore and refine a “Causes of Congestion” pie chart. • Disaggregate recurring congestion into localized and systemic. • Disaggregate recurring congestion occurring on freeways and surface 

streets.

• Provide technical guidance for congestion and bottleneck identification, 

diagnosis, classification, and applied solutions.

• Develop innovative and cost-effective solutions for bottleneck problems 

(permanently installed and dynamically triggered).

• Develop examples of cost-benefit analysis techniques using the Tool for 

Operations Benefit/Cost (TOPS-BC).

• Provide examples of techniques to prioritize bottlenecks. • Develop workshop materials and research papers. 1 Schrank, D., T. Lomax, and B. Eisele, 2011 Urban Mobility Report. Texas

 Transportation Institute, September 2011. Available at http://mobility.tamu.edu 2 Influencing demand and capacity 3 Combination of traffic volumes and composition as sole cause, no other influencing causes

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Federal Highway Administration Operations Research and Development

Saxton Transportation Operations Laboratory

Project Overview by Task

• Task 1: Project Management and Work Plan – The research team will conduct a 

kickoff meeting, build a focus or advisory group, develop the work plan, and provide 

continuous project management throughout the duration of the project.

• Task 2: Synthesis of Research and Findings – The research team will perform a literature 

review of relevant studies on recurring congestion, bottleneck studies in particular. The 

team will identify limitations and gaps in the current methodologies for congestion 

problem identification, diagnosis, and analysis; and will further identify possible unique 

styles of congestion diagnosis and analysis procedures nationwide. Next, they will 

develop a taxonomy scheme for bottlenecks and corresponding solutions.

• Task 3: Problem Identification and Classification – The research team will measure the 

sources of congestion and adjust or confirm the existing “Causes of Congestion” pie 

chart. The team will identify metropolitan planning organizations (MPOs) to provide 

archived and real-time traffic datasets for analysis and will disaggregate recurring 

congestion and will define and classify bottlenecks based on that data. Next, the team 

will propose solutions for bottlenecks and provide guidelines to regional and local 

agencies on recurring congestion analysis with a special focus on bottlenecks.

• Task 4: Solutions for Typical Bottleneck Problems – The research team will perform 

traffic simulation of bottleneck solutions; perform benefit-cost analysis to determine 

cost-effective bottleneck solutions; develop guidelines for agencies with current 

bottleneck programs; prepare a research paper based on the findings of Tasks 2 and 3; 

develop workshop materials; and conduct three workshops on bottleneck diagnostics 

and cost-effective solutions. 

• Task 5: Cost-Effective Solutions for Typical Bottleneck Problems – Using the resulting 

materials from Tasks 1 through 4, the research team will identify major gaps in existing 

cost-effective solutions for bottleneck congestion problems and will develop innovative, 

cost-effective solutions for bottlenecks. Solutions will fall into one of two categories:

• Cost-effective solutions to delay or prevent onset of bottlenecks (dynamically 

triggered).

• Cost-effective solutions to alleviate or eliminate congestion due to bottlenecks 

(permanently installed).

• Task 6: Conduct Research for Selected Cost-Effective and Innovative Bottleneck 

Solutions – In Task 6, the research team will further develop selected innovative,

cost-effective bottleneck solutions with the highest potential congestion relief impact.

Engagement with 

Stakeholders

Inform – Provide effective 

marketing and outreach material 

outlining ongoing congestion 

and bottleneck research. 

Educate – Provide new 

and existing information on 

congestion and bottlenecks to 

State and local agencies and 

transportation professionals.

Interact – Generate effective 

outreach efforts to allow 

practitioners and researchers 

opportunities to interact and 

discuss problems and solutions 

surrounding congestion and 

bottelenecks.

Influence – Create opportunities 

for diverse groups to influence 

development of new and 

innovative solutions to reduce 

congestion and bottlenecks.

Collaborate – Provide a 

platform for collaboration 

among various groups with an 

interest in reducing congestion 

and bottlenecks through costeffective solutions.

Partner – Work with various 

agencies and individuals to 

identify diverse solutions to 

congestion and bottlenecks.

For more information on the 

project, please contact:

Joe Bared, FHWA

202-493-3314

joe.bared@dot.gov

Randy VanGorder, FHWA

202-493-3266

randall.vangorder@dot.gov

Publication No.: FHWA-HRT-13-082

July 2013 HRDO-60/07-13(200)E