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        Speed Management Safety
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                Methods and Practices for Setting Speed Limits: An Informational Report
fhwasa12004.pdf (7.27 MB)


(Note: This document has been converted from the original publication to 508-compliant HTML. The formatting has been adjusted for 508 compliance, but all the original text content is included, plus additional text descriptions for the images, photos and/or diagrams have been provided below.)

Cover artwork. Please see Extended Text Description below.

(*Extended Text Description:* Cover artwork for the publication "Methods and Practices for Setting Speed Limits: An Informational Report." The cover includes photos in the center of the design, depicting various speed limit signs in different environments. The first photo (on the left, center, and larger than the other photos) has a speed limit sign that reads "Speed Limit 30", next to a two-lane road running through a forest in the fall. The second photo shows a "Speed Limit 45" sign with a blue sky and a few clouds behind it. The third photo shows "Speed Limit 25" next to a road in a suburban area with green trees and grass. Under the photos is the text "FHWA Safety Program." At the bottom of the cover design are three logos, from left to right: The US Department of Transportation - Federal Highway Administration logo, the ITE - Institute of Transportation Engineers logo, and the Safe Roads for a Safer Future - Investment in roadway safety saves lives logo. In the bottom left corner is the text "FHWA-SA-12-004" and in the bottom right corer is the website link http://safety.fhwa.dot.gov.)

**Disclaimer**

The contents of this handbook reflect the views of the authors, who are responsible for the facts and the accuracy of the data published herein. The contents do not necessarily reflect the official view or policies of the Federal Highway Administration (FHWA). This handbook does not constitute a standard, specification, or regulation. It is not intended for construction, bidding, or permit purposes.

**Notice**

The United States Government does not endorse products or manufacturers. Trade or manufacturers' names appear herein solely because they are considered essential to the object of this handbook.

**Acknowledgments**

Gerald J. Forbes (F) served as the ITE Project Consultant and the overall technical editor for this report. He was responsible for the technical content and developing the case studies.

This report was based on a draft report, *Best Practices for Setting Rational Speed Limits,*prepared by Vanasse Hangen Brustlin, Inc. for the Federal Highway Administration, Office of Safety in May, 2009. Westat and Raghavan Srinivasan assisted in the development of the FHWA draft report.

ITE would like to acknowledge the following individuals who supplied information or provided comments in the development of this informational report:

Tony S. Abbo (M)
Richard F. Beaubien (F)
Leanna M. Belluz (M)
Robert Bucholc
Harry A. Campbell (F)
Tom Carmody
Christopher J. Dack (F)
Chris C. Day (M)
Andrew W. Edgar (M)
James W. Ellison (F)
John E. Fisher (F)
Kay Fitzpatrick (F)
Jenny L. Grote (F)
Abdullah J. Habibzai
Lawrence T. Hagen (F)
Wen Hu (M)
Kenton R. Jones
Arash Khoshghalb (M)
Chris King
Ryan C. Kump (M)
Greg M. Laragan (F)
Matthew P. Lawrie (M)
Mark A. Madden (M)
Sean P. Merrell (M)
Rock E. Miller (F)
Craig S. Neustaedter (F)
Michael D. Nichols (M)
Kwabena Ofosu (M)
Martin R. Parker Jr. (M)
Veronica Pelkey
Eduardo A. Petil (M)
William B. Raffensperger (M)
Lawrence E. Sefcik
Douglas A. Skowronek (M)
Harry W. Thompson (F)
Blair Turner
Elia Twigg
David C. Woodin (F)
Peter J. Yauch (F)
Erik H. Zandvliet (M)

ITE would like to acknowledge the ITE Traffic Engineering Council technical committee members who reviewed and provided comments on this report:

Gerald J. Forbes (F), Chair
Geni B. Bahar (M)
Marcus A. Brewer (M)
Wen Cheng (M)
John A. Davis (F)
Melisa D. Finley (M)
Paul Mackey (M)
Richard J. Porter (M)
Keith B. Rohling (M)
Kelly I. Schmid (M)
Rick J. Staigle (M)
James E. Tobaben (F)
John W. Van Winkle (M)

ITE would also like to acknowledge the Federal Highway Administration staff that reviewed and provided comments on this report:

Guan Xu (M), FHWA Project Manager
Craig Allred
James E. (Eric) Ferron (M)
Michael S. Griffith (M)

*Note: Letters in parentheses indicate ITE member grade: M—Member, F—Fellow.*



**Technical Report Documentation Page**

**1. Report No.**

			FHWA-SA-12-004
			**2. Government Accession No.**
			**3. Recipient's Catalog No.****4. Title and Subtitle**

			Methods and Practices for Setting Speed Limits: An Informational Report
			**5. Report Date**

			April 2012

			**6. Performing Organization Code****7. Authors**

			Gerald J. Forbes, P.Eng.
			Teresa Gardner, P.E.
			Hugh McGee, P.E., Ph.D.
			Raghavan Srinivasan, Ph.D.
			**8. Performing Organization Report** **No.****9. Performing Organization Name and Address**

			Institute of Transportation Engineers
			1627 Eye Street, NW, Suite 600
			Washington, DC 20006
			**10. Work Unit No. (TRAIS)**

			**11. Contract or Grant No.****12. Sponsoring Agency Name and Address**

			Federal Highway Administration
			Office of Safety
			1200 New Jersey Ave., SE
			Washington, DC 20590
			**13. Type of Report and Period Covered**

			April 2011-April 2012

			**14. Sponsoring Agency Code****15. Supplementary Notes**

			FHWA Project Manager: Guan Xu
			FHWA Technical Panel: Craig Allred, Eric Ferron, Michael Griffith
			ITE Project Manager: Lisa Fontana Tierney**16. Abstract**

			This informational report describes four primary practices and methodologies that are used in establishing speed limits (engineering approach, expert systems, optimization, and injury minimization). It also reviews the basic legalities of speed limits and presents several case studies for setting speed limits on a variety of roads.

