Driving through a hilly area with a rock cutting alongside the road, you see a triangular warning sign with a red border showing rocks falling from a cliff face onto a road. What hazard is this sign warning you about?
- That rocks may fall onto the road from the high ground alongside it, or that loose rock debris may already be lying on the carriageway, so you should watch the road surface and verges closely and be ready to steer around or stop for debris
- That the road ahead is being resurfaced with loose chippings, so you should slow down to avoid stone-chip damage to your windscreen
- That the road ahead passes through an active quarry blasting zone and may be temporarily closed by a warden while blasting takes place
- That the hill ahead is prone to landslides only during heavy rain, and the sign does not apply to the hazard in dry weather
Why A? And why not the others?
Correct answer: A. That rocks may fall onto the road from the high ground alongside it, or that loose rock debris may already be lying on the carriageway, so you should watch the road surface and verges closely and be ready to steer around or stop for debris
The 'risk of falling or fallen rocks' warning triangle tells a driver that loose material from high ground beside the road may come down onto the carriageway, or that rock debris may already be lying there, so the correct reaction is heightened observation of both the verges and the road surface ahead, together with readiness to steer around debris or stop safely if the road is blocked. The option describing loose chippings from resurfacing work describes an entirely different, temporary roadworks warning about stone chips thrown up by traffic, not falling rock from a cliff face, so it misreads the symbol. The option describing an active quarry blasting zone invents a specific industrial activity and an official road closure that this general hazard sign does not indicate; the sign warns of a standing geological risk, not a scheduled blasting operation. The option limiting the hazard to heavy rain only adds a condition the sign itself does not state, since rockfalls can occur in dry weather too through frost action, erosion or simple instability, so the warning applies at all times, not just when it is raining.
Source: DfT Know Your Traffic Signs — Warning signs: Risk of falling or fallen rocks (GOV.UK)