A busy intersection in Richmond is getting a traffic signal upgrade that includes a brand-new flashing yellow turn arrow signal.  Republican Representative Dick Hamm says Richmond residents asked him to work with the Indiana Department of Transportation to improve traffic signals at the congested intersection of US 40 and Salisbury Road.  INDOT spokesman Nathan Riggs says the signal now includes a new flashing yellow turn arrow that is being rolled out by transportation departments nationwide.  Riggs says in intersections with a dedicated left turn lane, the flashing yellow arrow is meant to tell drivers to turn left only after yielding to oncoming traffic and pedestrians.    INDOT says national research shows that the flashing yellow signal is more intuitive for drivers than a green arrow and helps improve safety.  The flashing yellow turn arrow will be turned on in Richmond on Thursday.