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Strategy G4. Relocate Signal Hardware out of Clear ZoneNCHRP Report 500 / Volume 12: A Guide for Reducing Collisions at Signalized Intersections WHERE TO USESignalized intersections where signal hardware is located within the clear zone or is a sight obstruction (particularly on high-speed approaches).
DETAILSTraffic signal hardware represents a potential roadside hazard similar to utility poles, trees, and other large fixed objects. Traffic signal supports and controller cabinets should be located as far from the edge of the pavement as possible, especially on high-speed facilities, as long as this does not adversely affect visibility of the signal indications. Consideration should be given to shielding the signal hardware if it cannot be relocated. Where there is an existing roadside barrier, the cabinet should be located behind the barrier when feasible. If practical, signal supports in medians should be located to provide more than the minimum clearance required by the agency. The signal hardware should not obstruct sight lines. Post-mounted signals in the median are discouraged due to the safety hazard they present to drivers. KEY TO SUCCESSThe new location of the signal hardware should not present a greater safety hazard than the previous location by creating a sight distance obstruction. ISSUESCare should be taken to ensure signal hardware is not relocated to a position where it obstructs sight distance or presents a safety hazard to pedestrians or bicyclists. The Americans with Disabilities Act should be consulted to ensure compliance. TIME FRAME: ShortImplementation time will be relatively short if additional right-of-way (ROW) is not needed in order to move the hardware outside the clear zone. Acquisition of ROW will increase implementation time. COSTS: ModerateCosts will be moderate if acquisition of ROW is not required to move the hardware outside the clear zone. Acquisition of ROW will increase costs. EFFECTIVENESSTRIED: Relocating the signal hardware outside the clear zone should reduce the likelihood of vehicles striking the hazard. The effectiveness of this strategy is difficult to estimate given the range of conditions and relative infrequency of such conflicts at any one location. COMPATIBILITYRelocation of signal hardware is compatible with most other strategies to improve safety at signalized intersections. SUPPLEMENTAL INFORMATIONHighway agencies should review their traffic engineering and design policies regarding the clear zone and location of signal hardware to ensure appropriate actions are being taken on routine projects. For more details on this and other countermeasures: http://safety.transportation.org For more information contact: FHWA Office of Safety Design FHWA Resource Center – Safety and Design Team 
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Program ContactEd Rice Jeffrey Shaw What’s NewRoundabout Outreach and Education Toolbox Stop-Controlled Intersection Safety: Through Route Activated Warning Systems Roundabouts: An Informational Guide, Second Edition (NCHRP Report 672) Roundabouts Peer-to-Peer Assistance How to drive a roundabout (WSDOT) Modern Roundabouts: A Safer Choice FHWA's Intersection Resources Library CD-ROM HighlightsMini-Roundabouts Technical Summary Access Management in the Vicinity of Intersections Technical Summary Intersection Safety Case Studies Intersection Safety Technologies Presentation: Intersection Safety Example Intersection Safety Implementation Plan |
