The A21 warning sign, officially known as 'Pista de aviação', indicates you are approaching an area where aircraft may be flying at low altitudes during take-off or landing. As a driver in Portugal, you must anticipate this hazard by reducing your speed before reaching the indicated area, increasing your observation distance, and being ready to brake. This sign is part of the Portuguese warning signs category, designed to alert drivers to potential dangers ahead.
This section deciphers the A21 warning sign, crucial for your Portuguese driving theory test revision. Learn to interpret its meaning and apply necessary precautions when aircraft may cross the road at low altitudes, ensuring safe driving.
A21 - Pista de aviação (Pista de aviação) belongs to the Portuguese warning signs category in the Regulamento de Sinalização do Trânsito. Visually, this belongs to the triangular red-bordered warning family used in Portugal, with the internal symbol identifying the specific hazard. The official wording is: pista de aviação: indicação da aproximação de um local em que a via pode ser sobrevoada, a baixa altitude, por aviões que tenham descolado ou que vão aterrar numa pista próxima. Its purpose is to warn early enough for the driver to adapt before the danger point. For theory preparation, connect the sign to a concrete driving decision: where to look, when to slow, whether to stop or yield, which route or lane to choose, and whether any panel changes the scope of the rule. On the road, interpret it together with markings, traffic lights, police directions, temporary works signs, and any additional panel placed with it. A strong exam answer explains both recognition and behaviour: not only what the sign is called, but what a safe and lawful driver must do next.
A21 - Pista de aviação (Pista de aviação) means that the driver must understand and apply this official Portuguese instruction: pista de aviação: indicação da aproximação de um local em que a via pode ser sobrevoada, a baixa altitude, por aviões que tenham descolado ou que vão aterrar numa pista próxima. In practical terms, you should reduce speed before the hazard, scan further ahead, increase following distance, and be ready for braking, steering, pedestrians, animals, traffic queues, or poor surface conditions.
Get clear, practical answers to the most common questions about the A21 - A21 - Pista de aviação (Pista de aviação) road sign. Learn how the sign works, what rules it represents, and how it affects real driving situations. This FAQ strengthens your understanding and supports accurate decision making for the Portuguese driving theory exam in Portugal.
The A21 'Pista de aviação' sign warns you that you are approaching a location where aircraft may be flying at low altitude, either taking off or landing on a nearby runway. It requires drivers to be extra vigilant and prepared for potential airborne activity.
When you see the A21 sign, you should immediately reduce your speed before you reach the hazard area. It's also crucial to increase your following distance and scan further ahead to anticipate any aircraft movement or its impact on traffic. Be prepared to brake or take evasive action if necessary.
A common mistake in the theory exam is not understanding the proactive behaviour required. Learners might think the sign only applies when they hear or see a plane, but the A21 demands preparation *before* reaching the hazard. Failing to slow down or increase observation in time is a typical error tested.
No, the A21 sign itself does not automatically require you to stop. It is a warning sign to prepare you for a potential hazard. You should reduce speed and increase awareness, but stopping is only necessary if an aircraft actually poses a direct risk to your safety or the safety of other road users.
Yes, it is prohibited to maintain your current speed when the hazard clearly indicates a need for earlier braking. Likewise, overtaking or changing lanes unnecessarily in the affected area can be dangerous due to reduced visibility or unpredictable aircraft noise and movement. Reacting only when you are at the hazard point is also a prohibited behaviour.
A clear reference image of the A21 - A21 - Pista de aviação (Pista de aviação) road sign used in Portugal.
The A21 - A21 - Pista de aviação (Pista de aviação) road sign may also be known by these alternative names or terms.
The A21 - A21 - Pista de aviação (Pista de aviação) road sign is part of the Warning Signs category, which groups together signs with similar rules and functions.
Comparing similar road signs aids your theory test revision by improving sign recognition and recall. Effective traffic sign comparison ensures you understand distinct meanings and reduce errors in Portugal's traffic rules. Explore more signs to solidify your knowledge.
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After reviewing the full list, explore signs by specific categories such as warning, regulatory, or informational to deepen your understanding. Practise recognizing signs in context and prepare effectively for your Portuguese driving licence theory test.
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