Approaching a road layout you haven't driven before, you see a triangular warning sign showing a standard red-amber-green traffic light symbol, with no other text. On a different road, you see the same red-amber-green symbol, but this time it has a rectangular plate beneath it stating the hours during which the signals are in operation. What is the difference between these two signs?
- The first sign means the signals ahead are temporary roadworks signals; the second means they are permanent, all-day traffic lights
- There is no real difference between the two signs; the plate beneath the second is purely decorative and provides no operationally relevant information
- The first sign means the signals ahead control pedestrian crossings only; the second means they control vehicle traffic only
- The first is a general advance warning that a fixed set of traffic signals lies ahead and will always be in operation; the second warns of signals that only operate during the stated hours, so outside those times drivers must judge the hazard for themselves rather than relying on the lights
Why D? And why not the others?
Correct answer: D. The first is a general advance warning that a fixed set of traffic signals lies ahead and will always be in operation; the second warns of signals that only operate during the stated hours, so outside those times drivers must judge the hazard for themselves rather than relying on the lights
A plain red-amber-green symbol on its own is the general 'traffic signals ahead' warning sign, advising a driver that a fixed set of signals controlling the road is coming up and will always be there. Adding a plate stating specific operating hours changes the meaning to signals that only function during those stated times, a layout commonly used at a school entrance, a narrow stretch of road, or another location where signals are not needed around the clock; outside the stated hours the lights are switched off, and the driver approaching then has to assess the hazard itself rather than wait for or rely on the signal to allocate priority. The option describing temporary roadworks signals versus permanent signals invents a distinction the plate's wording, which states hours, not a project duration, does not support. The option dismissing the plate as decorative ignores that it changes exactly when a driver can expect the signal to be operating. The option splitting the two signs into pedestrian-only and vehicle-only control fabricates a restriction neither the plain symbol nor the timed plate actually states.
Source: DfT Know Your Traffic Signs — Warning signs: Traffic signals ahead / Traffic signals that operate only at certain times (GOV.UK)