Tunnels and Viaducts on the A31 Motorway in Italy, by Kilometre Point

• 43entries listed
• 15.14 kmlongest bore
• 38.81 kmtotal length

The record table

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

How this table is compiled

Between the longest and the tenth-longest the drop is 14.43 km, which is the part of the table that changes when a single scheme opens. Where one of these 43 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 59 entries are grouped on the page under 14 headings — exit piacenza d'adige (18), exit velo d'astico - service areas "astico" (10), exit valle dell'astico - service areas (7), exit agugliaro (4) and service areas "castegnero" (4) — a classification the table carries as section breaks rather than as a column of its own.

The route table lists 43 structures with a recorded length, giving both carriageways where the two bores differ. The table on this page runs to 59 rows and records Tunnel / Viaduct, Direction Piovene R., Direction Rovigo and Notes for each of them, which is the shape the original compiler chose rather than one imposed here.

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 757.0 times the shortest and 42.1 times the median, which is the quickest measure of how uneven the table is.

36 entries fall below a kilometre, short enough that portals and approaches usually decided their cost more than the bore itself. Read down the direction rovigo column, the 43 values run from 20 to 27 920 with a midpoint at 370; the spread rather than the maximum is what says how uneven this set is.

Reading the figures

A new scheme in Italy would have to beat 15.14 km to change the head of this table, and that is the figure worth rechecking when one opens. The eighth longest is Sant'Agata at 0.99 km, which is about where this record stops being about record holders and starts being about ordinary infrastructure.

Also recorded here are Pedescala at 1.75 km and Cogollo at 1.56 km. A tunnel list for Italy reads differently from a neighbouring country's: 2 of these 43 structures pass three kilometres, and the same journey time is bought with one long bore in one country and a dozen short ones in another.

The three longest entries alone account for 20.94 km of the 38.81 km on this page, which is 54 per cent of the total from 3 of 43 rows. The tail of a list is where the ordinary infrastructure sits, and it is more representative of what gets built than the head is.

Read down the direction piovene r. column, the 44 values run from 20 to 28 634 with a midpoint at 365; the spread rather than the maximum is what says how uneven this set is. Local spelling and official spelling diverge often enough that a list has to choose, and this one follows the operator.

This page records the structures catalogued along the A31 in Italy, in a tunnel almanac maintained at this address since the late 1990s. The tunnel / viaduct column names 44 distinct entries on this page, Salvaterra and S.P.88 Rodigina among them, each traceable to the operator or administration record it was taken from.