The CAI Marking Network

The Club Alpino Italiano coordinates trail marking across the whole of the Italian mountain network through a system of sections, each responsible for paths within a defined territorial area. This decentralised structure means that the physical marking work is carried out by local volunteers, but the standards for mark placement, colour and format are set centrally by the CAI's national technical commission.

Every marked path in the CAI network carries a numeric code, usually displayed on a triangular sign with a red and white colour scheme. The number identifies the path within the local section's territory. Path 101 in the Brescia section is a different path from Path 101 in the Aosta section; the coding is local, not national.

CAI trail marker sign for path 902, Bologna area
CAI trail marker for path 902, Barbiano, Bologna. The red-and-white triangular sign with path number is the standard format across the national network. Photo: Sentinel447, CC0.

Paint Marks on Rock and Trees

Between signposts, paths are marked by painted bands applied directly to rock surfaces, tree trunks or purpose-made wooden posts. The standard CAI paint mark consists of two horizontal bands: the lower band is white and the upper band is red. Each band is 10 cm wide and 20 cm long, with the two bands placed immediately adjacent to one another, giving a combined mark of 10 × 20 cm in two colours.

Colour Variants by Path Type

While red and white is the standard for the general trail network, specific long-distance routes use different colour schemes to allow them to be followed independently of the local path numbering:

  • Red and white: General CAI network paths — the overwhelming majority of marked trails
  • Red and white with the letters GTA: Grande Traversata delle Alpi, the 1,000 km traverse of the western Italian Alps
  • White and green: Some regional nature park trails in northern Italy, where the park authority operates its own marking system alongside or instead of the CAI scheme
  • Yellow: Used in some municipalities in Trentino-Alto Adige for low-altitude local trails not registered in the CAI network

Signpost Standards

Signposts at junctions and trail access points follow a standardised format. The triangular or rectangular sign carries the path number in black on a white background, set within a red border. Below the path number, the sign typically lists the nearest named destination with the walking time in hours, not distance.

Walking time rather than distance is used because the relationship between distance and effort is so variable in mountain terrain. The times given on CAI signs are calculated on the basis of a pace of 300 metres of ascent per hour for uphill sections and 400–500 metres per hour for descent, applied to a fit adult without a heavy pack. Local sections are permitted to adjust these base times for particularly demanding terrain.

Mark Placement Intervals

CAI guidance specifies maximum intervals between marks depending on the difficulty rating of the path and the visibility conditions likely to be encountered:

Path Type Standard Terrain Open Ridge / Fog-Prone
T – Turistico Up to 200 m Up to 100 m
E – Escursionistico Up to 150 m Up to 80 m
EE – Escursionistico Esperti Up to 100 m Up to 50 m
EEA – Via Ferrata Fixed hardware at all key points Fixed hardware supplemented by paint

These intervals are treated as maxima, not targets. Where visibility between marks is obstructed by vegetation or rock folds, additional marks are applied regardless of the linear distance between them.

Maintenance Responsibilities

Each CAI local section is responsible for the maintenance of marks on paths within its territory. This includes repainting faded marks, replacing damaged signposts and updating destination names or times when path conditions change. The national commission carries out periodic audits and can require sections to remediate deficiencies within a defined timeframe.

In practice, the condition of marks varies considerably across the network. High-traffic paths in popular areas such as the Dolomites and the Cinque Terre are typically maintained to a high standard; remote paths in less-visited mountain ranges may have longer intervals between maintenance visits.

Digital Integration

The CAI has published an official app, Escursionismo Sicuro, which provides access to the digital version of the national trail network. Individual paths can be followed on a GPS track, and the app displays the same difficulty classifications and estimated times as the physical signposts. The underlying geographic data is maintained by the CAI in partnership with OpenStreetMap contributors who specialise in Italian mountain territory.

Path data from the CAI network is also incorporated into the OpenStreetMap database, where trails are tagged with the CAI path number, difficulty classification and surface type.

Reference Sources