Articulated Vehicles Prohibited Post Mount Sign - 622.4 R2/RA2 (Face Only)Where a length of road isnt suitable for a long vehicle with a hinged trailer, a "No articulated vehicles" sign (diagram 622. 4) should be used to prevent their access. An articulated vehicle is usually a long bus or lorry with a pivot joint to allow for sharper turning. Some areas may be too busy, tight or have adverse camber making it difficult to drive on for one of these vehicles which would lead to the use of this regulatory sign. The sign can be