EN 50556

What is EN 50556?

When talking about traffic signal systems especially traffic signal controllers or intersection control devices EN 50556 is usually the first standard that comes to mind.
EN 50556 is a European standard specifically prepared for road traffic signal systems. It defines the technical features, safety rules, and performance requirements of systems using red, yellow, and green lights, especially for intersection controllers.
The main goal of this standard is to make sure that traffic lights work reliably in all conditions, are easy to see, and can give correct and clear messages to drivers and pedestrians at the right time.
This standard has replaced the older TS HD 638 and also includes the test procedures defined in EN 12675.

What Does It Cover?

EN 50556 covers not only traffic lights but also the entire traffic signal system, including signal controllers, signal lamps, timers, and the coordination between all components to ensure they work together properly.

Here are some of the main tests and checks included in the standard:

• Safety tests
• Vibration test
• Impact resistance test
• Protection tests (like IP tests)
• Dry heat test
• Cold test
• Wet heat test
• Electrical tests
• Electrical safety tests
• Traffic safety tests
• Electromagnetic Compatibility (EMC) test

Why Is It Important?

To receive EN 50556 certification, a traffic controller must successfully pass all of the tests mentioned in the standard. If a device passes these tests, it means it is reliable, meets international standards, and works properly.
On the other hand, devices without this certification can be a serious risk for traffic safety. Non-compliant systems should not be used because they may endanger both drivers and pedestrians.