Tunnels and Viaducts on the D08 Motorway in Italy, by Kilometre Point

• 8entries listed
• 0.58 kmlongest bore
• 2.69 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 1.48 km of the 2.69 km on this page, which is 55 per cent of the total from 3 of 8 rows. 4 entries sit above the median and 4 at or below it, so the table is evenly weighted and not clustered at one end.

Between the longest and the tenth-longest the drop is 0.38 km, which is the part of the table that changes when a single scheme opens. Where one of these 8 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 197 m and not a rounded figure. The longest entry is 2.9 times the shortest and 1.9 times the median, which is the quickest measure of how uneven the table is.

A new scheme in Italy would have to beat 0.58 km to change the head of this table, and that is the figure worth rechecking when one opens. The eighth longest is Rivaldone at 0.2 km, which is about where this record stops being about record holders and starts being about ordinary infrastructure.

Also recorded here are Vaneggia at 0.26 km and Mambrino at 0.21 km. A tunnel list for Italy reads differently from a neighbouring country's: 0 of these 8 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.

Reading the figures

Laid end to end the entries on this page would run 2.69 km, which is a number with no engineering meaning but a useful sense of the scale of what is catalogued. The note column places the route in Lombardy, Piemont, and the administrative area is recorded because a section is identified by it.

The route table lists 8 structures with a recorded length, giving both carriageways where the two bores differ. The table on this page runs to 11 rows and records Tunnel / Viaduct, Direction Gattico, Direction Gallarate and Notes for each of them, which is the shape the original compiler chose rather than one imposed here.

The longest entry is Riviera, at 0.58 km. The 11 entries are grouped on the page under 4 headings — exit sesto calende – vergiate (6), exit castelletto ticino (2), connection a26 genova-gravellona toce (2) and exit besnate (1) — a classification the table carries as section breaks rather than as a column of its own.

The entries sum to roughly 2.69 km of bore, an average of about 0.34 km each, though that average describes no actual row. 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.

6 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. The tunnel / viaduct column names 10 distinct entries on this page, Mambrino and Melissa among them, each traceable to the operator or administration record it was taken from.