Shape, color and types of danger

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Triangular shape, red border: how to recognise a Belgian danger sign at a glance and identify the type of hazard it announces.

Coverage, Shape, color and types of danger

Lesson objectives

Instantly identify a danger sign by its triangular shape and red/white color Understand the general meaning of danger signs and their warning role Recognize the main families of dangers signaled (curves, roadworks, animals, obstacles)

The identity of danger signs: red triangle on white background

Danger signs form a unique and easily recognizable category : they are equilateral triangles with a red border on a white background . This shape and color allow them to be identified at a glance, even from a distance or in poor visibility. Unlike other sign categories (priority, prohibition, obligation, information), the red triangle is the universal warning signal : it prepares you for an upcoming danger and invites you to adapt your behavior.

Danger sign

Road signal with triangular shape with red border on white background. It warns of an upcoming danger and requires the driver to exercise extra caution and adapt their speed.

Red and white triangular sign on road

The six categories of road signals

In Belgium, road signs are divided into six distinct categories , each with its own shape and color. This classification allows the driver to immediately understand the type of information received:

Series Dominant shape and color Role A, Danger Triangle with red border, white background Warns of a danger: neither prohibits nor requires B, Priority Varied and intentionally distinct shapes: triangle on point (B1), octagon (B5), yellow diamond (B9, B11), square (B15, B17) Rule that takes precedence C, Prohibition Disc with red border, white background Prohibits D, Obligation Blue disc with white symbol Requires E, Stopping and parking Blue disc with red border (E1, E3); blue square (E9) Governs stopping and parking F, Information Blue rectangles or squares, sometimes white Informs, but some create a regime (F4a, F12a, F103, F111, F117) Series B is the only one whose meaning cannot be deduced from the shape: this is intentional. The octagon of the STOP sign and the yellow diamond of the priority road are recognizable even from behind, or covered in snow.

Exam tip: At the exam, you will be shown a sign and asked its category. First look at the shape (triangle, circle, rectangle, diamond) and the color (red, blue, white, yellow). These two elements are enough to identify the category, even if you don't understand the symbol in the center.

Danger signs: role and general meaning

A danger sign prohibits nothing and requires nothing : it warns . Its role is to mentally and physically prepare you for an event or situation that requires caution. When you see a red triangle, you must:

Slow down and adapt your speed to the announced danger Exercise extra caution and remain vigilant Anticipate your reaction (braking, change of direction, stopping) Respect safety distances with other vehicles

Warning

Signal that prepares the driver for an upcoming danger or particular situation. The warning neither prohibits nor requires, but asks for an adaptation of behavior and speed.

Driver slowing down in the face of a dangerous curve

The main families of dangers signaled

Danger signs cover several families of situations. Here are the main ones:

Dangerous curves : left turn, right turn, double turn Slopes and reliefs : dangerous descent, steep climb, rut or bump Narrowings : narrowing of the roadway on both sides or on one side only Reduced grip : slippery road, gravel projection Obstacles and junctions : junction with a quay, falling rocks, movable bridge Vulnerable road users : pedestrian crossing, children, cyclists, animals Roadworks : construction site in progress on the roadway Other dangers : level crossings, side wind, traffic lights, two-way traffic

Curve signs

A1a

A1a, Dangerous left turn. This sign announces a left turn considered dangerous, either by its radius or by its visibility. Before entering it, slow down. Stay well in your lane and avoid overtaking. A vehicle may appear head-on at the exit of the turn.

A1b

A1b, Dangerous right turn. This sign announces a right turn considered dangerous. Slow down well before entering it, keep your vehicle in your lane and remain vigilant at the exit, as a vehicle may appear head-on if it has cut its turn.

A1c

Double turn or succession of more than two turns, the first to the left. Several turns follow in a zigzag pattern, starting with the left. Ease off before the first turn and maintain a moderate speed until the end of the series.

A1d

Double bend or succession of more than two bends, the first to the right. The road will wind starting to the right. Slow down and remain vigilant over the entire area, even between bends. Avoid any overtaking.

Gradient and relief signs

A3

A3, Steep descent. The road will descend sharply. A percentage indicates the gradient, for example ten percent. Downshift before the descent to use engine braking and maintain a good distance from the vehicle in front of you. Avoid continuous braking, as the brakes risk overheating.

A5

A5, Steep climb. A significant hill awaits you. Downshift to maintain power and be patient, as heavy vehicles and buses may travel much more slowly. Do not attempt to overtake blindly at the top of the hill.

A13

A13, Bump or dip. A significant bump or dip crosses the road. Slow down well in advance to cross the obstacle smoothly, preserve your suspension and passenger comfort.

Road narrowing signs

A7a

Sign A7a: road narrowing on both sides. The width of the road decreases on the left and right. Slow down, center your vehicle on the lane and be attentive to oncoming vehicles, as there will be less space to pass.

A7b

A7b, Road narrowing on the left side. The left lane narrows. If you are driving there, carefully move to the right. Indicate and check your blind spot before changing lanes.

A7c

A7c, Road narrowing. The road narrows on one side. Slow down, reposition yourself in time and watch for oncoming vehicles: the passing space is reduced. Not to be confused with the lane reduction of article 12bis, which assumes a traffic lane that ends and heavily reduced traffic. Here, it is the obstacle rule of article 15.2 that applies, or signals B19 and B21 if present.

