Motorways in Italy — the Numbering Scheme, Routes and Structures

The record table

How this archive measures: lengths, bores, dates and ordering

How this table is compiled

Read down the length in km column, the 48 values run from 8.4 km to 759.6 km with a midpoint at 80.5 km; the spread rather than the maximum is what says how uneven this set is. Corrections have historically arrived by letter from engineers and administrations in more than twenty countries.

Only 7 of the 56 rows carry anything in the old n° column, so that field describes a minority of this table and the rest of the rows are recorded without it. Lighting at a portal is brightest in daylight, because the eye adapting from sun to bore is the hazard, not the darkness inside.

The material on this page is held in 84 captions rather than in running text, 1 101 words of it, each written against the image or row it belongs to by the compiler who put the page together. Tunnel building in Italy is shaped by geology and settlement pattern as much as by transport policy.

They are not uniform: the fullest runs to 42 words and the briefest to 6, and on a page of this kind the long ones are where the explanation lives — the caption carries what the picture cannot. A crossing whose two carriageways differ in length is recorded once per direction rather than once per crossing.

A tunnel list for Italy reads differently from a neighbouring country's, because the same journey time can be bought with one long bore in one country and a dozen short ones in another. The oldest entries in any national list are usually canal or rail, because roads were the last mode to need long bores.

Reading the figures

The table lists 48 routes with a published length in kilometres, the longest of them Milano - Napoli («Autostrada del Sole») at 759.6 km. The captions name 209 distinct places and structures — Ovest, Autostrada and Venezia among them — and those names are the index into the length tables where each is recorded with its own figure.

Squeezing ground closes on a bore faster than it can be lined, and it is the condition that has delayed more alpine schemes than any other. A freight route's ruling gradient is set by the heaviest train it must lift, and that single figure decides whether a tunnel is needed at all.

This page records the structures catalogued for Italy in a tunnel almanac maintained at this address since the late 1990s. Together the routes listed here run about 6 522 km, an average of 135.9 km each, and the median route measures 80.5 km. Italian motorway inventories list tunnels and viaducts together in running order along the autostrade.

Kilometre points are given where the operator publishes them, since that is how a structure is identified in the field. Two crossings of the same length built fifty years apart are different objects, and only the number is comparable. Spain's high-speed rail programme produced a decade of tunnelling that has no parallel in its road figures.

Shotcrete applied at the face turned temporary support into permanent lining and changed what lengths were buildable. Alpine countries dominate the rail column and coastal ones the subsea column, and neither is an accident of compilation. The number of tubes is recorded because it changes both capacity and the safety regime that applies.