Diagram 581 is an important marker for an unexpected change in driving conditions due to wind. Used to warn road users that there is expected high winds across the road, the sign can be used before bridges or overpasses. High side winds can pose the most danger to large heavy goods vehicles that have truck bodies that can act as a big sails. Smaller vehicles can also be effected by strong cross winds and so the sign prepares drivers to adjust speed and prepare for an adverse change ahead.
Material: R2/RA2 reflective overlay on aluminium composite backing
18.3.1. The “side winds” sign to diagram 581 (S2‑2‑45, see Figure 18-3) is used where vehicles are suddenly exposed to risk from strong winds. Such locations may include exposed bridges or places where vehicles emerge from cuttings in areas which are particularly prone to high winds. Drivers must anticipate some adverse effects caused by side wind and in order to maintain the effectiveness of this sign, it should not be over‑used. 18.3.2. The sign may be used with “For” and a distance plate where an unusual hazard exists over a longer length, e.g. on a viaduct or high embankment. However, it should not normally be used on the open road, where drivers must expect gusts of wind.