Tunnels and Viaducts on the A33 Motorway in Italy, by Kilometre Point

• 25entries listed
• 3.53 kmlongest bore
• 20.97 kmtotal length

The record table

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

How this table is compiled

The three longest entries alone account for 9.59 km of the 20.97 km on this page, which is 46 per cent of the total from 3 of 25 rows. The shorter half of the table totals 2.1 km against 18.87 km for the longer half, from the same number of rows.

The next two longest are Verduno at 3.2 km and Gen.Franco Romano (A6) at 2.86 km. The table on this page runs to 34 rows and records Tunnel / Viaduct, Direction Cuneo, Direction Asti and Notes for each of them, which is the shape the original compiler chose rather than one imposed here.

18 entries fall below a kilometre, short enough that portals and approaches usually decided their cost more than the bore itself. Read down the direction cuneo column, the 25 values run from 35 to 9 143 with a midpoint at 595; the spread rather than the maximum is what says how uneven this set is.

Also recorded here are Stura di Demonte at 1.12 km and Mondalavia (A6) at 1.08 km. The material on this page is held in 16 captions rather than in running text, 139 words of it, each written against the image or row it belongs to by the compiler who put the page together.

This page records the structures catalogued along the A33 in Italy, in a tunnel almanac maintained at this address since the late 1990s. The captions name 24 distinct places and structures — Connection, Stura and Isola among them — and those names are the index into the length tables where each is recorded with its own figure.

Reading the figures

Between the longest and the tenth-longest the drop is 2.78 km, which is the part of the table that changes when a single scheme opens. Where one of these 25 lengths disagrees with an operator's own figure for Italy, the table keeps the published value and notes the difference instead of averaging the two.

Lengths for Italy are recorded in metres which is how the operators publish them and why the shortest entry here reads as 35 m and not a rounded figure. The longest entry is 100.8 times the shortest and 8.2 times the median, which is the quickest measure of how uneven the table is.

A new scheme in Italy would have to beat 3.53 km to change the head of this table, and that is the figure worth rechecking when one opens. The note column records 17 exits, 4 motorway connections, 2 toll barriers and 2 service areas along the route, in running order rather than by size.

The eighth longest is Tanaro 4 at 0.95 km, which is about where this record stops being about record holders and starts being about ordinary infrastructure. The ten longest average 1.72 km against 0.25 km for everything below them, and that ratio is the clearest thing this table says about the distribution.

The twelfth longest, SP 25 at 0.6 km, sits close enough to its neighbours that which of them ranks higher depends on how each was measured. 13 of them are under 500 metres, which on a route of this kind usually means a cut-and-cover section or a short spur and not a driven bore.