The ST4 'Desvio de via de trânsito' sign in Portugal indicates a temporary diversion for traffic. You must adjust your driving to follow the indicated route, which may involve changes to lane layouts, priorities, or the presence of obstacles and workers. Expect altered road conditions and always be prepared to slow down and adapt until you pass the temporary section.
Master the ST4 traffic diversion sign for your Portuguese theory test revision, understanding its specific meaning and implications for safe driving. This essential road sign explanation helps you correctly interpret temporary traffic changes and make informed decisions on the road, crucial for passing your exam.
ST4 - Desvio de via de trânsito (Desvio de via de trânsito) belongs to the Portuguese temporary vertical signs category in the Regulamento de Sinalização do Trânsito. Visually, this belongs to the temporary-road-signing environment, where yellow signs, movable equipment, barriers, cones, beacons, or alignment devices guide traffic around works, closures, obstacles, and temporary hazards. The official wording is: desvio de via de trânsito. It reflects the current temporary layout and must be treated as the active instruction where works, incidents, closures, or obstacles change normal conditions. 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.
ST4 - Desvio de via de trânsito (Desvio de via de trânsito) means that the driver must understand and apply this official Portuguese instruction: desvio de via de trânsito. In practical terms, you should slow down, follow the temporary channel or instruction, and expect lanes, priorities, workers, obstacles, or carriageway limits to differ from normal.
Get clear, practical answers to the most common questions about the ST4 - ST4 - Desvio de via de trânsito (Desvio de via de trânsito) 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 ST4 sign, officially 'Desvio de via de trânsito', means there is a temporary diversion of a traffic lane. This indicates that the normal road layout is altered due to works, incidents, or obstacles, and you must follow the new, temporary route indicated by signs, cones, or barriers.
When you see the ST4 sign, you must reduce your speed, pay close attention to temporary markings and signals, and follow the diversion route provided. Be extra cautious around workers, machinery, and narrowed lanes. Expect traffic conditions to be different from the permanent layout.
Yes, you are prohibited from driving into areas that are coned off, barred, closed, or temporarily redirected. You should not assume the permanent road layout is still in effect through a work zone or incident area. Also, passing workers, obstacles, or narrow lanes too quickly or too closely is prohibited.
A common exam trap is not understanding that temporary signs and layouts override permanent ones. Learners might also fail to sufficiently reduce speed or maintain a safe distance around temporary obstacles or workers. Always treat the temporary layout as the current rule and adapt your behaviour accordingly.
The ST4 sign is part of Portugal's temporary vertical signage, regulated by the RST. These yellow signs and associated equipment are designed to guide traffic safely around temporary hazards like roadworks. They are crucial because they reflect the immediate, active road layout and must be obeyed as such.
A clear reference image of the ST4 - ST4 - Desvio de via de trânsito (Desvio de via de trânsito) road sign used in Portugal.

The ST4 - ST4 - Desvio de via de trânsito (Desvio de via de trânsito) road sign may also be known by these alternative names or terms.
The ST4 - ST4 - Desvio de via de trânsito (Desvio de via de trânsito) road sign is part of the Temporary Vertical Signs category, which groups together signs with similar rules and functions.
Reviewing similar road signs side-by-side sharpens your sign recognition skills, crucial for Portuguese theory test revision. Understanding subtle differences helps avoid confusion and ensures you comply with traffic rules for safer driving.

ST10 Circulação Alternada: Navigating Temporary Traffic Flow

ST11 Trânsito sujeito a demora: Prepare for Delays and Temporary Road Changes

ST12: Understand the Emergency Telephone Sign for Temporary Traffic Management

ST13 Accident Sign: Navigate Safely Around Incident Sites

ST14 Fim de Obras: End of Temporary Roadworks Zone Sign

ST1a: Understand the Number and Direction of Traffic Lanes

ST1b: Follow Temporary Lane Numbers and Directions

ST1c: Follow the Temporary Lane Number and Direction Instructions
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.
All Portuguese Road Signs List