Road sign R-412: Snow chains

What it means

«Obligación de no proseguir la marcha sin cadenas para nieve u otros dispositivos antideslizantes autorizados que actúen al menos en una rueda a cada lado del mismo eje motor, o neumáticos especiales de nieve.» RD 465/2025, Annex I of the RGC (BOE-A-2025-12199), Spanish original.

To carry on you need chains, another authorised anti-skid device or snow tyres, and they must act on the drive axle, on at least one wheel each side. Fitting them on any axle is not enough: neither two wheels on the same side nor the wheels that do not drive meet the duty.

Where you meet it

You see it before the point where the obligation begins. It is a mandatory sign, the class that imposes a compulsory rule of traffic.

What you must do

Fit chains, or use snow tyres, before carrying on. The duty is about traction, not the number of wheels: chains go on the drive axle and on both sides, because their function is to transmit force to the ground symmetrically (official sign catalogue, RD 465/2025, definition of R-412; RGV art. 12.5.2).

Details that count

As a mandatory sign (RGC art. 145.2.e), R-412 does not ask you to slow down: it stops you carrying on if you do not meet the requirement. The official description speaks of «authorised» anti-skid devices: not just any gadget will do. The sister sign R-412b is called «Winter tyres» (RD 465/2025 catalogue). You can comply in three ways: with chains, with another authorised anti-skid device or with special snow tyres.

What it is confused with

The classic confusion is which axle takes the chains. The drive wheels, from «motor», receive the torque and push; they can be the front, the rear or all four depending on the vehicle's traction, so there is no fixed answer: it depends on which is your drive axle (RGC art. 92.3.d).

Related signs

• R-413: Dipped headlights
• S-5: Tunnel

Studied in topic 36: Tunnels, fog and snow.

Source: RGC arts. 92.3.d, 145.2.e; RGV art. 12.5.2; RGC Annex I, sign R-412 (RD 465/2025).