The Federal Highway Administration updated the Manual on Uniform Traffic Control Devices at the end of 2009. The American Traffic Safety Services Association has been hosting free webinars about the update. The last webinar is being held next week on August 24th (click here to register).
Traffic control devices in Minnesota are governed by the Minnesota Manual on Uniform Traffic Control Devices. MnDOT is working on the update to the Minnesota version, which is located here. Stay tuned.