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Use of Traffic Control Devices

The standard for traffic control devices in Washington State is the 2009 Manual of Uniform Traffic Control Devices (with Revisions 1 and 2 Incorporate)  (MUTCD), as modified by Washington Administrative Code (WAC) 468-95 . The following information regarding traffic control devices is from the MUTCD and companion documents. Traffic control devices need to be designed and implemented based on laws, rules, and standards and on engineering judgment. The Traffic Services Manager provides individual assistance and recommendations on issues regarding traffic control devices.


Local and state agencies that want to test a new traffic control device that is not in the 2009 MUTCD and has not been tested or that want to use a device from the MUTCD in a way (different size, type, or location) that has not been tested can request an experimental approval from the Federal Highway Administration (FHWA).

General Information 

General Information about traffic control devices can be found in MUTCD Parts 1 , 5A , 7A , 8A , and 9A .

See WAC 468-95 for modifications for Washington State.

Traffic Signs

Traffic signs provide regulations, warnings, and guidance to the traveling public, including motor vehicles, bicycles, and pedestrians.

The following sections are from the MUTCD. See WAC 468-95 for modifications for Washington State.

General Information

Sign Types

  • Regulatory signs: MUTCD Parts 2B , 5B , 5F , 7B , 8B , and 9B
  • Warning signs: MUTCD Parts 2C , 5C , 5F , 7B , 8B , and 9B . Note: WSDOT has a ball bank indicator that local agencies may borrow to assist in determining speeds for warning signs. Contact the Local Agency Traffic Services Specialist .
  • Guide signs (Conventional Roads):
    MUTCD Parts 2D , 5D , and 9B
  • Guide signs (Freeways and Expressways):
    MUTCD Parts 2E , 5D , and 9B
  • Specific Service signs: MUTCD Part 2J
  • Tourist-Oriented Directional signs:
    MUTCD Part 2K
  • Recreational and Cultural Interest Area signs: MUTCD Part 2M
  • Emergency Management signs: MUTCD Part 2N
  • Emergency Notification signs: MUTCD Part 8B

Traffic Calming

There are temporary and permanent methods to deter cut through traffic through a neighborhood and slow motor vehicles down. These methods make conditions better for other roadway users and for neighborhood residents and businesses.

WSDOT has a radar speed gun that local agencies may borrow to conduct speed studies. Contact the Local Agency Traffic Services Specialist .

Temporary Traffic Control Devices

Temporary traffic control devices guide motor vehicles, bicycles, and pedestrians through roadway construction zones.

Additional information can be found in MUTCD Parts  5G  and  . See WAC 468-95 for modifications for Washington State.

Also learn about work zone safety and mobility .

Traffic & Ped. Signals & Beacons & ITS

General Information

Traffic signals are a vital tool used to safely and efficiently manage motor vehicle, bicycle, and pedestrian traffic.

For information, see MUTCD Parts 4 , 5F , 8C , and 9D . See WAC 468-95 for modifications for Washington State.

Adaptive signal control technology (ASCT)

Adaptive signal control technology (ASCT) is also known as adaptive traffic control systems and real-time traffic control systems. These are traffic signal systems that self-adjust to traffic conditions, demand, and capacity.

Learn more about the use of ASCT and its benefits:

Systems engineering for Intelligent Transportation Systems, including adaptive signal control

Interim Approvals for the MUTCD 

Local and state agencies that want to use a traffic control device that has been tested or is in the process of being tested and is being considered for addition to the next edition of the MUTCD can request an interim approval from FHWA. Agencies can request site specific approval or blanket, jurisdiction-wide approval.

WSDOT has received the following blanket approvals for use by all local agencies. A local agency that wants to use WSDOT's blanket approval may do so. The agency must first contact WSDOT by email to notify us that it will use the device under the blanket approval. As a condition of our approval from FHWA, the agency must provide a list of all locations where the traffic control device will be installed and must provide an updated list when locations are added or removed. For questions, please contact the Traffic Services Manager .

Traffic Laws, Rules, and Standards

Traffic laws, rules, standards, and best practices for cities and counties.


General Information

Specific Applications

The following MUTCD sections pertain to specific applications of markings. See WAC 468-95 for modifications for Washington State.

  • Pavement and Curb Markings: MUTCD Parts 3B , 5F , 7C , 8B , and 9C
  • Object Markers: MUTCD Parts 2C 9B
  • Delineators: MUTCD Part 3F
  • Colored Pavements: MUTCD Part 3G
  • Barricades and Channelizing Devices: MUTCD Part 2B , 5C , and 6F
  • Islands: MUTCD Part 3I


A modern roundabout is a circular intersection where drivers travel counterclockwise around a center island. There are no traffic signals or stop signs in a modern roundabout. Drivers yield at entry to traffic in the roundabout, then enter the intersection and exit at their desired street.

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