Flashing Beacons

Flashing beacons supplement stop signs and are intended to reinforce awareness of existing stop signs.

Overhead flashing beacon for two-way stop at four-way intersection
Overhead flashing beacon for two-way stop at four-way intersection (Shutterstock).

Description

Beacons are flashing lights intended to draw a driver’s attention towards the associated traffic control.

Flashing beacons supplement stop signs and are intended to reinforce awareness of existing stop signs. Two different types of intersection beacons are typically used, including standard overhead beacons mounted over the intersection and sign-mounted beacons that may be mounted on the stop sign or stop ahead and intersection ahead signs.

Placement

  • Overhead flashing beacon for two-way stop at four-way intersection
    Overhead flashing beacon for two-way stop at four-way intersection (Shutterstock).

    Standard overhead beacons include:

    • Red flashers placed facing the stop-controlled approach and yellow flashers placed facing the unstopped approaches for two-way stop controlled intersections
    • Red flashers placed to face all approaches at all-way stop controlled intersections (Antonucci et al. 2004)
  • May be most effective at intersections with patterns of right angle crashes related to lack of driver awareness
  • Needs to be properly placed so that beacon is visible to drivers on corresponding approach

Effectiveness

Several studies have evaluated the effectiveness of beacon installation.

The following table summarizes the studies where crash reductions were found.

Crash Reduction for Installation of Intersection Flashing Beacons

StudiesLoc.# of SitesBeacon TypeCrash TypeChange in Crashes
Srinivasan et al. 2008NC and SC84standard overheadangle-11.9% (5.4)
5stop signangle-58.2% (16.3)
Pant et al. 1992OH7standard overheadfatal-56%
angle-19%
Murphy and Hummer 2007NC34standard overheadtotal-12%
injury-9%
severe injury-40%
frontal impact-9%
ran stop sign-26%
Brewer and Fitzpatrick 2004TX4standard overheadprevent -able-43%
Stackhouse and Cassidy 1996MN8standard overheadtotal-39%
4stop sign and intersection ahead signstotal-40%
Use of overhead flashing beacons in addition to stop signs at all-way stop
Use of overhead flashing beacons in addition to stop signs at all-way stop (Neal Hawkins/Institute for Transportation).

Advantages

  • Sign mounted beacons may be added to existing sign post
  • Can be implemented in a reasonable time frame

Disadvantages

  • Requires power source
  • Overhead requires support structure

More information is provided in this technical brief, Flashing Beacons, which summarizes information about flashing beacons relevant to Iowa.

References

Use of overhead flashing beacons at two-way stop for four-way intersection
Use of overhead flashing beacons at two-way stop for four-way intersection (Neal Hawkins/Institute for Transportation).

Antonucci, Nicholas D., Kelly K. Hardy, Kevin L. Slack, Ronald Pfefer, Zikhron Yaacov, and Timothy R. Neuman. Volume 12: A Guide for Reducing Collisions at Signalized Intersections.NCHRP Report 500: Guidance for Implementation of the AASHTO Strategic Highway Safety Plan. Transportation Research Board, 2004.

Stein, William J. and Timothy R. Neuman, Mitigation Strategies for Design Exceptions. Federal Highway Administration, Office of Safety. 2007.

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