USA Banner
  U.S. flag
              An official website of the United States government Here's how you knowOfficial US Government Icon
              **Official websites use .gov**A **.gov** website belongs to an official government organization in the United States.
            Secure Site Icon
              **Secure .gov websites use HTTPS**
                  A **lock** ( A locked padlock ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. 
 U.S. Department of Transportation Icon United States Department of Transportation
 Search DOT
            Search
                    About FHWAFHWA Organization
                Headquarters Offices
                Field Offices
                Strategic Plan
                Business Opportunities
                Staff Directories
                Careers
                Highway History
                Contact UsProgramsAcquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                Safety
                Browse by TopicsResourcesCore Highway Topics
                Federal Aid Essentials
                Automation
                Complete Streets
                Laws and Regulations
                Policy & Guidance Center
                Section 508
                Publications and Statistics
                Professional Development
                National Highway Institute
                Resource Center
                Accessibility Resource Library
                FHWA Research LibraryNewsroomPress Releases
                Speeches & Testimony
                Photos
                Videos
                Media ContactsMenu FHWA Highway Safety Programs Home
                        Methods and Practices for Setting Speed Limits: An Informational Report


            
            In This Section
        Speed Management Safety
                USLIMITS2
                                Overview
                Create a New Project
                Revise an Existing Project
                Frequently Asked Questions
                Technical Support
                Facts & Statistics
                Engineering Speed Limits
                Traffic Calming ePrimer
                Ongoing Research
                Reference Materials
                Related Web Site Links
                
                Speed Limit Basics
Setting speed limits in the United States has always been a responsibility of State and local governments. The unrestricted freedom to exercise that authority was interrupted by the Federal Government during World War II, and more recently with the National Maximum Speed Limit of 55 mph (90 km/h). The National Maximum Speed Limit was repealed in 1995.

Every State has a basic speed statute requiring drivers to operate their vehicles at a speed that is reasonable and prudent for conditions. This basic rule is contained in the *Uniform Vehicle Code (UVC),*which provides a model set of motor vehicle laws to encourage uniformity in State traffic regulation. State statutes authorize maximum speed limits that may vary by highway type (e.g., interstate highways) or location (e.g., urban district).11

The *UVC*is a set of model traffic laws that was originally developed by the National Committee on Uniform Traffic Laws and Ordinances (NCUTLO), a now defunct, private, non-profit organization. The NCUTLO's members were mainly State governments and some related organizations. The extent to which the code is used varies by State. The *UVC*and most State motor vehicle laws include a basic speed law with wording similar to the following: No person shall drive a vehicle at a speed greater than is reasonable and prudent under the conditions and having regard for the weather, visibility, traffic, and the surface and width of the roadway.11

Section 11-803 of the *UVC*recommends States establish speed zones upon the basis of an engineering and traffic investigation. Section 11-804 outlines recommended practices on how local authorities may alter maximum limits.12

**Article VIII—Speed Restrictions**

*11-801—Basic rule*

No person shall drive a vehicle at a speed greater than is reasonable and prudent under the conditions and having regard to the actual and potential hazards then existing. Consistent with the foregoing, every person shall drive at a safe and appropriate speed when approaching and crossing an intersection or railroad grade crossing, when approaching and going around a curve, when approaching a hill crest, when traveling upon any narrow or winding roadway, and when special hazards exist with respect to pedestrians or other traffic or by reason of weather or highway conditions. (Revised, 1968)

*Uniform Vehicle Code and Model Traffic Ordinance,*2000, National Committee on Uniform Traffic Laws and Ordinances, Evanston, Illinois.

**Types of Speed Limits**

Speed limits may be classified as default/statutory regulations, or speed zoning regulations established on the basis of engineering studies. In all cases, a speed limit must be legislated (i.e., established by legislative authority).

