Two-Way Traffic Warning Sign – Diagram 521 | Permanent UK Traffic Sign

Two-Way Traffic Warning Sign – Diagram 521 | Permanent UK Traffic Sign

The Two-Way Traffic Warning Sign – Diagram 521 is an essential UK road sign used to alert drivers that they are approaching or entering a section of road where two-way traffic flows. This warning is especially important where roads transition from dual carriageways, one-way systems, or diversions into two-way configurations.

Fully compliant with TSRGD Diagram 521, BS EN 12899-1, and Chapter 4 of the Traffic Signs Manual, this triangular warning sign is available in RA2 or R3B reflective sheeting and constructed using aluminium or composite substrates for long-lasting, weather-resistant performance.

Available in all standard triangular UK sign sizes — 450mm, 600mm, 750mm, 900mm, 1200mm, and 1500mm — this sign is suitable for both temporary and permanent installations, with mounting options including channel fixings, plate-only, and self-adhesive systems.

Technical Review

This triangle warning sign features a bold upward-pointing black arrow next to a downward-pointing black arrow, both inside a red-bordered triangle. The design clearly communicates the shift to a two-way traffic environment, improving awareness and reducing the risk of head-on collisions.

Why Choose Morelock for Your Diagram 521 Sign?

Officially compliant with TSRGD and Chapter 8 standards,
Available in RA2 or R3B reflective grades for maximum visibility,
Built using robust aluminium or composite materials,
Offered in six standard triangular sizes,
Mounting systems: Channel, plate-only, or self-adhesive,
Free UK-wide delivery with fast manufacturing turnaround,

Ideal For:

• Roads transitioning from one-way to two-way traffic,
• Temporary diversion routes and contraflows,
• Motorways and dual carriageway ends,
• Rural and urban highways,
• Construction zones and roadworks,

Summary (Why You Should Buy This Product)

• Official UK sign for two-way traffic warning,
• Fully reflective and weather-resistant finish,
• Compliant with Diagram 521 and BS EN 12899-1,
• Available in 450mm–1500mm sizes,
• Manufactured in the UK with free delivery included

Product Specifications Table

Useful Road Sign Resources

Section	Link & Description
Shop Permanent Signs	Explore all Chapter 8 compliant road signs – reflective and compliant
Standard Triangle Sign Sizes	Choose from 450mm, 600mm, 750mm, 900mm, 1200mm & 1500mm – fast delivery
Permanent Installation Options	Mounting posts, fixings, and installation services across the UK
Get a Road Sign Quote	Request pricing for bulk orders or custom specifications
Government Guidance	Safety at Street Works – Official Code of Practice (PDF) The Highway Code – UK traffic signage rules and standards