Temporary Traffic Signals

Temporary traffic signals control vehicle movements at roadworks where the carriageway is restricted to a single lane.
The Safety at Street Works and Road Works Code of Practice governs the use of temporary signals on UK roads.
Portable traffic signals must be set up, tested, and confirmed working before any carriageway restriction is implemented.
Signal timings must be programmed to suit the road length, traffic volume, and queue management requirements.
All-red periods must be sufficient for vehicles to clear the restricted section before opposing traffic is released.
Manual control may be needed during peak traffic periods to prevent excessive queuing and driver frustration.
Signal heads must be clearly visible to approaching traffic — obstructions, vegetation, and glare must not block the view.
Operatives setting up temporary signals must hold the relevant NRSWA competency for traffic signal installation.
Stop/go boards operated by trained personnel are an alternative to signals for short-duration, short-length works.
Regular monitoring of signal operation throughout the shift is essential — a failed signal creates dangerous head-on conflicts.

Head-on collision	A failed or incorrectly timed temporary signal releases opposing traffic simultaneously, causing head-on collisions at the restriction.
Driver compliance	Signals must be clearly visible and correctly timed — frustrated drivers who cannot see the signal or face excessive waits may ignore them.
Legal requirement	The Code of Practice requires competent installation and monitoring — non-compliant temporary signals attract prosecution and enforcement.

Do

Don't

Set up and test temporary signals before implementing any carriageway restriction.
Programme signal timings for the road length, traffic volume, and clearance time.
Ensure all-red periods allow vehicles to clear the section before opposing release.
Position signal heads where they are clearly visible to approaching traffic.
Hold valid NRSWA competency before installing temporary traffic signals.
Monitor signal operation regularly throughout the shift for faults and failures.
Use manual control during peak periods to manage queuing and prevent frustration.
Consider stop/go boards for short-duration works as an alternative to signals.
Place cones and signs to guide traffic approaching the temporary signal layout.
Brief the team on the signal setup, monitoring responsibilities, and failure procedure.

DON'T restrict the carriageway before temporary signals are set up and tested.
DON'T programme timings without calculating the correct clearance time for the road length.
DON'T set insufficient all-red time — opposing vehicles must fully clear the section.
DON'T allow vegetation, signs, or parked vehicles to obstruct signal head visibility.
DON'T install temporary signals without the required NRSWA competency qualification.
DON'T leave signals unmonitored — a fault can cause head-on traffic conflicts.
DON'T leave signals on automatic during peak traffic if queues become excessive.
DON'T use untrained persons to operate stop/go boards at traffic control points.
DON'T remove approach signing before removing the temporary signal setup.
DON'T assume signals are working correctly all day — check them at regular intervals.

See also: Highway Works Safety Awareness | Chapter 8 Signing and Guarding

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