**Statutory Speed Limits**

Statutory limits are based on the concept that uniform categories of highways can operate safely at certain maximum speeds under ideal conditions. State motor vehicle laws specify speed limits on specific categories of streets and highways. For example, a vehicle code might limit speeds to 25 mph (40 km/h) in residential areas, 30 mph (50 km/h) in business districts, and 55 mph (90 km/h) on all other roads. Generally, statutory limits apply throughout a political jurisdiction.11 Table 1 contains examples of statutory limits for three States and for the *Uniform Vehicle Code.*

**Table 1. Examples of Speed Limit Statutes**

**Jurisdiction**
			**Speed Limit Statute**Uniform Vehicle Code
			55 mph (90 km/h) in locations other than urban districts 35 mph (60 km/h) in urban districtsDelaware
			Where no special hazard exists, the following speeds shall be lawful, but any speed in excess of such limits shall be absolute evidence that the speed is not reasonable or prudent and that it is unlawful:

			All types of vehicles:

			25 mph (40 km/h) in any business district 25 mph (40 km/h) in any residential district

			20 mph (30 km/h) at all school zones where 20 mph (30 km/h) regulatory signs are in effect during specific periods

			50 mph (80 km/h) on 2-lane roadways

			55 mph (90 km/h) on 4-lane roadways and on divided roadwaysMinnesota
			10 mph (15 km/h) in alleys

			30 mph (50 km/h) on streets in urban districts

			70 mph (110 km/h) on rural interstate highways

			65 mph (105 km/h) on urban interstate highways

			65 mph (105 km/h) on expressways

			55 mph (90 km/h) on other roadsOregon
			15 mph (25 km/h) - alleys; narrow residential roadways

			20 mph (30 km/h) - business districts, school zones

			25 mph (40 km/h) - residential districts, public parks, ocean shores

			55 mph (90 km/h) - open rural highways, trucks on interstate highways

			65 mph (105 km/h) - passenger vehicles, light trucks, motor homes, and light duty commercial vehicles on interstate highways.Statutory speed limits allow for speed limits to be in effect even when it is not practical to post them.

There are two types of statutory speed limits: (a) absolute limits and (b) *prima facie*limits. The principle difference between the two types is whether someone who is charged with driving over the speed limit can defend her/his actions. An absolute speed limit is a limit above which it is unlawful to drive regardless of roadway conditions, the amount of traffic, or other influencing factors. There is no recourse to contend a charge. A *prima facie*speed limit is one above which drivers are presumed to be driving unlawfully but, if charged with a violation, they may contend that their speed was safe for conditions existing on the roadway at that time. And, therefore, that they are not guilty of a speed limit violation.

*Prima facie*limits provide greater flexibility to drivers to determine an appropriate speed for conditions and place a greater burden of proof on the enforcement community that a violation has occurred.

Approximately two-thirds of the States have absolute speed limits.11

**Speed Zones**

Where statutory limits do not fit specific road, traffic, or land uses conditions, most road authorities have the power to establish speed zones to reflect the safe maximum reasonable speed. These alternative speed limits may be higher or lower than those prescribed by the *UVC*or the statutory limits of the jurisdiction. Alternative maximum legal speed limits are established by legislating the speed zone, typically founded on the basis of an engineering study, and becoming effective when the limits are posted and properly recorded.11 Agencies process resolutions, traffic control orders, or other formal documents to properly record the legal speed limit. An example of a Traffic Control Order is shown in Appendix B.

To encourage compliance and effectively manage risk, many agencies set speed limits to reflect the "reasonable and prudent" behavior of the majority of motorists acting in an appropriate manner. This encourages drivers to obey the posted speed limit and travel at a reasonable speed. It also targets limited enforcement resources at the occasional violator who disproportionately contributes to crash risk. The concept of a rational speed limit involves a formal engineering review, during which drivers' free-flowing speeds are observed. The assumption is that by reflecting actual driver speeds, most people will consider the speed limit appropriate. Such speed limits are desirable because they encourage public compliance, reduce speed differences among drivers, and offer a defensible enforcement tool.
      
  Book traversal links for Speed Limit Basics
      ‹ The Safety of Speed
                    Up
                    Speed Limit Sign and Placement ›
                
                Book:Methods and Practices for Setting Speed Limits: An Informational Report
              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) U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

202-366-4000Subscribe to email updates
                    About
  

        
              About FHWA
                Careers
                Org Chart
                Staff Directories
                Work with UsPrograms
  

        
              Acquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                SafetyPolicies, Rights, Legal
  

        
              About DOT
                Accessibility
                Budget and Performance
                Civil Rights
                FOIA
                Information Quality
                No FEAR Act
                Office of Inspector General
                Privacy Policy
                USA.gov
                Web Policies and Notices
                Web StandardsNews & Events
  

        
              Newsroom
                Press Releases
                Speeches & Testimony
                Media Contacts
                Connect with Us