C17 Prohibition Sign – No Vehicles Higher than 5.3 m, Ø60 cm, Class I

C17 Prohibition Sign – No Vehicles Higher than 5.3 m, Ø60 cm, Class I

The C17 stops the driver of a vehicle taller than 5.3 m before reaching a bridge, underpass or portal it will not fit under. The value sits between two black vertical arrowheads.

When class I is used

Class I (RA1) sheeting returns 70 cd/(lx·m²) for white to the driver and has a 7-year service life, enough on roads where headlights are the only light: local, minor and private roads or quiet streets. In areas with street lighting, shop windows, advertising and dense urban traffic, however, SR 1848-2 requires prismatic class 2 or 3 sheeting.

Where it goes, under SR 1848-1:2024

It goes at both ends of bridges, underpasses, tunnels, portals and other places where the 5.50 m clearance height is not available, and at the junction leading to an alternative route; there, as with the C16, the P4 panel with the distance is added.

Like all prohibition signs, it goes right after the junction before the restricted place, so drivers can go round without turning back, and it is repeated after every junction on the section. Exemptions for residents or certain vehicle categories are shown on the P34 and P18 additional panels.

Technical data

• 60 cm diameter disc (normal format, SR 1848-2): white with a red border, with the value 5.3 m between two black vertical arrowheads;
• 1 mm galvanised steel sheet, with pressed edges, no sharp edges;
• electrostatically painted with UV-resistant paint;
• class I retroreflective sheeting (RA1), resistant to UV and weathering, with a 7-year service life;
• weight: 3 kg;
• fixings included: 2 clamps for Ø48 mm posts and 4 bolts with nuts;
• CE marked; compliant with SR EN 12899-1:2007, SR 1848-1:2024, SR 1848-2:2011 and SR 1848-3:2011.

Mounting and size

Fixings for the post are included: 2 clamps for Ø48 mm posts and 4 bolts with nuts; clamps for Ø60 mm posts are available on request. The bottom edge of the sign goes 1.50–2.50 m above the road or kerb, and the edge nearest the road 0.50–2.0 m from the road platform. The sign must be visible from at least 50 m in built-up areas and 100 m outside them.

The post is ordered separately. For a fixed installation in a concrete foundation: the galvanised Ø48 mm post, 300 cm. For temporary use, with no foundation: the Ø48 mm tripod post, 120 cm. On concrete or paving, where you cannot dig: the Ø60 mm flange post, 300 cm, bolted down; for it, ask for the Ø60 mm clamps when you order.

The 60 cm diameter is the normal format in SR 1848-2, for county and local roads, streets and private roads open to public traffic. National roads call for the large Ø80 cm format and motorways for the very large Ø100 cm one; the standard forbids using a smaller format than the road category requires.