What Are the Regulations for Flashing Beacons in the UK?

Amber Beacons: The Legal Essentials

Flashing amber beacons warn other road users that a vehicle is slower, wider or longer than normal, giving them time to adjust their speed and position.

When is a beacon legally required?
Any vehicle with a maximum speed of 25 mph — along with any trailer it's towing — must have an amber warning beacon fitted when driven on an unrestricted dual carriageway.

What type of beacon?
The beam must flash or rotate through a full 360 degrees. Unidirectional lights aren't permitted, and must never be fitted in a way that could be confused with an indicator.

Mounting height
The centre of the lamp must sit at least 1,200mm above the ground.

Visibility
The light must be visible from a reasonable distance at any point around the vehicle or trailer — front, rear and both sides.

R10 — Electromagnetic compatibility
UN ECE Regulation 10 (a United Nations standard, not a European one, which is a common misconception) has applied for nearly thirty years to any electrical equipment fitted to a vehicle that operates while the vehicle is moving. Its purpose is to prevent electromagnetic interference from one component disrupting other electrical circuits on the vehicle.

R65 — Performance and safety
Adopted across most of Europe and other UN member states, R65 sets quality and safety standards for warning lights of all types — beacons, light bars and directional units — covering both amber and emergency red/blue applications. Approval testing assesses colour, spread and intensity of light output, and confirms the flash rate falls between 2 and 4Hz.

There are two approval classes:

• Class I — a single intensity level, traditionally the norm in the amber market.
• Class II — two intensity levels, full output for daytime and reduced for night. Historically an emergency-services specification, though it's increasingly requested for amber applications too.