Flashing Lights

Flashing Lights - Do They Really Slow Traffic?

Flashing beacons (commonly called flashers or flashing lights) are frequently requested in the belief that they will reduce vehicle speeds. Unfortunately, this is not necessarily the case. The following discussion of 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.

  1. Effective Usage of Flashers
  2. Unjustified Flashers
  3. Symptoms Versus Problems

A flasher is generally installed at an intersection or in conjunction with a warning sign in advance of an area requiring greater-than-normal care by the average driver. Flashing beacons serve a useful purpose where the flashing yellow is used to alert drivers to unusual conditions that are not readily apparent, such as: obstructions in the roadway, uncommon roadway conditions, narrow bridges, or unusual conditions hidden from the motorists’ view. One of the more common locations where a flasher can be used effectively is at a signalized intersection located just beyond a vertical or a horizontal curve, where the intersection is hidden from the view of approaching travelers.

For any flasher to be effective, it must command the respect of the traveling public. In other words, immediately after seeing a flasher, the driver must consistently see an unusual condition which is being singled out for attention. Furthermore, the condition that the driver sees must be viewed as serious enough to justify his having been alerted.