Road sign R-304: No U-turn

What it means

«Prohibición de efectuar la maniobra de cambio de sentido de la marcha.» RD 465/2025, Annex I of the RGC (BOE-A-2025-12199), Spanish original.

The sign bans the manoeuvre of changing the direction of travel, that is, turning round to go back the way you came. It does not speak of turning left as such.

Where you meet it

You see it at a junction or stretch where turning round is not allowed.

What you must do

Do not turn round. Slowing down does not replace express authorisation: where overtaking is banned you cannot change direction either, unless a sign permits it (RGC art. 79.1). The sign that permits it expressly is S-22.

Details that count

Article 79.1 expressly bans changing direction at level crossings and in tunnels, underpasses and stretches covered by the «Tunnel» sign, whether or not visibility is good or traffic is momentarily absent. And as a general rule, where overtaking is banned you may not change direction either, unless it is expressly authorised: slowing down does not replace that authorisation. Do not mix it up with S-22, which works the other way round: it indicates the proximity of a place where a change of direction can be made at the same level. One authorises and the other bans the same manoeuvre. R-304 belongs to the residual class of «other prohibition or restriction signs» (RGC art. 145.2.d).

What it is confused with

It is confused with R-303, which bans turning left and also changing direction. It is also confused with R-305: the no-overtaking pictogram is two vehicle silhouettes, one black and one red, not a turn or U-turn arrow, which belong to the turn and U-turn ban signs.

Related signs

• R-303: No left turn
• S-22: U-turn at the same level
• R-305: No overtaking

Studied in topic 24: Changing direction.

Source: RGC arts. 79.1, 145.2.d; RGC Annex I, sign R-304 (RD 465/2025).