			Despite the general acceptance and wide-spread use of speed limits throughout the world, there has been no consensus among practitioners concerning the methods and techniques that should be used to select the most appropriate speed limit for a particular facility. At the current time, it appears unlikely that any consensus will be achieved in the near future. This leaves practitioners without definitive guidance on this important issue, and in search of information to assist them. This report provides the information necessary for practitioners to make informed decisions in selecting a method for setting speed limits in their jurisdiction.

			This report presents the procedures that highway agencies can and do use to set speed limits. As an informational report it provides a broad overview of the different speed limit setting methods that are available for use, but it makes no specific policy recommendations or suggestions.

			Special situations, such as advisory, school zone, and work zone speeds are discussed. Speed limit enforcement and reevaluation of speed limits are discussed briefly. The design speed for the roadway will not be discussed, except as it may relate to the setting of speed limits. This is because design speed is a characteristic of the roadway that is essentially "built-in" to the road, and is not easily modified.**17. Key Words**

			Speed Limits, Traffic Control Devices, Speed Signs, Speed Measurement, Speed Study Data Collection, Speed Limit Enforcement, Statutory Speed
			**18. Distribution Statement**

			No restrictions.**19. Security Classif. (of this report)**

			Unclassified
			**20. Security Classif. (of this page)**

			Unclassified
			**21. No of Pages 22. Price**

			107 N/AForm DOT F 1700.7 (8-72) Reproduction of completed page authorized.



**SI* (Modern Metric) Conversion Factors**

**Approximate Conversions to SI Units****Symbol**
			**When You Know**
			**Multiply By**
			**To Find**
			**Symbol***Length*in
			inches
			25.4
			millimeters
			mmft
			feet
			0.305
			meters
			myd
			yards
			0.914
			meters
			mmi
			miles
			1.61
			kilometers
			km*Area*in2
			square inches
			645.2
			square millimeters
			mm2ft2
			square feet
			0.093
			square meters
			m2yd2
			square yard
			0.836
			square meters
			m2ac
			acres
			0.405
			hectares
			hami2
			square miles
			2.59
			square kilometers
			km2*Volume*fl oz
			fluid ounces
			29.57
			milliliters
			mLgal
			gallons
			3.785
			liters
			Lft3
			cubic feet
			0.028
			cubic meters
			m3yd3
			cubic yards
			0.765
			cubic meters
			m3*NOTE: volumes greater than 1000 L shall be shown in m3**Mass*oz
			ounces
			28.35
			grams
			glb
			pounds
			0.454
			kilograms
			kgT
			short tons (2000 lb)
			0.907
			megagrams (or "metric ton")
			Mg (or "t")*Temperature (exact degrees)*oF
			Fahrenheit
			5 (F-32)/9 or (F-32)/1.8
			Celsius
			oC*Illumination*fc
			foot-candles
			10.76
			lux
			lxfl
			foot-Lamberts
			3.426
			candela/m2
			cd/m2*Force and Pressure or Stress*lbf
			pound force
			4.45
			Newtons
			Nlbf/in2
			pound force per square inch
			6.89
			kilopascals
			kPa*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)



**Approximate Conversions from SI Units****Symbol**
			**When You Know**
			**Multiply By**
			**To Find**
			**Symbol***Length*mm
			millimeters
			0.039
			inches
			inm
			meters
			3.28
			feet
			ftm
			meters
			1.09
			yards
			ydkm
			kilometers
			0.621
			miles
			mi*Area*mm2
			square millimeters
			0.0016
			square inches
			in2m2
			square meters
			10.764
			square feet
			ft2m2
			square meters
			1.195
			square yards
			yd2ha
			hectares
			2.47
			acres
			ackm2
			square kilometers
			0.386
			square miles
			mi2*Volume*mL
			milliliters
			0.034
			fluid ounces
			fl ozL
			liters
			0.264
			gallons
			galm3
			cubic meters
			35.314
			cubic feet
			ft3m3
			cubic meters
			1.307
			cubic yards
			yd3*Mass*g
			grams
			0.035
			ounces
			ozkg
			kilograms
			2.202
			pounds
			lbMg (or "t")
			megagrams (or "metric ton")
			1.103
			short tons (2000 lb)
			T*Temperature (exact degrees)*oC
			Celsius
			1.8C+32
			Fahrenheit
			oF*Illumination*lx
			lux
			0.0929
			foot-candles
			fccd/m2
			candela/m2
			0.2919
			foot-Lamberts
			fl*Force and Pressure or Stress*N
			Newtons
			0.225
			pound force
			lbfkPa
			kilopascals
			0.145
			pound force 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)
      
  Background
                Purpose & Scope
                Report Organization
                The Safety of Speed
                Speed Limit Basics
                Speed Limit Sign and Placement
                Speed Study Data Collection
                Speed Limit Enforcement
                Case Studies
                Summary of Results
                References
                Appendix A: Glossary
                Appendix B: Example Traffic Control Order
                Appendix C: Illinois Policy on Setting Speed Limits
                Appendix D: Northwestern Speed Zoning Technique
                Appendix E: Speed Limits New Zealand (Road Risk Methodology)Book traversal links for Methods and Practices for Setting Speed Limits: An Informational Report
      Background › U.S. DEPARTMENT OF TRANSPORTATION

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