Grip and obstacle signs

A15

A15, Slippery road. The road may be particularly slippery due to rain, ice, gravel or fallen leaves. Avoid sudden braking and sharp steering movements. Increase safety distances and adapt your speed to conditions.

A17

A17, Gravel projection. The road has been recently resurfaced. Small stones may be projected by wheels. Slow down to avoid damaging your windscreen and that of vehicles following you. Maintain a good distance.

A19

A19, Beware of falling rocks. Rocks may fall from the cliff onto the road, or already be on the roadway. Slow down, watch the road carefully and be ready to avoid an obstacle. The risk is greater after heavy rain or during freeze-thaw periods.

A11

A11, Outlet onto a quay or bank. Warning: the road ends at the water's edge, whether it is a canal, port or river. Slow down significantly and be very careful. Especially at night or in poor visibility, as there is a real risk of falling into the water.

A9

A9, Movable bridge. There is no A9 motorway in this lesson: the letter A here designates the series of danger signals. The bridge opens to allow boats to pass. Slow down and be ready to stop: as soon as the red lights flash or the barriers lower, stopping is mandatory.

Vulnerable road users signs

A21

A21, Pedestrian crossing. A pedestrian crossing is ahead. Slow down and be ready to stop to let people who are crossing or waiting at the roadside pass.

A23

A23, Area specially frequented by children. This is an area where the presence of children is frequent: school, playground, daycare. Adopt increased vigilance, as a child may appear without warning. Ease off and be ready to brake.

A25

A25, Crossing for cyclists and two-wheeled moped riders, or outlet of a cycle path onto the roadway. Expect to see bicycles or mopeds crossing or entering the road. Slow down and prepare to give way if necessary.

A27

A27, Large game crossing. The letter A designates the series of danger signals, not a motorway. Deer and wild boar may cross, especially at dawn, dusk and night. An animal is rarely alone: if one crosses, wait for the others. In case of unavoidable collision, brake firmly without steering sharply.

A29

A29, Livestock crossing. Danger signal, unrelated to a motorway. Cattle, horses or sheep may occupy the roadway, often led by a shepherd. Article 10.3 is directly applicable here: any driver must slow down when approaching draft, pack or riding animals, and stop when these animals show signs of fear.

Works and other danger signs

A31

A31, Works. Construction work is underway on the roadway or nearby. Reduce your speed. Respect temporary signage and be attentive to workers and construction vehicles that may enter or leave the perimeter.

A33

A33, Traffic light signals. Traffic lights are ahead. Ease off now so you can stop without difficulty if the light turns orange or red.

A41

A41, Level crossing with barriers. Danger signal from series A, not a motorway. It announces a crossing protected by barriers: article 20.3 prohibits entering as soon as the barriers are moving or closed, as soon as the red lights flash, or as soon as the sound signal operates.

A43

A43, Level crossing without barriers. Danger signal from series A. Article 20.2 requires extra caution and only proceed after ensuring that no rail vehicle is approaching.

A37

A37, Lateral wind. Gusts from the side can destabilize your vehicle, especially if you are towing a trailer, driving a motorcycle, van or heavy vehicle. Hold the steering wheel firmly and anticipate wind gusts near bridges and open spaces.

A39

A39, Traffic allowed in both directions after a one-way section. The road you were leaving as one-way becomes two-way again. You will now meet vehicles head-on. Keep to the right, reduce your speed and adjust your trajectory.

Common exam trap: Do not confuse a danger sign (red triangle) with a prohibition sign (red circle). A red triangle warns you, a red circle forbids you. For example, sign A21 (pedestrian crossing) is a red triangle that tells you "watch out, pedestrians ahead"; sign C19 (no entry for pedestrians) is a red circle that says "pedestrians cannot pass".

How to react to a danger sign

When you spot a danger sign, your reaction must be immediate and progressive :

Recognize the red triangle from a distance Identify the type of danger (bend, roadworks, pedestrians, etc.) Anticipate the consequences (braking, change of trajectory) Adapt your speed and vigilance Maintain this caution until you have passed the danger

Article 66.2 sets the distance: danger signals are placed at an approximate distance of 150 m from the dangerous location. Two clarifications from the same article, which make excellent exam questions: signals A45 and A47 , level crossings, are an exception : they are placed at or in the immediate vicinity of the crossing; when, in particular circumstances, the signal is placed at a distance less than or greater than 150 m, this distance is indicated on an additional sign . Article 66.3 adds that the length of a dangerous section can also be indicated by an additional sign.

Key points to remember

Shape : triangle with red border on white background, series A is not confused with any other. Role : warn . A danger signal does not forbid anything and does not require anything specific; it triggers the general obligation of article 10.1 , adjust your speed according to the layout of the area, visibility and road conditions. Placement : approximately 150 m from the danger (art. 66.2), except A45 and A47 placed at the level crossing; any other distance is indicated on an additional sign, as is the length of the dangerous section (art. 66.3). Families : bends (A1a to A1d), relief (A3, A5, A13, A14), narrowing (A7a to A7c), grip (A15, A17, A19), users (A21, A23, A25), animals (A27, A29), infrastructure (A9, A11, A31, A33, A35, A37, A39, A41 to A49), and A51 , danger not defined by a special symbol, the nature of which is specified by an additional sign. Do not confuse : red triangle = warning; red-bordered disc = prohibition.

What now?

First take the quiz for this lesson to validate your learning, then practice on the exam simulator and MCQs . Next lesson: The most common signs .

BelgianLicenses

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