NORMAN — City-contracted crews are replacing traffic signals at 57 intersections to upgrade them and add flashing yellow arrows.
Federal safety dollars are being used to fund the $300,000 project.
The flashing yellow arrows are the new federal standard for dedicated left-turn lanes.
The flashing arrow became part of new federal guidelines after studies suggested people respond to that signal better than the standard round, green light that tells drivers an unprotected left turn is legal when there is enough break in traffic to do so.
The flashing yellow arrow becomes a solid yellow arrow just before the signal turns red.
Solid green arrows will remain on signals and continue to signify protected left-hand turns, Public Works Director Shawn O’Leary said.