Flashing Yellow Left Turn Arrow Retrofit


39 Intersections throughout Santa Rosa, CA

City or County Responsible for Project: 

City of Santa Rosa

Award Category: 

Safety or Intelligent Transportation System Projects

Narrative Description Of Your Entry: 

In 2020, the City of Santa Rosa completed the Flashing Yellow Left Turn Arrow (FYA) Retrofit project which updated 37 protected/permissive signalized intersections with FYA assemblies within City limits. A FYA signal head is a four-head signal assembly that functions very much like a dedicated left-hand turn signal, with the major difference being a flashing yellow phase prior to the solid yellow arrow. This additional phase allows vehicles to make a left hand turn after yielding to oncoming vehicles, bicyclists and pedestrians. The City of Santa Rosa strives to stay current with the latest standards and safety developments that have proven to be effective at the national level. Recently, more effective national crash reduction standards governing protected/permissive signals were adopted. The new standard replaces protected/permissive signals with FYA signals and has been adopted by multiple regulatory bodies. The new FYA assembly has shown to be much more effective in terms of response to the display, crash reduction, reduced delay and congestion, and reduced driver frustration. Funding source restrictions required City staff to design and construct the project by utilizing existing infrastructure only. No new conduits could be installed, and groundbreaking activities were prohibited. This posed significant challenges with regard to constructability due to concerns around conduit condition and capacity to accept additional conductors, given several signal systems in the project were over 30 years old. Ultimately, through coordination with City staff and the willingness of the contractor to ‘go the extra mile’, the project was able to upgrade all but two intersections originally contemplated by the project. Project construction began in February 2020 and proceeded without incident until shelter-in-place orders resulting from the COVID-19 pandemic were issued in March 2020, suspending construction activities. Project management staff and the contractor were able to restart work within two weeks of lifted restrictions; this was one of the first City of Santa Rosa Public Works projects to restart. This was achieved by maintaining consistent communication with our contractor during the stay-at-home order and because the contractor was prepared with a return to work plan meeting health order requirements. Despite the many challenges presented by COVID-19, project staff and our contractor were able to complete the project with 35 working days remaining on the contract. Upon completion of the project, a total of 67 approaches at 37 signalized intersections were updated with 134 new FYA signal heads. Based on data collected nationwide, the City is confident this project will result in a reduction of collisions for left-hand turn movement in intersections where flashing yellow arrow assemblies were installed, ultimately making the City of Santa Rosa a safer and more environmentally friendly place to work, live and play.

Submitted by: 

Grant Bailey


Associate Civil Engineer


City of Santa Rosa Transportation and Public Works


69 Stony Circle Santa Rosa, CA 95401






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