Why not use a solid green light instead of the flashing yellow arrow?
The solid green light is often misunderstood as a left turn indicator. This is because drivers naturally think “green means go”. Traffic making a left turn on a solid green light some times does not yield to oncoming traffic, which can result in more crashes. The flashing yellow arrow allows left turns but at the same time communicates the “caution” message to drivers. The flashing yellow left-turn arrow is especially effective at intersections with high volumes of traffic. The flashing yellow left-turn arrow will be operational when traffic volumes permit, typically during non-rush hours. Are other states using this type of signal? Several states are using this type of signal, including Nevada, Florida, Oregon, Minnesota, and others. The Federal Highway Administration (FHWA) gave interim approval for the use of the flashing yellow left-turn arrow in Missouri in spring 2006.
