Tunnels on the Italian State Roads SS 100 to SS 199, Listed by Route

• 155entries listed
• 22.4 kmtotal length

The record table

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

How this table is compiled

The material on this page is held in 10 captions rather than in running text, 82 words of it, each written against the image or row it belongs to by the compiler who put the page together. The kilometre point is recorded for each structure on the SS100-199, which is how the operator identifies it.

The captions name 24 distinct places and structures — SS125, Monte and Cucco among them — and those names are the index into the length tables where each is recorded with its own figure. Toll revenue on a fixed link is usually pledged against the debt that built it, and the toll ends when the debt does.

They are not uniform: the fullest runs to 18 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.

Only 14 of the 155 rows carry anything in the tunnels >1000 m column, so that field describes a minority of this table and the rest of the rows are recorded without it. A concrete arch takes its load into the abutments, so it needs rock at both ends and appears where valleys are steep and narrow.

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. Route numbering changes over time, so a road reference in the table reflects the designation at the time of recording.

Reading the figures

Geology decides cost and programme far more than distance does; a short bore through squeezing ground can take longer than a long one through sound rock. The cheapest kilometre of a route is the one already built, which is why upgrades follow old alignments even when a new one would be shorter.

A viaduct is measured along its deck and a bridge by its main span, and confusing the two is the commonest error in a bridge list. An immersed tube is floated into place and sunk into a dredged trench, so its length is set on land before it goes in the water.

Italian motorway inventories list tunnels and viaducts together in running order along the SS100-199. Names follow the operator's spelling, including local diacritics, not an anglicised form. A short bore in a city can cost more than a long one in a mountain, because the expensive part is what sits above it.

Cost figures are omitted throughout, since currency, inflation and scope make them close to meaningless in comparison. Administrative boundaries have been redrawn in several countries since these lists were first assembled. A hard shoulder inside a tunnel is expensive width, and its absence is why breakdowns are treated as emergencies.

Shotcrete applied at the face turned temporary support into permanent lining and changed what lengths were buildable. Water management is the maintenance problem that never ends, and drainage design decides how expensive it will be. Aerodynamic pressure waves in a long rail bore are severe enough to need relief shafts or sealed carriages.

Corrections have historically arrived by letter from engineers and administrations in more than twenty countries. Dates before 1900 are frequently approximate, and are shown as published, unreconciled. County and region codes follow the classification in use when the entry was recorded. Drill-and-blast remains normal in hard rock, and dominates the Scandinavian and Alpine entries in this record.