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Rapid Flashing Beacon (RFB) Details & Pedestrian Crossing Details (IS-22 & IS-23)

Note: Include the appropriate details from this page as part of the Contract Plans when an RFB system is included in a Contract.

These plans provide placement guidance and construction details for RFB system equipment.

Guidance for the installation of these types of crossings is described in the following revision to the Traffic Manual (

Chapter 3 (Delineation), Section 3.2 “Pavement Markings", item C is deleted and replaced with the following:

C. Crosswalks and Mid-block Crosswalks.
Marked crosswalks serve to guide pedestrians in the proper paths. A Traffic Engineering Study is required to establish a midblock crossing. Approval of the establishment of a marked mid-block crossing is with the Regional Administrator who delegates this approval to Region Traffic Engineer.

Traffic Engineering Study
A traffic engineering study is required to determine if the criteria is met for a marked crosswalk at a particular location, and to determine the level of marking justified. The level of detail required for a traffic engineering study will vary with the location under consideration.

The Engineering Study includes consideration of: 

  1. Speed and traffic volume data on streets being crossed. 
  2. Pedestrian volume, age, and level of mobility. 
  3. Location of pedestrian origin and destination points and crossing pattern. 
  4. Existing sidewalk network and sidewalk ramps. 
  5. Sight distance and sight obstructions. 
  6. Street characteristics including grades, curvature, pavement widths, and number of vehicle and bicycle lanes. 
  7. Location of adjacent driveways. 
  8. On-street parking. 
  9. Street lighting (Design Manual Chapter 1040.5(13) requires illumination if mid-block crossing is implemented) 
  10. Location of drainage structures. 
  11. Distance to nearest protected or marked crossing. 
  12. Traffic signal progression. 
  13. Potential for rear end accidents.

Guidance - "Supplemental Treatments for Pedestrian Crossings" (pdf, 78kb)

Construction Details
Equipment types and layouts are shown in the updated IS-22, IS-23, and IS-13B details below. The following contract specifications, RFB Contract Provisions (pdf, 54kb), should be included in any contract to ensure that the RFB system supports the required flash patterns: 

Note that for RFB systems installed on State Highways, WSDOT requires that the beacons be installed above the sign assembly. 

IS-22 RFB Details
View Plan Sheet (pdf, 108 kb)
Download WinZip File (zip, 413 kb)
(WinZip File contains the following file formats: .dgn, .dwg files

IS-23 Pedestrian Crossing Details
View Plan Sheet (pdf, 266 kb)
Download WinZip File (zip, 1.1 mb)
(WinZip File contains the following file formats: .dgn, .dwg files

For Overhead Installations, (IS-23, Sheet 12 of 12), inclusion of Plan Sheet Library (PSL) Detail IS-13B in the Contract Documents is Required.

For questions about guidance or sign placement (IS-23), please contact Rick Mowlds.
For questions about RFB equipment or installation (IS-13B or IS-22), please contact Flint Jackson.