Effects of Flashing Lights on Traffic
Flashing beacons (commonly called flashers or flashing lights) are frequently requested by communities in the belief that they will reduce vehicle speeds. Unfortunately, this is not necessarily the case. The page on flashing beacons is offered in the interest of broader public understanding of what flashers can do and what factors must be considered before they should be installed.
The content of this page is based on a booklet called "Flashing Lights: Do they Really Slow Traffic?", published by the Arizona Department of Transportation.
When flashers are properly located, they serve a useful function. When they are used improperly and installed in locations where they are not warranted, they soon lose much, if not all, of their effectiveness. More seriously, improper usage greatly reduces the effectiveness of other flashers installed in areas where there is a real need. Above all, it is essential to prove that there is a problem that can be solved through the installation of a flasher before actually employing one. Too often, flashers are installed when someone assumes there is, or is going to be, a problem. It is of the utmost importance that flasher installation be held to a minimum to maintain a high degree of respect for the flasher installations that are truly needed.