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21st Century Operations Using 21st Century Technologies

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



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 the use of the information contained in this document. This report does not constitute a standard, specification, or regulation.

The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers' names may appear in this report only because they are considered essential to the objective of the 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 for continuous quality improvement.

Technical Report Documentation Page

1. Report No.


2. Government Accession No.

3. Recipient's Catalog No.

4. Title and Subtitle

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

5. Report Date

November 2017

6. Performing Organization Code

7. Author(s)

Neil Spiller, Katherine Blizzard, Rich Margiotta, Ph.D.

8. Performing Organization Report No.

9. Performing Organization Name and Address

Cambridge Systematics, Inc.
3 Bethesda Metro Center, Suite 1200
Bethesda, MD 20814

10. Work Unit No. (TRAIS)

11. Contract or Grant No.


12. Sponsoring Agency Name and Address

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

13. Type of Report and Period Covered

Final research report

14. Sponsoring Agency Code


15. Supplementary Notes

Government Task Manager: Neil Spiller

16. Abstract

While many of the nation's bottlenecks are addressed through costly major construction projects (i.e., "megaprojects") or costly transportation alternative solutions (e.g., high occupancy vehicle (HOV) or high occupancy toll (HOT) lanes, dynamic pricing, investments in transit alternatives, parking and commuter incentive programs, etc.) there is a significant opportunity for the greater application of operational and low-cost "fixes" at spot-specific locations.

This primer is the signature product of the Localized Bottleneck Reduction (LBR) Program, which is administered out of the Office of Operations at the Federal Highway Administration (FHWA) headquarters in Washington, D.C. The LBR program is focused on relieving recurring congestion chokepoints (as opposed to nonrecurring congestion causes) and the operational influences that cause them with lower cost, less intensive means. This is the updated, fourth edition of this primer. The first version is FHWA-HOP-07-130, the second version is FHWA-HOP-09-037, and the third version is FHWA-HOP-12-012. The first and second editions of this primer introduced, and then raised awareness about, how LBR strategies could deal with congestion, respectively. The third edition focused on providing highly specific guidance for agencies to follow in developing and advancing LBR programs. This fourth edition builds upon and updates the previous editions with recent advances in innovative research and additional case studies of implementing LBR strategies.

17. Key Words

bottleneck, localized bottleneck reduction, chokepoint, recurring congestion, low cost improvements, operational deficiencies, lane drops, weaves, merges, metering

18. Distribution Statement

No restrictions

19. Security Classif. (of this report)


20. Security Classif. (of this page)


21. No of Pages


22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed pages authorized

SI (Modern Metric) Conversion Factors

Approximate Conversions to SI Units
Symbol When You Know Multiply By To Find Symbol
in inches 25.4 millimeters mm
ft feet 0.305 meters m
yd yards 0.914 meters m
mi miles 1.61 kilometers km
in2 square inches 645.2 square millimeters mm2
ft2 square feet 0.093 square meters m2
yd2 square yard 0.836 square meters m2
ac acres 0.405 hectares ha
mi2 square miles 2.59 square kilometers km2
fl oz fluid ounces 29.57 milliliters mL
gal gallons 3.785 liters L
ft3 cubic feet 0.028 cubic meters m3
yd3 cubic yards 0.765 cubic meters m3
NOTE: volumes greater than 1000 L shall be shown in m3
oz ounces 28.35 grams g
lb pounds 0.454 kilograms kg
T short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t")
Temperature (exact degrees)
°F Fahrenheit 5 (F-32)/9 or (F-32)/1.8 Celsius °C
fc foot-candles 10.76 lux lx
fl foot-Lamberts 3.426 candela/m2 cd/m2
Force and Pressure or Stress
lbf poundforce 4.45 newtons N
lbf/in2 poundforce per square inch 6.89 kilopascals kPa
Approximate Conversions from SI Units
Symbol When You Know Multiply By To Find Symbol
mm millimeters 0.039 inches in
m meters 3.28 feet ft
m meters 1.09 yards yd
km kilometers 0.621 miles mi
mm2 square millimeters 0.0016 square inches in2
m2 square meters 10.764 square feet ft2
m2 square meters 1.195 square yards yd2
ha hectares 2.47 acres ac
km2 square kilometers 0.386 square miles mi2
mL milliliters 0.034 fluid ounces fl oz
L liters 0.264 gallons gal
m3 cubic meters 35.314 cubic feet ft3
m3 cubic meters 1.307 cubic yards yd3
g grams 0.035 ounces oz
kg kilograms 2.202 pounds lb
Mg (or "t") megagrams (or "metric ton") 1.103 short tons (2000 lb) T
Temperature (exact degrees)
°C Celsius 1.8C+32 Fahrenheit °F
lx lux 0.0929 foot-candles fc
cd/m2 candela/m2 0.2919 foot-Lamberts fl
Force and Pressure or Stress
N newtons 02.225 poundforce lbf
kPa kilopascals 0.145 poundforce per square inch lbf/in2

SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380. (Revised March 2003)

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