Structures on the A1 var: the Variante di Valico, Bologna to Firenze

• 29entries listed
• 8.7 kmlongest bore
• 27.24 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 15.14 km of the 27.24 km on this page, which is 56 per cent of the total from 3 of 29 rows. The shorter half of the table totals 2.8 km against 24.44 km for the longer half, from the same number of rows.

Between the longest and the tenth-longest the drop is 8.14 km, which is the part of the table that changes when a single scheme opens. Where one of these 29 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.

24 entries fall below a kilometre, short enough that portals and approaches usually decided their cost more than the bore itself. Read down the direction firenze column, the 29 values run from 40 to 8 703 with a midpoint at 333; the spread rather than the maximum is what says how uneven this set is.

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 longest entry is 217.6 times the shortest and 25.0 times the median, which is the quickest measure of how uneven the table is.

A new scheme in Italy would have to beat 8.7 km to change the head of this table, and that is the figure worth rechecking when one opens. The eighth longest is Casaglia at 0.56 km, which is about where this record stops being about record holders and starts being about ordinary infrastructure.

Reading the figures

The note column places the route in Emilia, and the administrative area is recorded because a section is identified by it. Read down the direction bologna column, the 28 values run from 40 to 8 506 with a midpoint at 340; the spread rather than the maximum is what says how uneven this set is.

Val di Sambro at 3.87 km and Sparvo at 2.57 km follow it, and lengths are given per carriageway because the two bores of a dual route are rarely cut to the same length. Comparing two national lists says as much about how each country records its infrastructure as about the infrastructure itself.

The table on this page runs to 29 rows and records Tunnel / Viaduct, Direction Firenze, Direction Bologna and Notes for each of them, which is the shape the original compiler chose rather than one imposed here. The most useful sources are the least accessible: annual reports, inspection records and commissioning documents rather than press releases.

The entries sum to roughly 27.24 km of bore, an average of about 0.94 km each, though that average describes no actual row. On 19 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.

8 of the 29 entries fall within a quarter of the median length, which is how tightly this particular list clusters around its typical structure. The tunnel / viaduct column names 28 distinct entries on this page, Quercia and La Quercia among them, each traceable to the operator or administration record it was taken from.