Tunnels and Viaducts on the A21 Motorway in Italy, by Kilometre Point

• 34entries listed
• 12.61 kmtotal length

The record table

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

How this table is compiled

Also recorded here are Coraudia at 0.52 km and Quarto at 0.52 km. The table on this page runs to 44 rows and records Viaduct, Length (m) Direction Brescia, Length (m) Direction Torino, Notes and pk for each of them, which is the shape the original compiler chose rather than one imposed here.

The next two longest are Tanaro-Bormida at 1.28 km and Asti at 1.12 km. Read down the length (m) direction brescia column, the 34 values run from 20 m to 1 674 m with a midpoint at 202 m; the spread rather than the maximum is what says how uneven this set is.

This page records the structures catalogued along the A21 in Italy, in a tunnel almanac maintained at this address since the late 1990s. The captions name 20 distinct places and structures — Connection, Villanova and Chieri among them — and those names are the index into the length tables where each is recorded with its own figure.

The route table lists 34 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, 45 words of it, each written against the image or row it belongs to by the compiler who put the page together.

30 entries fall below a kilometre, short enough that portals and approaches usually decided their cost more than the bore itself. Piacenza at 1.46 km and Tanaro-Bormida at 1.28 km follow it, and lengths are given per carriageway because the two bores of a dual route are rarely cut to the same length.

Reading the figures

The three longest entries alone account for 4.41 km of the 12.61 km on this page, which is 35 per cent of the total from 3 of 34 rows. The shorter half of the table totals 1.7 km against 10.91 km for the longer half, from the same number of rows.

Between the longest and the tenth-longest the drop is 1.18 km, which is the part of the table that changes when a single scheme opens. Where one of these 34 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 20 m and not a rounded figure. The longest entry is 83.7 times the shortest and 8.3 times the median, which is the quickest measure of how uneven the table is.

The eighth longest is Valmanera at 0.49 km, which is about where this record stops being about record holders and starts being about ordinary infrastructure. On 1 of the structures here the two carriageways are not the same length, which is why the archive records each direction separately rather than one figure per crossing.

The longest stands 0.21 km clear of the next longest, which is the margin to watch when a new scheme is announced. Laid end to end the entries on this page would run 12.61 km, which is a number with no engineering meaning but a useful sense of the scale of what is catalogued.