Road signs and signals
This section covers the signs and signals you must read quickly at heavy-vehicle speeds: warning, prohibitory, mandatory and information signs, plus traffic lights. The exam tests shape, colour, meaning and the action required.
Core rules
Warning signs are usually triangles with a red border; they tell you to adjust speed or look for a hazard. Prohibitory signs are circles with a red border; they forbid an action such as entry, overtaking or exceeding a weight. Mandatory signs are blue circles; they require an action such as keeping left or following a direction. Information signs are rectangles and guide you to destinations, services or lanes. Temporary roadworks signs often have a yellow background and override normal markings. At traffic lights, red means stop behind the stop line; amber means stop unless it is unsafe to do so; green means proceed only if the exit is clear. A supplementary plate under a sign gives the condition, distance or vehicle category.
Worked example
A circular sign shows a truck silhouette with “7 t” on a red-bordered circle. The shape and red border make it prohibitory, and the plate applies it to goods vehicles over 7 tonnes. If your laden vehicle is 12 tonnes, you must not enter that road, even if the route is shorter.
Traps
Confusing a warning triangle with a prohibitory circle; missing a supplementary plate that limits the sign to heavy vehicles; treating a green light as permission to block a junction; and ignoring temporary yellow signs because they look unofficial.