Warning Line
The sign indicates a warning line
When You See This Sign
When you see a warning line you should reduce speed, keep to the right on your side of the marking and be prepared to stop or give way if necessary. Check whether the line is solid or broken - a solid line effectively means crossing is prohibited, while a broken line may allow crossing only with good visibility and after a safety assessment.
Rules & Regulations
- A warning line is a road marking (M3) that warns of specific hazards or changes in the carriageway and applies to all road users.
- Keep to your side of the warning line and adjust your speed; the line indicates that extra caution is required.
- If the warning line is solid it must not be crossed unnecessarily (e.g., for overtaking); if it is broken you may cross it only when it is safe.
- The warning line can be combined with other road signs or markings - always follow the combined instructions.
Tips for Drivers
- Reduce speed and increase attention immediately when you see a warning line - expect limited visibility or obstacles.
- Maintain a good margin from oncoming traffic and avoid overtaking near the line if visibility or space is uncertain.
- Look for supplementary signs and symbols (e.g., curves, narrow road, roadworks) that explain why the line is there.
- Use your mirrors and signal well in advance before you might need to change lanes - never cross a solid warning line to get ahead.
Common Mistakes
- Confuse the warning line with other lines and assume it always prohibits crossing - in fact, permission depends on whether the line is solid or broken.
- Assume that a warning line automatically implies a reduced speed limit - the speed limit only changes if there is a separate speed sign.
- Perform or start an overtaking maneuver just because the line is broken without first assessing visibility and oncoming traffic.
Test Yourself
Road Sign: Warning Line
How should you interpret this line?
- A It is a warning line that draws attention to an upcoming danger or change.
- B It is a guidance line that shows the direction of a walkway for visually impaired people.
- C It is a bicycle lane line that marks the cycle path.
- D It is a line for vehicles in scheduled traffic (e.g., buses).
Exam Tip
In the theory test you may be given an image question where you must decide whether crossing/overtaking is allowed - check whether the line is solid or broken and state how visibility and oncoming traffic affect the decision.
Did You Know?
The warning line (M3) is often used just before curves, narrow bridges, junctions or other locations with reduced visibility. The marking was introduced to provide a clear visual reminder that a hazard is approaching and is often used where road signs complement each other.
Frequently Asked Questions
Does the warning line apply to all vehicles?
Yes, the road marking applies to all road users, including motorcycles, cyclists and heavy vehicles. You must follow the marking regardless of vehicle type.
May I cross a warning line if no oncoming traffic is visible?
If the line is solid you must not cross it even if the road appears clear. If the line is broken you may cross it only if it is safe and overtaking rules otherwise allow it.
What does it mean if the warning line is combined with a warning sign?
The combination reinforces the message: the marking shows where the area of risk begins and the sign specifies the hazard (e.g., narrow road or sharp bend). Follow both instructions.
Does the warning line change the speed limit?
No, the warning line itself does not change the speed limit. Speed should be adjusted to the conditions and any posted speed signs.
Practice more in the app
Study Swedish road signs and driving theory in English. 314 signs with rules, tips and quizzes.