Tunnels and Viaducts on the A24 Motorway in Italy, by Kilometre Point

• 128entries listed
• 10.17 kmlongest bore
• 67.32 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 16.84 km of the 67.32 km on this page, which is 25 per cent of the total from 3 of 128 rows. 64 entries sit above the median and 64 at or below it, so the table is evenly weighted and not clustered at one end.

Where one of these 128 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. The longest entry is 254.3 times the shortest and 36.4 times the median, which is the quickest measure of how uneven the table is.

The entries sum to roughly 67.32 km of bore, an average of about 0.53 km each, though that average describes no actual row. The tunnel / viaduct column names 117 distinct entries on this page, Aniene I° and Aniene II° among them, each traceable to the operator or administration record it was taken from.

114 entries fall below a kilometre, short enough that portals and approaches usually decided their cost more than the bore itself. Read down the direction teramo column, the 114 values run from 45 to 28 809 with a midpoint at 292; the spread rather than the maximum is what says how uneven this set is.

This page records the structures catalogued along the A24 in Italy, in a tunnel almanac maintained at this address since the late 1990s. The captions name 12 distinct places and structures — Abruzzo, Settecamini and Tiburtina among them — and those names are the index into the length tables where each is recorded with its own figure.

Reading the figures

The route table lists 128 structures with a recorded length, giving both carriageways where the two bores differ. The material on this page is held in 7 captions rather than in running text, 52 words of it, each written against the image or row it belongs to by the compiler who put the page together.

Lengths for Italy are recorded in metres which is how the operators publish them and why the shortest entry here reads as 40 m and not a rounded figure. The eighth longest is Cerchiara at 1.29 km, which is about where this record stops being about record holders and starts being about ordinary infrastructure.

A new scheme in Italy would have to beat 10.17 km to change the head of this table, and that is the figure worth rechecking when one opens. The note column records 25 exits, 6 motorway connections, 2 toll barriers and 2 service areas along the route, in running order rather than by size.

San Rocco at 4.18 km and Sant’Antonio at 2.49 km follow it, and lengths are given per carriageway because the two bores of a dual route are rarely cut to the same length. Kilometre points are given where the operator publishes them, since that is how a structure is identified in the field.

Read down the direction roma column, the 122 values run from 40 to 28 790 with a midpoint at 280; the spread rather than the maximum is what says how uneven this set is. A tunnel boring machine is economic only past a certain length, below which the cost of assembling it is never recovered.