This article has been updated for the MUTCD 11th Edition, published December 2023 by the FHWA. The 11th Edition supersedes the 2009 MUTCD and updates requirements for speed limit signs and changeable message signs. States must adopt the 11th Edition by January 18, 2026.
MUTCD Speed Limit Sign and Changeable Message Sign Requirements
The Manual on Uniform Traffic Control Devices (MUTCD) establishes comprehensive standards for Speed Limit signs (R2-1) and changeable message signs that display speed information. The 11th Edition of the MUTCD, published in December 2023, continues and refines these requirements from prior editions.
What Changed from the 2009 Edition
Previously under the 2009 Edition, the compliance date for Speed Limit sign requirements and the color of changeable message legends was December 22, 2013. This deadline required that changeable message signs displaying approach speeds use a yellow legend on a black background (or the reverse). That compliance date has long since passed, and these are now current mandatory standards.
The 11th Edition carries forward the core speed limit sign provisions and adds updated guidance on the use of speed feedback signs, variable speed limit signs, and other intelligent transportation system (ITS) applications. The 11th Edition also includes enhanced provisions for speed management and provides additional context for engineering studies used to establish speed zones.
Section 2B.13 — Speed Limit Sign (R2-1)
The MUTCD 11th Edition specifies the following standards for speed limit signs:
Standard: Speed zones (other than statutory speed limits) shall only be established on the basis of an engineering study that has been performed in accordance with traffic engineering practices. The engineering study shall include an analysis of the current speed distribution of free-flowing vehicles.
The Speed Limit (R2-1) sign shall display the limit established by law, ordinance, regulation, or as adopted by the authorized agency based on the engineering study. The speed limits displayed shall be in multiples of 5 mph.
Speed Limit (R2-1) signs, indicating speed limits for which posting is required by law, shall be located at the points of change from one speed limit to another. At the downstream end of the section to which a speed limit applies, a Speed Limit sign showing the next speed limit shall be installed. Additional Speed Limit signs shall be installed beyond major intersections and at other locations where it is necessary to remind road users of the speed limit that is applicable.
Speed Limit signs indicating the statutory speed limits shall be installed at entrances to the State and, where appropriate, at jurisdictional boundaries in urban areas.
Establishing and Reevaluating Speed Limits
Guidance: A Reduced Speed Limit Ahead (W3-5 or W3-5a) sign should be used to inform road users of a reduced speed zone where the speed limit is being reduced by more than 10 mph, or where engineering judgment indicates the need for advance notice to comply with the posted speed limit ahead.
States and local agencies should conduct engineering studies to reevaluate non-statutory speed limits on segments of their roadways that have undergone significant changes since the last review, such as the addition or elimination of parking or driveways, changes in the number of travel lanes, changes in the configuration of bicycle lanes, changes in traffic control signal coordination, or significant changes in traffic volumes.
When a speed limit within a speed zone is posted, it should be within 5 mph of the 85th-percentile speed of free-flowing traffic.
Changeable Message Signs Displaying Speed
Option: A changeable message sign that changes the speed limit for traffic and ambient conditions may be installed provided that the appropriate speed limit is displayed at the proper times. A changeable message sign that displays to approaching drivers the speed at which they are traveling may be installed in conjunction with a Speed Limit sign.
Guidance: If a changeable message sign displaying approach speeds is installed, the legend YOUR SPEED XX MPH or such similar legend should be displayed. The color of the changeable message legend should be a yellow legend on a black background or the reverse of these colors. This requirement, originally introduced in the 2009 Edition with a December 22, 2013 compliance date, is now a fully established standard under the 11th Edition.
Additional Considerations
Option: Other factors that may be considered when establishing or reevaluating speed limits include:
- Road characteristics, shoulder condition, grade, alignment, and sight distance
- The pace
- Roadside development and environment
- Parking practices and pedestrian activity
- Reported crash experience for at least a 12-month period
No more than three speed limits should be displayed on any one Speed Limit sign or assembly. An advisory speed plaque mounted below a warning sign should be used to warn road users of an advisory speed for a roadway condition — a Speed Limit sign should not be used for this situation.
11th Edition Compliance Timeline
All previous compliance dates for speed limit signs and changeable message sign color requirements under the 2009 MUTCD have passed. Under the 11th Edition, states and local agencies must adopt the new manual by January 18, 2026. Agencies should review their speed limit sign installations and changeable message sign configurations to ensure compliance with both the carried-forward standards and any new provisions introduced in the 11th Edition.
