 The speed limit is also reduced to 45 miles per hour and flaggers will be on site to guide traffic through the work zone. All work should be completed by July 26th. Yavapai County encourages everyone to be alert and follow all warning signs when traveling through the Williamson Valley Road area during an upcoming fuels reduction project. County Spokesman David McAtee. Starting the week of August 12th, the Department of Forestry and Fire Management will begin work on a 263 acre fuels reduction project